Sejarah elektromagnetik - Wikipedia, ensiklopedia bebas

Sejarah elektromagnetik - Wikipedia, ensiklopedia bebas

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Sejarah elektromagnetik Dari Wikipedia, ensiklopedia bebas

Sejarah elektromagnetik, yaitu pemahaman manusia dan mencatat penggunaan kekuatan elektromagnetik, tanggal kembali lebih dari dua ribu tahun; melihat kronologi elektromagnetisme. Orang dahulu akan berkenalan dengan efek atmosfer listrik, khususnya kilat [1] seperti badai di garis lintang paling selatan adalah umum, dan mereka juga tahu dari St Elmo's api. Namun mereka memiliki sedikit pemahaman tentang listrik, dan tidak mampu menjelaskan secara ilmiah fenomena tersebut. [2]

Isi 1 2 3 4

Daya Listrik dan magnet kuno dan sejarah klasik Abad Pertengahan dan Renaissance abad ke-18 Meningkatkan 4,1 mesin listrik 4,2 Listrik dan non-listrik 4,3 vitreous dan resinous 4,4 Leyden jar 4,5 Akhir 1700-an

5 abad ke-19 5,1 Awal 1800-an 5,2 Faraday dan Henry 1800-an Tengah 5,3 5,4 Maxwell, Hertz, dan Tesla Akhir dari 5,5 abad Revolusi Industri Kedua 5,6 6 abad ke-20 6,1 Lorentz, dan Poincaré 6,2 Annus mirabilis Einstein 7 abad ke-21 Wireless 7,1 listrik 8 Lihat pula 9 Lihat 10 Bibliografi

Listrik dan magnet Listrik diperlakukan secara bersama-sama dengan magnetisme, karena keduanya biasanya akan muncul bersama-sama; di mana pun yang pertama bergerak, yang terakhir ini juga hadir. [3] Fenomena magnet diamati awal dalam sejarah magnetisme, tetapi tidak sepenuhnya menjelaskan sampai gagasan dari induksi magnetik dikembangkan. [4] Fenomena listrik diamati dalam sejarah awal listrik, tapi tidak sepenuhnya menjelaskan sampai ide muatan listrik sepenuhnya dikembangkan.

sejarah kuno dan klasik Pengetahuan tentang listrik statis tanggal kembali ke peradaban paling awal, tapi selama ribuan tahun itu tetap hanya merupakan fenomena menarik dan menakjubkan, tanpa teori untuk menjelaskan perilaku dan seringkali bingung dengan magnetisme. Orang dahulu itu berkenalan dengan sifat-sifat aneh lainnya yang dimiliki oleh dua mineral, kuning (ἤλεκτρον) dan bijih besi magnetik. Yang pertama, ketika digosok, menarik tubuh cahaya: yang terakhir ini memiliki kekuatan menarik besi. [5] Berdasarkan temuannya dari Olmec bijih besi artefak di Amerika Tengah, astronom Amerika John Carlson telah menyarankan bahwa "Olmec mungkin telah menemukan dan menggunakan kompas magnet geomagnetic lebih awal dari 1000 SM". Jika benar, ini "mendahului penemuan Cina lodestone geomagnetic kompas oleh lebih dari satu millenium". [6] [7] Carlson Olmecs berspekulasi bahwa mungkin telah menggunakan artifak serupa sebagai perangkat arah untuk astrologi atau geomantis tujuan, atau untuk mengorientasikan kuil-kuil mereka, rumah-rumah yang hidup atau interments orang mati. Paling awal sastra cina referensi untuk magnet terletak pada abad ke-4 SM sebuah buku berjudul Kitab Lembah Iblis Master ( ): "The lodestone membuat besi datang atau menarik itu." [8] Penemuan amber dan zat serupa lainnya [9] pada zaman dahulu menunjukkan persepsi yang mungkin dengan manusia pra-sejarah. [10] [11] yang kebetulan bergesekan dengan kulit yang ia berpakaian sendiri mungkin disebabkan oleh daya tarik resin, dengan demikian listrik, cahaya cukup ditandai bulu di gelar untuk menangkap perhatiannya. [12] Antara semacam itu hanya pengamatan terhadap fakta, bagaimanapun, dan pembuatan pengurangan apapun dari itu, periode besar mungkin telah berlalu, tetapi ada datang suatu waktu pada akhirnya, ketika ambar dipandang sebagai benda mati yang aneh zat yang dapat mempengaruhi atau bahkan menarik ke dirinya sendiri hal-hal lain dan ini dengan kapasitas jelas sendiri, dan tidak melalui obligasi atau sambungan mekanis yang terbentang dari pada mereka; ketika diakui, dalam singkat, bahwa alam tak bernyawa mengadakan hal yang menunjukkan atribut kehidupan. [12] Jauh sebelum pengetahuan tentang elektromagnetisme ada, orang-orang secara tidak langsung menyadari efek listrik. Petir, tentu saja, dan manifestasi tertentu lainnya listrik, yang dikenal dengan para filsuf kuno kali, tetapi kepada mereka tidak berpikir lebih jauh dari itu manifestasi ini mempunyai asal mula yang sama. [13] Mesir Kuno sadar guncangan saat berinteraksi dengan ikan listrik (seperti Malapterurus electricus) atau binatang lain (seperti belut listrik). [14] The guncangan dari binatang itu jelas bagi pengamat sejak pra-sejarah dengan berbagai bangsa yang datang ke dalam kontak dengan mereka. Teks-teks dari 2750 SM oleh kuno Mesir, ikan ini disebut sebagai "Guntur dari Sungai Nil", dan melihat mereka sebagai "pelindung" dari semua ikan lainnya. [5] Mungkin yang paling awal dan pendekatan terdekat penemuan identitas petir, dan listrik dari sumber lain, adalah dapat diberikan ke orang-orang Arab, yang sebelum abad ke-15 memiliki kata Arab untuk petir (Raad) diterapkan pada sinar Electric. [13] Menurut Thales Miletus, menulis sekitar 600 SM, mencatat bahwa bentuk listrik yang diamati oleh orang Yunani Kuno yang tertentu akan menyebabkan daya tarik dengan mengusap bulu pada berbagai zat, seperti ambar. [15] Thales wrote on efek sekarang dikenal sebagai listrik statis. Orang Yunani mencatat bahwa tombol ambar dapat menarik benda-benda ringan seperti rambut dan bahwa jika mereka mengusap ambar cukup lama mereka bahkan bisa mendapatkan percikan untuk melompat. Selama kali ini dalam alkimia dan filsafat alam, keberadaan medium dari ether, ruang-zat atau mengisi lapangan, pikir ada.

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Fenomena elektrostatis kembali dilaporkan ribuan tahun kemudian oleh Romawi dan Arab naturalis dan dokter. [16] Beberapa penulis kuno, seperti Pliny the Elder dan Scribonius Largus, dibuktikan dengan efek mati rasa kejutan listrik yang disampaikan oleh lele dan torpedo sinar. Pliny dalam bukunya menulis: "Tuscans kuno mereka terus belajar bahwa ada sembilan dewa yang mengirimkan petir dan sebagainya sebelas orang macam." Hal ini secara umum gagasan pagan awal petir. [13] The kuno menyelenggarakan beberapa konsep yang guncangan sepanjang perjalanan bisa melakukan objek. [17] Pasien yang menderita penyakit seperti asam urat atau sakit kepala diarahkan untuk menyentuh ikan listrik dengan harapan bahwa sentakan kuat mungkin menyembuhkan mereka. [18] Sejumlah benda yang ditemukan di Irak pada tahun 1938 tanggal untuk abad-abad awal Masehi (Sassania Mesopotamia), yang disebut Baghdad Battery, menyerupai sel galvanik dan diyakini oleh beberapa telah digunakan untuk elektroplating. [19] Klaim yang kontroversial karena bukti pendukung dan teori-teori untuk penggunaan artefak, [20] [21] bukti fisik pada benda-benda yang kondusif bagi fungsi listrik, [22] dan jika mereka listrik di alam. Sebagai hasil sifat benda-benda ini didasarkan pada spekulasi, dan fungsi artefak tersebut masih diragukan. [23]

Abad Pertengahan dan Renaissance Upaya untuk menjelaskan daya tarik magnetis sebagai kerja suatu jiwa di dalam batu menyebabkan serangan pertama akal manusia atas dasar takhayul dan filsafat. Setelah selang berabad-abad, sebuah kapasitas baru lodestone menjadi terungkap dalam polaritas, atau tampilan efek berlawanan di ujung-ujung, lalu datang pemanfaatan pertama sejauh pengetahuan yang diperoleh, di kompas pelaut, yang mengarah ke penemuan Dunia Baru, dan melemparkan luas semua portal Lama untuk perdagangan dan peradaban. [12] Pada abad ke-11, di Cina ilmuwan Shen Kuo (1031-1095) adalah orang pertama yang menulis tentang jarum magnetik kompas dan bahwa meningkatkan ketepatan navigasi dengan mempekerjakan astronomi konsep utara sejati (Dream Pool Essay, AD 1088) , dan pada abad ke-12 orang Cina diketahui menggunakan magnet kompas untuk navigasi. Pada tahun 1187, Alexander Neckham merupakan yang pertama di Eropa untuk menggambarkan kompas dan penggunaannya untuk navigasi. Magnetisme adalah salah satu dari sedikit ilmu-ilmu yang berkembang pada abad pertengahan Eropa, karena pada abad ketiga belas Petrus Peregrinus, penduduk asli Maricourt di Picardy, membuat penemuan pentingnya. [24] Para sarjana Perancis abad ke-13 melakukan percobaan pada magnet dan menulis masih ada risalah pertama yang menggambarkan sifat-sifat magnet dan jarum kompas berputar. [5] Uskup Agung Eustathius dari Tesalonika, Yunani sarjana dan penulis dari abad ke-12, mencatat bahwa Woliver, raja dari Goth, mampu menarik bunga api dari tubuhnya. Penulis yang sama menyatakan bahwa filsuf tertentu dapat sewaktu berpakaian untuk menarik bunga api dari pakaian, tampaknya hasil yang serupa dengan yang diperoleh oleh Symmer dalam percobaan stoking sutra, rekening yang hati-hati yang dapat ditemukan dalam "Philosophical Transactions, '1759 . [13] Dokter Italia Girolamo Cardano menulis tentang listrik dalam De Subtilitate (1550) membedakan, mungkin untuk pertama kalinya, antara listrik dan gaya magnet. Menjelang bagian akhir abad ke-16 seorang dokter dari Ratu Elizabeth waktu, Dr William Gilbert, dalam De Magnete, memperluas karya Cardano dan menciptakan Latin Baru kata electricus dari ἤλεκτρον (elektron), kata Yunani untuk "ambar". Penggunaan pertama dari kata listrik dinisbahkan kepada Sir Thomas Browne dalam kerja 1646, Pseudodoxia Epidemica. Gilbert melakukan sejumlah eksperimen listrik hati-hati, dalam perjalanan yang ia temukan bahwa banyak zat selain ambar, seperti belerang, lilin, kaca, dll, [25] yang mampu mewujudkan sifat listrik. Gilbert juga menemukan bahwa tubuh dipanaskan kehilangan listrik dan mencegah kelembaban elektrifikasi dari semua benda, karena sekarang terkenal fakta bahwa gangguan kelembaban isolasi tubuh tersebut. Dia juga memperhatikan bahwa zat listrik tertarik semua zat-zat lain tanpa pandang bulu, sedangkan hanya magnet menarik besi. Banyak penemuan alam ini diterima bagi Gilbert gelar pendiri ilmu listrik. [13] Perintis lain adalah Robert Boyle, yang pada tahun 1675 menyatakan bahwa daya tarik dan tolakan listrik dapat bertindak di ruang hampa. Salah satu penemuan penting adalah bahwa badan listrik dalam ruang hampa akan menarik zat cahaya, ini menunjukkan bahwa efek listrik tidak tergantung kepada udara sebagai media. Ia juga menambahkan resin ke daftar kemudian dikenal listrik. [13] [26] Hal ini diikuti pada tahun 1660 oleh Otto von Guericke, yang menemukan awal elektrostatik generator. Pada akhir abad ke-17, para peneliti telah mengembangkan cara praktis untuk pembangkit listrik oleh gesekan dengan generator elektrostatik, tapi pengembangan mesin elektrostatik tidak dimulai dengan sungguh-sungguh hingga abad ke-18, ketika mereka menjadi alat yang fundamental dalam studi tentang baru ilmu listrik.

abad ke-18 Meningkatkan mesin listrik Mesin listrik kemudian diperbaiki oleh Francis Hauksbee atau Hawksbee, Litzendorf, dan oleh Prof Georg Matthias Bose, sekitar 1750. Litzendorf diganti bola kaca untuk bola belerang Guericke. Boze adalah yang pertama untuk menggunakan "perdana kondektur" di mesin seperti itu, ini terdiri dari sebuah batang besi yang diadakan di tangan seseorang yang tubuhnya terisolasi dengan berdiri di atas kue dari resin. Dr Ingenhousz, pada tahun 1746, menemukan mesin-mesin listrik yang terbuat dari kaca. [27] Percobaan dengan mesin listrik sebagian besar dibantu oleh penemuan properti sebuah piring kaca, ketika dilapisi di kedua sisinya dengan kertas timah, mengumpulkan muatan listrik ketika terhubung dengan sumber tenaga listrik. Mesin listrik segera lebih ditingkatkan oleh Andrew Gordon, seorang Skotlandia, Profesor di Erfurt, yang menggantikan kaca tempat silinder di sebuah bola kaca, dan oleh Giessing Leipzig yang menambahkan sebuah "karet" yang terdiri dari bantal dari bahan wol. Kolektor, yang terdiri dari serangkaian logam poin, ditambahkan ke mesin oleh Benjamin Wilson tentang 1746, dan pada 1762, John Kanton dari Inggris (juga penemu pertama-bola empulur electroscope) meningkatkan efisiensi mesin-mesin listrik oleh percikan campuran dari timah di atas permukaan karet. [13]

Listrik dan non-listrik Pada 1729, Stephen Gray melakukan serangkaian percobaan yang menunjukkan perbedaan antara konduktor dan non-konduktor (isolator), menunjukkan antara lain bahwa kawat logam dan bahkan benang dilakukan pak listrik, sedangkan sutra tidak. Dalam salah satu eksperimennya ia mengirim arus listrik melalui 800 meter dari benang serat rami yang ditangguhkan pada interval oleh lingkaran benang sutera. Ketika ia mencoba melakukan eksperimen yang sama untuk mengganti sutra halus kawat kuningan berputar, ia menemukan bahwa arus listrik tidak lagi dilakukan di seluruh tali rami, tetapi sepertinya menghilang ke kawat kuningan. Dari percobaan ini ia zat diklasifikasikan ke dalam dua kategori: "listrik" seperti kaca, resin dan sutra dan "non-listrik" seperti logam dan air. "Electric" tuduhan dilakukan sementara "non-listrik" yang diselenggarakan tuduhan. [13] [28]

vitreous dan resinous Tergelitik oleh Gray hasil, pada 1732, CF du Fay mulai melakukan beberapa eksperimen. Dalam percobaan pertama, Du Fay menyimpulkan bahwa semua benda kecuali logam, hewan, dan cairan dapat listrik dengan mengusap dan logam, hewan dan cairan dapat listrik melalui mesin listrik, sehingga mendiskreditkan Gray's "listrik" dan "non - listrik "klasifikasi zat. Tahun 1737 Du Fay dan mandiri Hawksbee menemukan apa yang mereka yakini sebagai dua jenis gesekan listrik; satu yang dihasilkan dari menggosok kaca, yang lain dari menggosok damar. Dari sini, Du Fay berteori bahwa listrik terdiri dari dua cairan listrik, "kaca" dan "resinous", yang dipisahkan oleh gesekan dan menetralisir satu sama lain ketika gabungan. [29] Ini dua teori fluida yang kemudian menimbulkan konsep positif dan negatif muatan listrik yang dirancang oleh Benjamin Franklin. [13]

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Leyden jar The Leiden jar, sejenis kapasitor untuk energi listrik dalam jumlah besar, diciptakan di Universitas Leiden oleh Pieter van Musschenbroek di 1745. William Watson, saat melakukan percobaan dengan botol Leyden, yang ditemukan pada tahun 1747 bahwa pelepasan listrik statis ekuivalen dengan arus listrik. Kapasitif properti, sekarang dan selama bertahun-tahun di availed dari kondensor listrik, pertama kali diamati oleh Von Kleist Leiden di 1754. [30] Von Kleist terjadi untuk memegang, dekat mesin listrik, botol kecil, di leher yang ada kuku besi. Menyentuh kuku besi secara tidak sengaja dengan tangannya yang lain dia menerima sengatan listrik yang parah. Dalam banyak cara yang sama Prof Pieter van Musschenbroeck dibantu oleh Cunaens menerima kejutan yang lebih parah dari yang agak mirip botol kaca. Sir William Watson dari Inggris sangat meningkat perangkat ini, dengan menutup botol, atau jar, luar dan dalam dengan kertas timah. Bagian aparatus listrik akan dengan mudah diakui sebagai Leiden terkenal jar, jadi dipanggil oleh Nollet Abbas Paris, setelah tempat penemuannya. [13] Pada 1741, Ellicott "diusulkan untuk mengukur kekuatan elektrifikasi oleh kekuatan untuk menaikkan berat di salah satu skala keseimbangan, sementara yang lain diadakan di atas tubuh listrik dan menarik untuk itu oleh kekuasaan menarik". Sir William Watson yang telah disebutkan melakukan berbagai eksperimen, sekitar 1749, untuk memastikan kecepatan listrik dalam suatu kawat, yang percobaan, meskipun mungkin tidak begitu dimaksudkan, juga menunjukkan kemungkinan penularan sinyal untuk jarak dengan tenaga listrik. Dalam percobaan ini kawat terisolasi 12.276 kaki panjang dipekerjakan dan transmisi sinyal dari satu ujung kabel yang lain ke pengamat muncul untuk seketika. Monnicr di Prancis sebelumnya yang telah dibuat mirip percobaan, mengirim guncangan melalui besi kawat panjang 1.319 meter. [13] Tentang 1750 berbagai tes yang dilakukan oleh berbagai percobaan untuk memastikan efek fisiologis dan therapeutical listrik. Mainbray (atau Mowbray) di Edinburgh meneliti efek listrik pada tanaman dan menyimpulkan bahwa pertumbuhan dua pohon melati itu dipercepat oleh elektrifikasi. Myrtles ini adalah listrik "selama seluruh bulan Oktober, 1746, dan mereka meletakkan cabang-cabang dan sebagainya bunga lebih cepat dari semak lainnya dari jenis yang sama tidak listrik.". [31] The Abbé Menon mencoba efek dari sebuah aplikasi tetap listrik pada laki-laki dan burung dan menemukan bahwa subjek percobaan pada kehilangan berat badan, dengan demikian tampaknya menunjukkan bahwa listrik mempercepat ekskresi. Kemanjuran kejutan listrik dalam kasus-kasus kelumpuhan diuji di rumah sakit daerah di Shrewsbury, Inggris, dengan agak miskin sukses. [32] Dalam satu kasus yang dilaporkan lengan yang lumpuh itu agak membaik, tetapi ketakutan dari guncangan menjadi begitu besar sehingga pasien lebih suka mengorbankan kemungkinan daripada mengobati menjalani perawatan lebih lanjut. Dalam kasus lain kelumpuhan parsial pengobatan listrik itu diikuti oleh sementara lumpuh total. Aplikasi kedua perawatan ini kembali diikuti oleh kelumpuhan total, lalu sesudah itu lebih jauh penggunaan listrik dalam kasus ini dihentikan. Untuk lebih account dari awal penggunaan listrik sebagai agen perbaikan pembaca dapat berkonsultasi De la Rive's 'Listrik.' [33]

Akhir 1700-an Pada 1752, Benjamin Franklin sering bingung sebagai kunci termasyhur di belakang listrik. William Watson dan Benjamin Franklin berbagi penemuan potensi listrik. Benjamin Franklin dipromosikan penyelidikannya listrik dan teori-teori melalui terkenal, meskipun sangat berbahaya, percobaan yang menerbangkan layang-layang melalui badai-terancam langit. Kunci yang terikat pada tali layang-layang memicu dan dikenakan Leyden jar, sehingga membentuk hubungan antara petir dan listrik. [34] Setelah percobaan tersebut ia menemukan sebuah penangkal petir. Hal ini baik Franklin (lebih sering) atau Ebenezer Kinnersley dari Philadelphia (lebih jarang) yang dianggap sebagai pendiri konvensi positif dan listrik negatif. Teori mengenai sifat listrik cukup jelas pada periode ini, dan yang menonjol lebih atau kurang bertentangan. Franklin menganggap bahwa listrik adalah fluida yg tdk terbayangkan akibatnya meresapi segala sesuatu, dan yang, dalam kondisi normal, adalah didistribusikan merata di semua zat. Dia menganggap bahwa manifestasi listrik yang diperoleh dengan menggosok kaca disebabkan produksi kelebihan cairan listrik dalam substansi dan bahwa manifestasi diproduksi dengan menggosokkan lilin itu disebabkan defisit dari fluida. Teori ini ditentang oleh "dua-cairan" teori karena Robert Symmer, 1759. Dengan teori Symmer's resinous electricities vitrous dan dianggap Benjamin Franklin sebagai cairan yg tdk terbayangkan akibatnya, masing-masing terdiri dari cairan menjadi saling pengusir partikel partikel sementara yang berlawanan saling menarik busur electricities. Ketika kedua cairan bersatu dengan alasan ketertarikan mereka satu sama lain, efeknya pada objek eksternal dinetralkan. Tindakan menggosok tubuh terurai cairan salah satu yang tetap dalam kelebihan pada tubuh dan memanifestasikan dirinya sebagai resinous vitrous atau listrik. [13] Hingga saat bersejarah Franklin layang-layang percobaan [35] identitas listrik yang dikembangkan oleh menggosok dan mesin-mesin listrik (gesekan listrik), dengan petir umumnya tidak ditetapkan. Dr Wall, Abbas Nollet, Hawkesbee, Gray dan Winckler memang menyarankan kemiripan antara fenomena "listrik" dan "petir," kata Gray telah mengisyaratkan bahwa mereka hanya berbeda dalam derajat. Ini tidak diragukan lagi Franklin Namun, yang pertama kali mengusulkan tes untuk menentukan kesamaan dari fenomena. Dalam sebuah surat kepada Petrus Comlinson, London, 19 Oktober 1752. Franklin, merujuk kepada eksperimen layang-layang, menulis, "Pada tombol ini botol (Leiden jar) dapat dikenakan biaya, dan dari api listrik sehingga roh-roh yang diperoleh dapat dinyalakan, dan semua percobaan listrik lainnya dibentuk yang biasanya dilakukan oleh bantuan menggosok bola kaca atau tabung, dan dengan demikian kesamaan masalah listrik dengan petir benar-benar ditunjukkan. "[36] Dalibard, di Marley, dekat Paris, pada 10 Mei 1742, dengan menggunakan batang besi vertikal 40 kaki panjang, hasil yang diperoleh sesuai dengan yang dicatat oleh Franklin dan agak sebelum tanggal Franklin percobaan. Franklin demonstrasi penting dari kesamaan dari gesekan listrik dan petir pasti tambah semangat dengan upaya dari banyak peneliti di bidang ini dalam paruh terakhir abad ke-18, untuk memajukan 'kemajuan ilmu pengetahuan. [13] Franklin's pengamatan dibantu kemudian ilmuwan seperti Michael Faraday, Luigi Galvani, Alessandro Volta, André-Marie Ampere, dan Georg Simon Ohm yang bekerja memberikan dasar bagi teknologi listrik modern. Karya Faraday, Volta, Ampere, dan Ohm dihormati oleh masyarakat, dalam satuan-satuan dasar pengukuran listrik dinamai setelah mereka. Orang lain juga akan memajukan bidang pengetahuan, termasuk para pekerja Watson, Boze, Smeaton, Le Monnicr, De Romas, Jallabert, Beccaria, Cavallo, John Kanton, Robert Symmer, Nollet, Winckler, Richman, Dr Wilson, Kinnersley, Priestley, Aepinus , Délavai, Cavendish, Coulomb, Volta dan Galvani. Sebuah gambaran dari banyak percobaan dan penemuan awal ini pekerja di bidang ilmu dan seni listrik akan ditemukan dalam publikasi ilmiah dari waktu; terutama 'Philosophical Transactions, 1 Philosophical Magazine, Cambridge Mathematical Journal, Young's' Alam Filsafat , 'Priestley's' Sejarah Listrik, '' Franklin's 'Eksperimen dan Pengamatan tentang Ketenagalistrikan,' Cavalli's 'Treatise on Listrik,' De la Rive's 'Risalah tentang Ketenagalistrikan. " Elles Henry adalah salah satu orang pertama yang menunjukkan hubungan antara listrik dan magnetisme. Tahun 1757 ia mengklaim bahwa ia telah menulis surat kepada Royal Society pada tahun 1755 tentang hubungan antara listrik dan magnet, dan menyatakan bahwa "ada beberapa hal pada kekuatan magnet yang sangat mirip dengan listrik" tetapi dia "tidak dengan cara apapun pikir mereka sama ". Pada 1760 ia juga menyatakan bahwa pada tahun 1750 ia pertama "untuk berpikir bagaimana api listrik dapat menjadi penyebabnya guntur". [37] Di antara yang lebih penting dari listrik eksperimen dan penelitian pada periode ini adalah mereka Francis Aepinus, yang dicatat ilmuwan Jerman (1724-1802) dan Henry Cavendish di London, Inggris. [13] Untuk Aepinus adalah diberikan kredit telah pertama untuk memahami pandangan tentang hubungan timbal balik listrik dan magnet. Dalam karyanya 'Tentamen theoria Electricitatis et Magnetisme!,' Diterbitkan di Saint Petersburg, 1759. ia memberikan amplifikasi berikut Franklin teori, yang dalam beberapa fitur-fiturnya yang menyolok di masa kini sesuai dengan pandangan: "Partikel-partikel fluida listrik saling tolak, menarik dan tertarik oleh partikel-partikel dari semua benda dengan kekuatan yang berkurang dalam proporsi sebagai jarak meningkat; cairan listrik ada di dalam pori-pori tubuh; unobstructedly bergerak secara non-listrik (konduktor), tetapi kesulitan dalam bergerak dengan insulator; perwujudan listrik disebabkan oleh distribusi yang tidak seimbang cairan di dalam sebuah tubuh, atau pendekatan bermuatan tubuh tidak seimbang dengan cairan. " Aepinus merumuskan teori yang sesuai magnetisme kecuali bahwa dalam kasus fenomena magnetik cairan hanya bertindak atas partikel-partikel besi. Dia juga membuat banyak percobaan listrik, antara lain yang tampaknya menunjukkan bahwa dalam rangka mewujudkan efek listrik menjadi tourmalin mengharuskan dipanaskan sampai suhu antara 37,5 ° С dan 100 ° C. Bahkan, tourmalin tetap unelectrified ketika suhu seragam, tetapi memanifestasikan sifat-sifat listrik ketika suhu naik atau turun. Kristal yang memanifestasikan sifat-sifat listrik dengan cara ini disebut Pyro-listrik, antara yang selain tourmalin, adalah sulfat dari kina dan kuarsa. [13]

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Cavendish dipahami secara independen teori listrik hampir mirip dengan yang Aepinus. [38] Ia juga (1784) mungkin orang pertama yang menggunakan listrik untuk menghasilkan percikan ledakan hidrogen dan oksigen dalam proporsi yang tepat untuk menghasilkan air murni. Filsuf yang sama juga menemukan kapasitas induktif bahan dielektrik (isolator) dan sejak 1778 mengukur kapasitas induktif spesifik untuk lilin lebah dan bahan-bahan lain dengan perbandingan dengan kondensor udara. Tentang CA 1784 Coulomb, setelah yang ini bernama unit listrik kuantitas, merancang torsi keseimbangan, dengan cara yang ia temukan apa yang dikenal sebagai Hukum Coulomb; - Gaya yang diberikan di antara dua tubuh listrik kecil berbanding terbalik dengan kuadrat jarak ; bukan sebagai Aepinus dalam teori listrik telah diasumsikan, hanya terbalik sebagai jarak. Menurut teori yang dikemukakan oleh Cavendish "partikel menarik dan tertarik terbalik sebagai suatu kekuatan kurang jarak daripada batu." [13] Dengan penemuan, oleh percobaan Watson dan orang lain, bahwa listrik bisa ditransmisikan ke jarak, gagasan untuk membuat penggunaan praktis fenomena ini dimulai, sekitar 1753, untuk memikat pikiran "ingin tahu" orang, dan untuk tujuan ini saran mencari pekerjaan listrik dalam transmisi dibuat intelijen. Pertama dari metode yang dirancang untuk tujuan ini adalah mungkin bahwa karena Besage (1774). Metode ini di pekerjaan terdiri dari 24 kabel, terisolasi dari satu sama lain dan masing-masing yang memiliki bola empulur terhubung ke ujung jauh. Setiap kawat mewakili sebuah surat dari alfabet. Untuk mengirim pesan, kawat yang dikehendaki didakwa sejenak dengan listrik dari mesin listrik, lalu sesudah itu bola empulur tersambung ke kabel yang akan terbang keluar; dan dengan cara ini pesan-pesan yang ditransmisikan. Metode lain di mana gesekan telegraphing dipekerjakan listrik juga mencoba, beberapa di antaranya akan dijelaskan dalam artikel di telegraf. [13]

Sampai sekarang satu-satunya listrik yang dikenal adalah yang dikembangkan oleh gesekan atau menggosok, yang karena itu disebut gesekan listrik. Kita sekarang sampai pada era volta galvanik atau listrik. Volta menemukan bahwa reaksi kimia dapat digunakan untuk menciptakan bermuatan positif anoda dan bermuatan negatif katoda. Ketika sebuah konduktor itu terpasang di antara ini, yang perbedaan potensial listrik (juga dikenal sebagai tegangan) mengendarai sebuah arus di antara mereka melalui konduktor. Para beda potensial antara dua titik diukur dalam satuan volt sebagai pengakuan atas karya Volta. [13] Penyebutan pertama volta listrik, walaupun tidak diakui sebagai demikian pada waktu itu, mungkin dibuat oleh Sulzer pada tahun 1767, yang pada menempatkan cakram kecil seng di bawah lidah dan piringan kecil tembaga di atasnya, mengamati rasa yang aneh ketika logam masingmasing mereka menyentuh ujungnya. Sulzer berasumsi bahwa ketika logam datang bersama-sama mereka ditetapkan dalam getaran, ini yang bekerja pada saraf lidah, menghasilkan efek menyadarinya. Tahun 1790 Prof Luigi Galvani Alyisio Bologna pada satu kesempatan, ketika melakukan percobaan pada "hewan listrik," seperti yang disebutnya itu, yang perhatiannya telah diubah oleh bergerak-gerak kaki kodok di hadapan mesin listrik, diamati bahwa otot-otot katak yang digantung pada pagar besi oleh kait tembaga yang lulus melalui kolom dorsal hidup mengalami kejang-kejang asing tanpa sebab; mesin listrik yang saat ini tidak ada. [13] Untuk menjelaskan fenomena ini Galvani diasumsikan bahwa listrik dari jenis yang berlawanan ada pada saraf dan otot-otot katak, otot dan saraf yang merupakan lapisan bermuatan dari Leiden jar. Galvani menerbitkan hasil penemuannya, bersama-sama dengan hipotesis, yang sekaligus asyik perhatian para fisikawan pada waktu itu; yang paling terkemuka di antaranya, Alexander Volta, profesor fisika di Pavia, berpendapat bahwa hasil yang diamati oleh Galvani adalah karena ke dua logam, tembaga dan besi, bertindak sebagai "electromotors," dan bahwa otot-otot katak memainkan bagian dari sebuah konduktor, menyelesaikan rangkaian. Hal ini mendorong terjadinya diskusi panjang antara para penganut pandangan yang saling bertentangan; satu set pengikutnya memegang dengan Volta bahwa arus listrik adalah hasil dari kontak gaya gerak listrik pada kedua logam, yang lain mengatur modifikasi mengadopsi pandangan Galvani dan menyatakan bahwa arus karena kecenderungan kimia antara logam dan asam dalam tumpukan. Michael Faraday menulis dalam kata pengantar ke Experimental Researches, relatif terhadap pertanyaan apakah kontak metalik atau tidak produktif menjadi bagian dari listrik dari tumpukan volta: Saya melihat belum ada alasan untuk mengubah pendapat saya berikan; .. . tapi titik itu sendiri adalah begitu penting bahwa saya bermaksud pada kesempatan pertama memperbaharui penyelidikan, dan jika aku bisa, memberikan bukti-bukti baik di satu sisi atau sisi lain, tak terbantahkan bagi semua. "[13] Bahkan Faraday sendiri, bagaimanapun, tidak menyelesaikan kontroversi, dan sementara pandangan dari para pendukung di kedua sisi dari pertanyaan telah mengalami modifikasi, sebagai penyelidikan dan penemuan-penemuan berikutnya menuntut, sampai sekarang perbedaan pendapat pada titik-titik ini terus tanaman luar. Volta membuat berbagai eksperimen untuk mendukung teorinya dan pada akhirnya mengembangkan tumpukan atau baterai, [39] yang merupakan pendahulu dari semua baterai kimia berikutnya, dan memiliki manfaat yang membedakan menjadi sarana pertama yang terus-menerus berkepanjangan arus listrik yang dapat diperoleh . Volta dikomunikasikan deskripsi dari tumpukan ke Royal Society of London dan tidak lama kemudian Nicholson dan Cavendish (1780) menghasilkan dekomposisi air dengan menggunakan arus listrik, menggunakan tumpukan Volta sebagai sumber tenaga listrik. [13]

Abad ke-19 Awal tahun 1800-an Di tahun 1800 Alessandro Volta dibangun perangkat pertama untuk menghasilkan arus listrik yang besar, yang kemudian dikenal sebagai baterai listrik. Napoleon, informasi tentang karya-karyanya, pada tahun 1801 memanggilnya untuk kinerja perintah dari eksperimen. Dia menerima banyak medali dan hiasan, termasuk Légion d'honneur. Davy pada tahun 1806, mempekerjakan sebuah tumpukan volta sekitar 250 sel, atau pasangan, membusuk garam abu dan soda, yang menunjukkan bahwa zat ini adalah masing-masing oksida kalium dan natrium, yang sebelumnya logam telah diketahui. Eksperimeneksperimen ini adalah awal elektrokimia, penyelidikan yang mengambil Faraday, dan mengenai yang pada tahun 1833 dia mengumumkan hukum penting elektrokimia setara, yaitu.: "Kuantitas yang sama listrik - yaitu, arus listrik yang sama - terurai secara kimia setara dengan jumlah semua mayat yang melintasi; maka bobot elemen dipisahkan dalam elektrolit ini satu sama lain sebagai setara kimia. " Mempekerjakan 2.000 baterai elemen dari tumpukan volta Humphry Davy pada tahun 1809 memberikan demonstrasi publik pertama listrik busur cahaya, dengan menggunakan arang untuk tujuan tertutup dalam ruang hampa. [13] Somewhat singular to note, it was not until many years after the discovery of the voltaic pile that the sameness of annual and frictional electricity with voltaic electricity was clearly recognized and demonstrated. Thus as late as January 1833 we find Faraday writing [ 40 ] in a paper on the electricity of the electric ray . "After an examination of the experiments of Walsh , Ingenhousz , Henry Cavendish , Sir H. Davy , and Dr. Davy, no doubt remains on my mind as to the identity of the electricity of the torpedo with common (frictional) and voltaic electricity; and I presume that so little will remain on the mind of others as to justify my refraining from entering at length into the philosophical proof of that identity. The doubts raised by Sir Humphry Davy have been removed by his brother, Dr. Davy; the results of the latter being the reverse of those of the former. ... The general conclusion which must, I think, be drawn from this collection of facts (a table showing the similarity, of properties of the diversely named electricities) is, that electricity, whatever may be its source, is identical in its nature." [ 13 ] It is proper to state, however, that prior to Faraday's time the similarity of electricity derived from different sources was more than suspected. Thus, William Hyde Wollaston , [ 41 ] wrote in 1801: [ 42 ] "This similarity in the means by which both electricity and galvanism (voltaic electricity) appear to be excited in addition to the resemblance that has been traced between their effects shows that they are both essentially the same and confirm an opinion that has already been advanced by others, that all the differences discoverable in the effects of the latter may be owing to its being less intense, but produced in much larger quantity." In the same paper Wollaston describes certain experiments in which he uses very fine wire in a solution of sulphate of copper through which he passed electric currents from an electric machine. This is interesting in connection with the later day use of almost similarly arranged fine wires in electrolytic receivers in wireless, or radio-telegraphy. [ 13 ]

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In the first half of the 19th century many very important additions were made to the world's knowledge concerning electricity and magnetism. For example, in 1819 Hans Christian Ørsted of Copenhagen discovered the deflecting effect of an electric current traversing a wire upon- a suspended magnetic needle. [ 13 ] This discovery gave a clue to the subsequently proved intimate relationship between electricity and magnetism which was promptly followed up by Ampère who shortly thereafter (1821) announced his celebrated theory of electrodynamics, relating to the force that one current exerts upon another, by its electro-magnetic effects, namely: [ 13 ]

1. Two parallel portions of a circuit attract one another if the currents in them are flowing in the same direction, and repel one another if the currents flow in the opposite direction. 2. Two portions of circuits crossing one another obliquely attract one another if both the currents flow either towards or from the point of crossing, and repel one another if one flows to and the other from that point. 3. When an element of a circuit exerts a force on another element of a circuit, that force always tends to urge the latter in a direction at right angles to its own direction.

Hans Christian Ørsted

Professor Seebeck , of Berlin, in 1821 discovered that when heat is applied to the junction of two metals that had been soldered together an electric current is set up. This is termed Thermo-Electricity . Seebeck's device consists of a strip of copper bent at each end and soldered to a plate of bismuth. A magnetic needle is placed parallel with the copper strip. When the heat of a lamp is applied to the junction of the copper and bismuth an electric current is set up which deflects the needle. [ 13 ] Peltier in 1834 discovered an effect opposite to the foregoing, namely, that when a current is passed through a couple of dissimilar metals the temperature is lowered or raised at the junction of the metals, depending on the direction of the current. This is termed the Peltier "effect" . The variations of temperature are found to be proportional to the strength of the current and not to the square of the strength of the current as in the case of heat due to the ordinary resistance of a conductor. This latter is the C2R law, discovered experimentally in 1841 by the English physicist, Joule . In other words, this important law is that the heat generated in any part of an electric circuit is directly proportional to the product of the resistance of this part of the circuit and to the square of the strength of current flowing in the circuit. [ 13 ] In 1822 Sweiprger devised the first galvanometer . This instrument was subsequently much improved by Wilhelm Weber (1833). In 1825 William Sturgeon of Woolwich, England, invented the horseshoe and straight bar electromagnet, receiving therefor the silver medal of the Society of Arts. [ 43 ] In 1837 Gauss and Weber (both noted workers of this period) jointly invented a reflecting galvanometer for telegraph purposes. This was the forerunner of the Thomson reflecting and other exceedingly sensitive galvanometers once used in submarine signaling and still widely employed in electrical measurements. Arago in 1824 made the important discovery that when a copper disc is rotated in its own plane, and if a magnetic needle be freely suspended on a pivot over the disc, the needle will rotate with the disc. If on the other hand the needle is fixed it will tend to retard the motion of the disc. This effect was termed Arago's rotations. [ 13 ] Futile attempts were made by Babbage , Barlow , Herschel and others to explain this phenomenon. The true explanation was reserved for Faraday, namely, that electric currents are induced in the copper disc by the cutting of the magnetic lines of force of the needle, which currents in turn react on the needle. In 1827 Georg Simon Ohm announced the now famous law that bears his name, that is: Electromotive force = Current × Resistance

Faraday and Henry The discovery of electromagnetic induction was made almost simultaneously, although independently, by Michael Faraday and Joseph Henry . While Faraday's early results preceded those of Henry, Henry was first in his use of the transformer principle. Henry's discovery of self-induction and his work on spiral conductors using a copper coil were made public in 1835, just before those of Faraday. [ 44 ] [ 45 ] [ 46 ]

Joseph Henry

In 1831 began the epoch-making researches of Michael Faraday , the famous pupil and successor of Humphry Davy at the head of the Royal Institution, London, relating to electric and electromagnetic induction. Faraday's studies and researches extended from 1831 to 1855 and a detailed description of his experiments, deductions and speculations are to be found in his compiled papers, entitled Experimental Researches in Electricity.' Faraday was by profession a chemist. He was not in the remotest degree a mathematician in the ordinary sense — indeed it is a quest on if in all his writings there is a single mathematical formula. [ 13 ] Michael Faraday

The experiment which led Faraday to the discovery of Electric Induction was made as follows: He constructed what is now and was then termed an induction coil, the primary and secondary wires of which were wound on a wooden bobbin, side by side, and insulated from one another. In the circuit of the primary wire he placed a battery of approximately 100 cells. In the secondary wire he inserted a galvanometer. On making his first test he observed no results, the galvanometer remaining quiescent, but on increasing the length of the wires he noticed a deflection of the galvanometer in the secondary wire when the circuit of the primary wire was made and broken. This was the first observed instance of the development of electromotive force by electromagnetic induction. [ 13 ] He also discovered that induced currents are established in a second closed circuit when the current strength is varied in the first "wire, and that the direction of the current in the secondary circuit is opposite to that in the first circuit. Also that a current is induced in a secondary circuit when another circuit carrying a current is moved to and from the first circuit, and that the approach or withdrawal of a magnet to or from a closed circuit induces momentary currents in the latter. In short, within the space of a few months Faraday discovered by experiment virtually all the laws and facts now known concerning electro-magnetic induction and magneto-electric induction. Upon these discoveries, with scarcely an exception, depends the operation of the telephone, the dynamo machine, and incidental to the dynamo electric machine practically all the gigantic electrical industries of the world, including electric lighting , electric traction, the operation of electric motors for power purposes, and electro-plating , electrotyping , etc. [ 13 ] In his investigations of the peculiar manner in which iron filings arrange themselves on a cardboard or glass in proximity to the poles of a magnet, Faraday conceived the idea of magnetic "lines of force" extending from pole to pole of the magnet and along which the filings tend to place themselves. On the discovery being made that magnetic effects accompany the passage of an electric current in a wire, it was also assumed that similar magnetic lines of force whirled around the wire. For convenience and to account for induced electricity it was then assumed that when these lines of force are «cut" by a wire in passing across them or when the lines of force in rising and falling cut the wire, a current of electricity is developed, or to be more exact, an electromotive force is developed in the wire that sets up a current in a closed circuit. Faraday advanced what has been termed the molecular theory of electricity which assumes that electricity is the manifestation of a peculiar condition of the molecule of the body rubbed or the ether surrounding the body. Faraday also, by experiment, discovered paramagnetism and diamagnetism , namely, that all solids and liquids are either attracted or repelled by a magnet. For example, iron, nickel, cobalt, manganese, chromium, etc., are paramagnetic (attracted by magnetism), whilst other substances, such as bismuth, phosphorus, antimony, zinc, etc., are repelled by magnetism or are diamagnetic. [ 13 ] [ 47 ] Brugans of Leyden in 1778 and Le Baillif and Becquerel in 1827 had previously discovered diamagnetism in the case of bismuth and antimony. Faraday also rediscovered specific inductive capacity in 1837, the results of the experiments by Cavendish not having been published at that

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time. He also predicted [ 48 ] the retardation of signals on long submarine cables due to the inductive effect of the insulation of the cable, in other words, the static capacity of the cable. [ 13 ] The 25 years immediately following Faraday's discoveries of electric induction were fruitful in the promulgation of laws and facts relating to induced currents and to magnetism. In 1834 Lenz and Jacobi independently demonstrated the now familiar fact that the currents induced in a coil are proportional to the number of turns in the coil. Lenz also announced at that time the important law that, in all cases of electromagnetic induction the induced currents have such a direction that their reaction tends to stop the motion that produces them, a law that was perhaps deducible from Faraday's explanation of Arago's rotations. [ 13 ] In 1845 Joseph Henry , the American physicist, published an account of his valuable and interesting experiments with induced currents of a high order, showing that currents could be induced from the secondary of an induction coil to the primary of a second coil, thence to its secondary wire, and so on to the primary of a third coil, etc. [ 49 ]

Middle 1800s Up to the middle of the 19th century, indeed up to about 1870, electrical science was, it may be said, a sealed book to the majority of electrical workers. Prior to this time a number of handbooks had been published on electricity and magnetism, notably Aug de La Rive 's exhaustive 'Treatise on Electricity,' 1851 and (in the French) 1835; Beer's Einleitung in die Electrostatik , Wiedemann 's 'Galvanismus,' and Reiss ' 'Reibungsal-elektricitat.' But these works consisted in the main in details of experiments with electricity and magnetism, and but little with the laws and facts of those phenomena. Abria published the results of some researches into the laws of induced currents, but owing to their complexity of the investigation it was not productive of very notable results. [ 51 ] Around the mid-1800s, Fleeming Jenkin 's work on 'Electricity and Magnetism' and Clerk Maxwell's 'Treatise on Electricity and Magnetism' were published. [ 13 ]

"

The electromagnetic theory of light adds to the old undulatory theory an enormous province of transcendent interest and importance; it demands of us not merely an explanation of all the phenomena of light and radiant heat by transverse vibrations of an elastic solid called ether, but also the inclusion of electric currents, of the permanent magnetism of steel and lodestone , of magnetic force , and of electrostatic force , in a comprehensive ethereal dynamics ."

Buku-buku ini keberangkatan dari jalan dipukuli. As Jenkin states in the preface to his work the science of the schools was so dissimilar from that of the practical electrician that it was quite impossible to give students sufficient, or even approximately sufficient, textbooks. A student he said might have mastered De la Rive 's large and valuable treatise and yet feel as if in an unknown country and listening to an unknown tongue in the company of practical men. As another writer has said, with the coming of Jenkin's and Maxwell's books all — Lord Kelvin [ 50 ] impediments in the way of electrical students were removed, "the full meaning of Ohm's law becomes clear; electromotive force, difference of potential, resistance, current, capacity, lines of force, magnetization and chemical affinity were measurable, and could be reasoned about, and calculations could be made about them with as much certainty as calculations in dynamics". [ 13 ] [ 52 ]

"

About 1850 Kirchoff published his laws relating to branched or divided circuits. He also showed mathematically that according to the then prevailing electrodynamic theory, electricity would be propagated along a perfectly conducting wire with the velocity of light. Helmholtz investigated mathematically the effects of induction upon the strength of a current and deduced therefrom equations, which experiment confirmed, showing amongst other important points the retarding effect of self-induction under certain conditions of the circuit. [ 13 ] [ 53 ] In 1853 Sir William Thomson (later Lord Kelvin ) predicted as a result of mathematical calculations the oscillatory nature of the electric discharge of a condenser circuit. To Henry, however, belongs the credit of discerning as a result of his experiments in 1842 the oscillatory nature of the Leyden jar discharge. He wrote: [ 54 ] The phenomena require us to admit the existence of a principal discharge in one direction, and then several reflex actions backward and forward, each more feeble than the preceding, until the equilibrium is obtained. These oscillations were subsequently observed by Fcddersen (1857) who using a rotating concave mirror projected an image of the electric spark upon a sensitive plate, thereby obtaining a photograph of the spark which plainly indicated the alternating nature of the discharge. Sir William Thomson was also the discoverer of the electric convection of heat (the "Thomson" effect). He designed for electrical measurements of precision his quadrant and absolute electrometers. The reflecting galvanometer and siphon recorder, as applied to submarine cable signaling, are also due to him. [ 13 ] About 1876 Prof. HA Rowland of Baltimore demonstrated the important fact that a static charge carried around produces the same magnetic effects as an electric current. The Importance of this discovery consists in that it may afford a plausible theory of magnetism, namely, that magnetism may be the result of directed motion of rows of molecules carrying static charges. [ 13 ]

Sir William Thomson

After Faraday's discovery that electric currents could be developed in a wire by causing it to cut across the lines of force of a magnet, it was to be expected that attempts would be made to construct machines to'avail of this fact in the development of voltaic currents. [ 55 ] The first machine of this kind was due to Pixii, 1832. It consisted of two bobbins of iron wire, opposite which the poles of a horseshoe magnet were caused to rotate. As this produced in the coils of the wire an alternating current, Pixii arranged a commutating device (commutator) that converted the alternating current of the coils or armature into a direct current in the external circuit. This machine was followed by improved forms of magneto-electric machines due to Ritchie , Saxton , Clarke , Stohrer 1843, Nollet 1849, Shepperd 1856, Van Maldern , Siemens , Wilde and others. [ 13 ] A notable advance in the art of dynamo construction was made by Mr. SA Varley in 1866 [ 56 ] and by Dr. Charles William Siemens and Mr. Charles Wheatstone , [ 57 ] who independently discovered that when a coil of wire, or armature, of the dynamo machine is rotated between the poles (or in the "field") of an electromagnet, a weak current is set up in the coil due to residual magnetism in the iron of the electromagnet, and that if the circuit of the armature be connected with the circuit of the electromagnet, the weak current developed in the armature increases the magnetism in the field. This further increases the magnetic lines of force in which the armature rotates, which still further increases the current in the electromagnet, thereby producing a corresponding increase in the field magnetism, and so on, until the maximum electromotive force which the machine is capable of developing is reached. By means of this principle the dynamo machine develops its own magnetic field, thereby much increasing its efficiency and economical operation. Not by any means, however, was the dynamo electric machine perfected at the time mentioned. [ 13 ] In 1860 an important improvement had been made by Dr. Antonio Pacinotti of Pisa who devised the first electric machine with a ring armature. This machine was first used as an electric motor, but afterward as a generator of electricity. The discovery of the principle of the reversibility of the dynamo electric machine (variously attributed to Walenn 1860; Pacinotti 1864 ; Fontaine , Gramme 1873; Deprez 1881, and others) whereby it may be used as an electric motor or as a generator of electricity has been termed one of the greatest discoveries of the 19th century. [ 13 ] In 1872 the drum armature was devised by Heffner - Altneck . This machine in a modified form was subsequently known as the Siemens dynamo. These machines were presently followed by the Schuckert , Gulcher , Fein , Brush , Hochhausen , Edison and the dynamo machines of numerous other inventors. In the early days of dynamo machine construction the machines were mainly arranged as direct current generators, and perhaps the most important application of such machines at that time was in electro-plating, for which purpose machines of low voltage and large current strength were employed. [ 13 ] [ 58 ]

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Beginning about 1887 alternating current generators came into extensive operation and the commercial development of the transformer, by means of which currents of low voltage and high current strength are transformed to currents of high voltage and low current strength, and vice-versa, in time revolutionized the transmission of electric power to long distances. Likewise the introduction of the rotary converter (in connection with the "step-down" transformer) which converts alternating currents into direct currents (and vice-versa) has effected large economies in the operation of electric power systems. [ 13 ] [ 59 ] Before the introduction of dynamo electric machines, voltaic, or primary, batteries were extensively used for electro-plating and in telegraphy. There are two distinct types of voltaic cells, namely, the "open" and the "closed," or "constant," type. The open type in brief is that type which operated on closed circuit becomes, after a short time, polarized; that is, gases are liberated in the cell which settle on the negative plate and establish a resistance that reduces the current strength. After a brief interval of open circuit these gases are eliminated or absorbed and the cell is again ready for operation. Closed circuit cells are those in which the gases in the cells are absorbed as quickly as liberated and hence the output of the cell is practically uniform. The Leclanché and Daniell cells , respectively, are familiar examples of the "open" and "closed" type of voltaic cell. The "open" cells are used very extensively at present, especially in the dry cell form, and in annunciator and other open circuit signal systems. Batteries of the Daniell or "gravity" type were employed almost generally in the United States and Canada as the source of electromotive force in telegraphy before the dynamo machine became available, and still are largely used for this service or as "local" cells. Batteries of the "gravity" and the Edison-Lalande types are still much used in "closed circuit" systems. [ 13 ] In the late 19th century, the term luminiferous aether , meaning light-bearing aether , was the term used to describe a medium for the propagation of light . [ 60 ] The word aether stems via Latin from the Greek αιθήρ, from a root meaning to kindle, burn, or shine. It signifies the substance which was thought in ancient times to fill the upper regions of space, beyond the clouds.

Maxwell, Hertz, and Tesla In 1864 James Clerk Maxwell of Edinburgh announced his electromagnetic theory of light, which was perhaps the greatest single step in the world's knowledge of electricity. [ 61 ] Maxwell had studied and commented on the field of electricity and magnetism as early as 1855/6 when On Faraday's lines of force was read to the Cambridge Philosophical Society . The paper presented a simplified model of Faraday's work, and how the two phenomena were related. He reduced all of the current knowledge into a linked set of differential equations with 20 equations in 20 variables. This work was later published as On Physical Lines of Force in March 1861. [ 62 ] Around 1862, while lecturing at King's College, Maxwell calculated that the speed of propagation of an electromagnetic field is approximately that of the speed of light. He considered this to be more than just a coincidence, and commented " We can scarcely avoid the conclusion that light consists in the transverse undulations of the same medium which is the cause of electric and magnetic phenomena. " [ 63 ] Working on the problem further, Maxwell showed that the equations predict the existence of waves of oscillating James Clerk Maxwell electric and magnetic fields that travel through empty space at a speed that could be predicted from simple electrical experiments; using the data available at the time, Maxwell obtained a velocity of 310,740,000 m/s . In his 1864 paper A Dynamical Theory of the Electromagnetic Field , Maxwell wrote, The agreement of the results seems to show that light and magnetism are affections of the same substance, and that light is an electromagnetic disturbance propagated through the field according to electromagnetic laws . [ 64 ] As already noted herein Faraday, and before him, Ampère and others, had inklings that the luminiferous ether of space was also the medium for electric action. It was known by calculation and experiment that the velocity of electricity was approximately 186,000 miles per second; that is, equal to the velocity of light, which in itself suggests the idea of a relationship between -electricity and "light." A number of the earlier philosophers or mathematicians, as Maxwell terms them, of the 19th century, held the view that electromagnetic phenomena were explainable by action at a distance. Maxwell, following Faraday, contended that the seat of the phenomena was in the medium. The methods of the mathematicians in arriving at their results were synthetical while Faraday's methods were analytical. Faraday in his mind's eye saw lines of force traversing all space where the mathematicians saw centres of force attracting at a distance. Faraday sought the seat of the phenomena in real actions going on in the medium; they were satisfied that they had found it in a power of action at a distance on the electric fluids. [ 65 ] Both of these methods, as Maxwell points out, had succeeded in explaining the propagation of light as an electromagnetic phenomenon while at the same time the fundamental conceptions of what the quantities concerned are, radically differed. The mathematicians assumed that insulators were barriers to electric currents; that, for instance, in a Leyden jar or electric condenser the electricity was accumulated at one plate and that by some occult action at a distance electricity of an opposite kind was attracted to the other plate. Maxwell, looking further than Faraday, reasoned that if light is an electromagnetic phenomenon and is transmissible through dielectrics such as glass, the phenomenon must be in the nature of electromagnetic currents in the dielectrics. He therefore contended that in the charging of a condenser, for instance, the action did not stop at the insulator, but that some "displacement" currents are set up in the insulating medium, which currents continue until the resisting force of the medium equals that of the charging force. In a closed conductor circuit, an electric current is also a displacement of electricity. The conductor offers a certain resistance, akin to friction, to the displacement of electricity, and heat is developed in the conductor, proportional to the square of the current(as already stated herein), which current flows as long as the impelling electric force continues. This resistance may be likened to that met with by a ship as it displaces in the water in its progress. The resistance of the dielectric is of a different nature and has been compared to the compression of multitudes of springs, which, under compression, yield with an increasing back pressure, up to a point where the total back pressure equals the initial pressure. When the initial pressure is withdrawn the energy expended in compressing the "springs" is returned to the circuit, concurrently with the return of the springs to their original condition, this producing a reaction in the opposite direction. Consequently the current due to the displacement of electricity in a conductor may be continuous, while the displacement currents in a dielectric are momentary and, in a circuit or medium which contains but little resistance compared with capacity or inductance reaction, the currents of discharge are of an oscillatory or alternating nature. [ 66 ] Maxwell extended this view of displacement currents in dielectrics to the ether of free space. Assuming light to be the manifestation of alterations of electric currents in the ether, and vibrating at the rate of light vibrations, these vibrations by induction set up corresponding vibrations in adjoining portions of the ether, and in this way the undulations corresponding to those of light are propagated as an electromagnetic effect in the ether. Maxwell's electromagnetic theory of light obviously involved the existence of electric waves in free space, and his followers set themselves the task of experimentally demonstrating the truth of the theory. In 1887, Prof. Heinrich Hertz in a series of experiments proved the actual existence of such waves. The discovery of electric waves in space naturally led to the discovery and introduction in the closing years of the 19th century of wireless telegraphy , various systems of which are now in successful use on shipboard, lighthouses and shore and inland stations throughout the world, by means of which intelligence is transmitted across the widest oceans and large parts of continents.

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In 1891, notable additions to our knowledge of the phenomena of electromagnetic frequency and high potential current were contributed by Nikola Tesla . [ 67 ] Amongst the novel experiments performed by Tesla was to take in his hand a glass tube from which the air had been exhausted, then bringing his body into contact with a wire carrying currents of high potential, the tube was suffused with a pleasing bright glow. Another experiment was to grasp a bulb that was suspended from a single wire attached to a high potential, high frequency current circuit, when a platinum button within the bulb was brought to vivid incandescence, the experimenter at this time standing on an insulating platform. The frequency and potential involved in the experiments made by Tesla at this time were of the order of one or more million cycles and volts. For further information relative to these experiments the reader may be referred to Tesla's Experiments with Alternate Currents of High Potential and High Frequency . [ 13 ]

End of the century The theories regarding electricity were undergoing change at the end of the 19th Century. Indeed it may with truth Nikola Tesla, circa 1896 be said that the trend of all scientific investigation now leads to the conclusion that matter in its final analysis is electrical in its nature — in fact is electricity; the theory upon which this view is based being termed the electronic theory, or the electric theory of matter. [ 68 ] This theory (or better, hypothesis) in a word assumes that the atom of matter, so far from being indivisible, as assumed under the older theories, is made up of smaller bodies termed electrons, that these electrons are electrical in their nature, and consequently all matter ultimately is electrical, the atoms of the different elements of matter consisting of a certain number of electrons, thus, 700 in the hydrogen atom and 11,200 in the oxygen atom. This theory of matter in several of its important features is not altogether one of a day, nor is it due to the researches of one man or to the conception of one mind. Thus, as regards the view that the atom is not an indivisible particle of matter, but is made up of numerous electrons, many scientists have for years held that all the elements are modifications of a single hypothetical substance, protyle, "the undifferentiated material of the universe." Nor is the theory entirely new in its assumption that all matter is electrical. [ 13 ] The electron as a unit of charge in electrochemistry was posited by G. Johnstone Stoney in 1874, who also coined the term electron in 1894. Plasma was first identified in a Crookes tube , and so described by Sir William Crookes in 1879 (he called it "radiant matter"). [ 69 ] The place of electricity in leading up to the discovery of those beautiful phenomena of the Crookes Tube (due to Sir William Crookes), viz., Cathode rays, [ 70 ] and later to the discovery of Roentgen or X-rays , must not be overlooked, since without electricity as the excitant of the tube the discovery of the rays might have been postponed indefinitely. It has been noted herein that Dr. William Gilbert was termed the founder of electrical science. This must, however, be regarded as a comparative statement. [ 13 ] During the late 1890s a number of physicists proposed that electricity, as observed in studies of electrical conduction in conductors, electrolytes, and cathode ray tubes , consisted of discrete units, which were given a variety of names, but the reality of these units had not been confirmed in a compelling way. However, there were also indications that the cathode rays had wavelike properties. [ 13 ] Faraday, Weber , Helmholtz , Clifford and others had glimpses of this view; and the experimental works of Zeeman , Goldstein , Crookes, JJ Thomson and others had greatly strengthened this view. Over 35 years ago Weber predicted William Crookes that electrical phenomena were due to the existence of electrical atoms, the influence of which on one another depended on their position and relative accelerations and velocities. Helmholtz and others also contended that the existence of electrical atoms followed from Faraday's laws of electrolysis, and Johnstone Stoney, to whom is due the term "electron," showed that each chemical ion of the decomposed electrolyte carries a definite and constant quantity of electricity, and inasmuch as these charged ions are separated on the electrodes as neutral substances there must be an instant, however brief, when the charges must be capable of existing separately as electrical atoms; while in 1887, Clifford wrote: "There is great reason to believe that every material atom carries upon it a small electric current, if it does not wholly consist of this current." [ 13 ] In 1896 JJ Thomson performed experiments indicating that cathode rays really were particles, found an accurate value for their charge-to-mass ratio e/m, and found that e/m was independent of cathode material. He made good estimates of both the charge e and the mass m, finding that cathode ray particles, which he called "corpuscles", had perhaps one thousandth of the mass of the least massive ion known (hydrogen). He further showed that the negatively charged particles produced by radioactive materials, by heated materials, and by illuminated materials, were universal. The nature of the Crookes tube " cathode ray " matter was identified by Thomson in 1897. [ 71 ] In the late 1800s, the Michelson-Morley experiment was performed by Albert Michelson and Edward Morley at what is now Case Western Reserve University . It is generally considered to be the evidence against the theory of a luminiferous aether . The experiment has also been referred to as "the kicking-off point for the theoretical aspects of the Second Scientific Revolution." [ 72 ] Primarily for this work, Albert Michelson was awarded the Nobel Prize in 1907. Dayton Miller continued with experiments, conducting thousands of measurements and eventually developing the most accurate interferometer in the world at that time. Miller and others, such as Morley, continue observations and experiments dealing with the concepts. [ 73 ] A range of proposed aether-dragging theories could explain the null result but these were more complex, and tended to use arbitrary-looking coefficients and physical assumptions.

Thomson

[ 13 ]

By the end of the 19th century electrical engineers had become a distinct profession, separate from physicists and inventors. They created companies that investigated, developed and perfected the techniques of electricity transmission, and gained support from governments all over the world for starting the first worldwide electrical telecommunication network, the telegraph network . Pioneers in this field included Werner von Siemens , founder of Siemens AG in 1847, and John Pender , founder of Cable & Wireless . The late 19th century produced such giants of electrical engineering as Nikola Tesla , inventor of the polyphase induction motor . The first public demonstration of a "alternator system" took place in 1886. [ 74 ] [ 75 ] Large two-phase alternating current generators were built by a British electrician, JEH Gordon , in 1882. Lord Kelvin and Sebastian Ferranti also developed early alternators, producing frequencies between 100 and 300 hertz. In 1891, Nikola Tesla patented a practical "high-frequency" alternator (which operated around 15,000 hertz ). [ 76 ] After 1891, polyphase alternators were introduced to supply currents of multiple differing phases. [ 77 ] Later alternators were designed for varying alternating-current frequencies between sixteen and about one hundred hertz, for use with arc lighting, incandescent lighting and electric motors. [ 78 ] The possibility of obtaining the electric current in large quantities, and economically, by means of dynamo electric machines gave impetus to the development of incandescent and arc lighting. Until these machines had attained a commercial basis voltaic batteries were the only available source of current for electric lighting and power. The cost of these batteries, however, and the difficulties of maintaining them in reliable operation were prohibitory of their use for practical lighting purposes. The date of the employment of arc and incandescent lamps may be set at about 1877. [ 13 ] Even in 1880, however, but little headway had been made toward the general use of these illuminants; the rapid subsequent growth of this industry is a matter of general knowledge. [ 79 ] The employment of storage batteries , which were originally termed secondary batteries or accumulators, began about 1879. Such batteries are now utilized on a large scale as auxiliaries to the dynamo machine in electric powerhouses and substations, in electric automobiles and in immense numbers in automobile ignition and starting systems, also in fire alarm telegraphy and other signal systems. [ 13 ]

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In 1893, the World's Columbian International Exposition was held in a building which was devoted to electrical exhibits. General Electric Company (backed by Edison and JP Morgan ) had proposed to power the electric exhibits with direct current at the cost of one million dollars. However, Westinghouse, armed with Tesla's alternating current system, proposed to illuminate the Columbian Exposition in Chicago for half that price, and Westinghouse won the bid. It was an historical moment and the beginning of a revolution, as Nikola Tesla and George Westinghouse introduced the public to electrical power by illuminating the Exposition. World's Fair Tesla presentation

Revolusi Industri Kedua Artikel utama: Revolusi Industri Kedua The AC motor helped usher in the Second Industrial Revolution . The rapid advance of electrical technology in the latter 19th and early 20th centuries led to commercial rivalries. In the War of Currents in the late 1880s, George Westinghouse and Thomas Edison became adversaries due to Edison's promotion of direct current (DC) for electric power distribution over alternating current (AC) advocated by Westinghouse and Nikola Tesla . Tesla's patents and theoretical work formed the basis of modern alternating current electric power (AC) systems, including the polyphase power distribution systems. [ 80 ] [ 81 ] Several inventors helped develop commercial systems. Samuel Morse , inventor of a long-range telegraph; Thomas Edison , inventor of the first commercial electrical energy distribution network; George Westinghouse , inventor of the electric locomotive ; Alexander Graham Bell , the inventor of the telephone and founder of a successful telephone business. In 1871 the electric telegraph had grown to large proportions and was in use in every civilized country in the world, its lines forming a network in all directions over the surface of the land. The system most generally in use was the electromagnetic telegraph due to SFB Morse of New York, or modifications of his system. [ 82 ] Submarine cables [ 83 ] connecting the Eastern and Western hemispheres were also in successful operation at that time. [ 13 ]

Thomas Edison

When, however, in 1918 one views the vast applications of electricity to electric light, electric railways, electric power and other purposes (all it may be repeated made possible and practicable by the perfection of the dynamo machine), it is difficult to believe that no longer ago than 1871 the author of a book published in that year, in referring to the state of the art of applied electricity at that time, could have truthfully written: "The most important and remarkable of the uses which have been made of electricity consists in its application to telegraph purposes". [ 84 ] The statement was, however, quite accurate and perhaps the time could have been carried forward to the year 1876 without material modification of the remarks. In that year the telephone , due to Alexander Graham Bell , was invented, but it was not until several years thereafter that its commercial employment began in earnest. Since that time also the sister branches of electricity just mentioned have advanced and are advancing with such gigantic strides in every direction that it is difficult to place a limit upon their progress. For a more adequate account of the use of electricity in the arts and industries. [ 13 ] [ 85 ] AC replaced DC for central station power generation and power distribution, enormously extending the range and improving the safety and efficiency of power distribution. Edison's low-voltage distribution system using DC ultimately lost to AC devices proposed by others: primarily Tesla's polyphase systems, and also other contributors, such as Charles Proteus Steinmetz (in 1888, he was working in Pittsburgh for Westinghouse [ 86 ] ). The successful Niagara Falls system was a turning point in the acceptance of alternating current. Eventually, the General Electric company (formed by a merger between Edison's companies and the AC-based rival Thomson-Houston ) began manufacture of AC machines. Centralized power generation became possible when it was recognized that alternating current electric power lines can transport electricity at low costs across great distances by taking advantage of the ability to change voltage across the distribution path using power transformers. The voltage is raised at the point of generation (a representative number is a generator voltage in the low kilovolt range) to a much higher voltage (tens of thousands to several hundred thousand volts) for primary transmission, followed to several downward transformations, to as low as that used in residential domestic use. [ 13 ]

Charles Proteus Steinmetz, theoretician of alternating current.

The International Electro-Technical Exhibition of 1891 featuring the long distance transmission of high-power, three-phase electrical current. It was held between 16 May and 19 October on the disused site of the three former “Westbahnhöfe” (Western Railway Stations) in Frankfurt am Main. The exhibition featured the first long distance transmission of high-power, three-phase electrical current, which was generated 175 km away at Lauffen am Neckar. As a result of this successful field trial, three-phase current became established for electrical transmission networks throughout the world. [ 13 ] Much was done in the direction in the improvement of railroad terminal facilities, and it is difficult to find one steam railroad engineer who would have denied that all the important steam railroads of this country were not to be operated electrically. In other directions the progress of events as to the utilization of electric power was be expected to be equally rapid. In every part of the world the power of falling water, nature's perpetual motion machine, which has been going to waste since the world began, is now being converted into electricity and transmitted by wire hundreds of miles to points where it is usefully and economically employed. [ 13 ] [ 87 ] The extensive utilization of falling water was not limited to natural water falls. In hundreds of places where a fall of 40 to 400 feet extends over 10 to 50 miles, and where in the aggregate hundreds of thousands of horse power, by suitable hydraulic methods, are available, the power was usefully employed, thereby in large measure conserving the limited quantity of the world's coal. It has for instance been proposed to dam Niagara River at the foot of the gorge whereby another source of water power equal to that at the present falls would be available. The Jchlun River in Kashmir, India, too, has a fall of 2,480 feet in 80 miles with a minimum flow of 30,000 gallons per second, and a beginning has been made to develop the 1,000,000 electric horse power here represented, я considerable portion of which it is proposed to utilize in the production of nitrate of lime for fertilizer purposes, by combining by means of powerful electric currents the limestone that abounds in this region with the nitrogen of the air, a combination which Danish engineers have shown to be commercially possible, and which inexhaustible product may in time be economically available to replenish the failing powers of the farm lands of America and other countries. The dreams of the electrical engineer was that the direct production of electricity from coal without the intervention of the steam engine with its wasteful methods was to be realized. [ 13 ] The first windmill for electricity production was built in Scotland in July 1887 by Prof James Blyth of Anderson's College , Glasgow (the precursor of Strathclyde University. [ 88 ] Across the Atlantic, in Cleveland, Ohio a larger and heavily engineered machine was designed and constructed in 1887-1888 by Charles F. Brush , [ 89 ] this was built by his engineering company at his home and operated from 1886 until 1900. [ 90 ] The Brush wind turbine had a rotor 56 feet (17 m) in diameter and was mounted on a 60-foot (18 m) tower. Although large by today's standards, the machine was only rated at 12 kW; it turned relatively slowly since it had 144 blades. The connected dynamo was used either to charge a bank of batteries or to operate up to 100 incandescent light bulbs , three arc lamps, and various motors in Brush's laboratory. The machine fell into disuse after 1900 when electricity became available from Cleveland's central stations, and was abandoned in 1908. [ 91 ]

Abad ke-20 Various units of electricity and magnetism have been adopted and named by representatives of the electrical engineering institutes of the world, which units and names have been confirmed and legalized by the governments of the United States and other countries. Thus the volt,

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from the Italian Volta, has been adopted as the practical unit of electromotive force, the ohm, from the enunciator of Ohm's law, as the practical unit of resistance; the ampere, after the eminent French scientist of that name, as the practical unit of current strength, the henry as the practical unit of inductance, after Joseph Henry and in recognition of his early and important experimental work in mutual induction. [ 92 ]

Lorentz and Poincaré Main articles: History of special relativity and Lorentz ether theory Between 1900 and 1910, many scientists like Wilhelm Wien , Max Abraham , Hermann Minkowski , or Gustav Mie believed that all forces of nature are of electromagnetic origin (the so called "electromagnetic world view"). This was connected with the electron theory developed between 1892 and 1904 by Hendrik Lorentz . Lorentz introduced a strict separation between matter (electrons) and ether, whereby in his model the ether is completely motionless, and it won't be set in motion in the neighborhood of ponderable matter. Contrary to other electron models before, the electromagnetic field of the ether appears as a mediator between the electrons, and changes in this field can propagate not faster than the speed of light. Lorentz theoretically explained the Zeeman effect on the basis of his theory, for which he received the Nobel Prize in Physics in 1902. A fundamental concept of Lorentz's theory in 1895 was the "theorem of corresponding states" for terms of order v/c. This theorem states that a moving observer (relative to the ether) in his "fictitious" field makes the same observations as a resting observers in his "real" field. This theorem was extended for terms of all orders by Lorentz in 1904. Lorentz noticed, that it was necessary to change the space-time variables when changing frames and introduced concepts like physical length contraction (1892) to explain the Michelson-Morley experiment, and the mathematical concept of local time (1895) to explain the aberration of light and the Fizeau experiment . That resulted in the formulation of the so called Lorentz transformation by Joseph Larmor (1897, 1900) and Lorentz (1899, 1904). [ 93 ] [ 94 ] [ 95 ]

Hendrik Lorentz

Continuing the work of Lorentz, Henri Poincaré between 1895 and 1905 formulated on many occasions the Principle of Relativity and tried to harmonize it with electrodynamics. He declared simultaneity only a convenient convention which depends on the speed of light, whereby the constancy of the speed of light would be a useful postulate for making the laws of nature as simple as possible. In 1900 he interpreted Lorentz's local time as the result of clock synchronization by light signals, and introduced the electromagnetic momentum by ascribing to electromagnetic 2 energy the "fictitious" mass m = E / c . And finally in June and July 1905 he declared the relativity principle a general law of nature, including gravitation. He corrected some mistakes of Lorentz and proved the Lorentz covariance of the electromagnetic equations. Poincaré also found out that there exist non-electrical forces to stabilize the electron configuration and asserted that gravitation is a non-electrical force as well. So the electromagnetic world view was shown by Poincaré to be invalid. However, he remained the notion of an ether and still distinguished between "apparent" and "real" time and therefore failed to invent what is now called special relativity . [ 95 ] [ 96 ] [ 97 ] [ 98 ] [ 99 ] [ 100 ]

Einstein's Annus Mirabilis

Henri Poincaré

Artikel utama: Annus mirabilis Papers In 1905, while he was working in the patent office, Albert Einstein had four papers published in the Annalen der Physik , the leading German physics journal. These are the papers that history has come to call the Annus Mirabilis Papers : His paper on the particulate nature of light put forward the idea that certain experimental results, notably the photoelectric effect , could be simply understood from the postulate that light interacts with matter as discrete "packets" ( quanta ) of energy, an idea that had been introduced by Max Planck in 1900 as a purely mathematical manipulation, and which seemed to contradict contemporary wave theories of light ( Einstein 1905a ). This was the only work of Einstein's that he himself called "revolutionary." His paper on Brownian motion explained the random movement of very small objects as direct evidence of molecular action, thus supporting the atomic theory . ( Einstein 1905b ) His paper on the electrodynamics of moving bodies introduced the radical theory of special relativity , which showed that the observed independence of the speed of light on the observer's state of motion required Albert Einstein, 1905 fundamental changes to the notion of simultaneity . Konsekuensi dari perbuatan ini termasuk kerangka waktu-ruang dari benda yang bergerak melambat dan kontraktor (dalam arah gerakan) relatif terhadap kerangka pengamat. This paper also argued that the idea of a luminiferous aether —one of the leading theoretical entities in physics at the time—was superfluous. ( Einstein 1905c ) In his paper on mass–energy equivalence (previously considered to be distinct concepts), Einstein deduced from his equations of special 2 relativity what later became the well-known expression: E = m c , suggesting that tiny amounts of mass could be converted into huge amounts of energy. ( Einstein 1905d ) All four papers are today recognized as tremendous achievements—and hence 1905 is known as Einstein's " Wonderful Year ". Pada waktu itu, bagaimanapun, mereka tidak diperhatikan oleh kebanyakan fisikawan sebagai penting, dan banyak dari mereka yang memang melihat mereka menolak mereka mentah-mentah. Some of this work—such as the theory of light quanta—remained controversial for years. [ 101 ] [ 102 ]

Abad ke-21 There are a range of emerging energy technologies .

Wireless electricity Main article: wireless energy transfer "Wireless electricity" describes a form of wireless energy transfer , the ability to provide electrical energy to remote objects without wires. The term WiTricity was coined in 2005 by Dave Gerding and later used for a project led by Prof. Marin Soljačić in 2007. [ 103 ] [ 104 ] The MIT researchers successfully demonstrated the ability to power a 60 watt light bulb wirelessly, using two 5-turn copper coils of 60 cm (24 in) diameter , that were 2 m (7 ft) away, at roughly 45% efficiency. [ 105 ] This technology can potentially be used in a large variety of applications, including consumer, industrial, medical and military. Its aim is to reduce the dependence on batteries. Further applications for this technology include transmission of information —it would not interfere with radio waves and thus could be used as a cheap and efficient communication device without requiring a license or a government permit. Further information: WiTricity

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Electromagnetism , Electricity , Electromotive force , Ponderomotive force , Electric charge , World's Columbian Exposition , alternating current and direct current , Electric current , amperes , Magnetic field , Diamagnetic , volts , Electron , electrode , Static electricity , Telluric currents , Terrestrial magnetism , electrification , Electromagnetic waves , magnetic force , electrolysis , ampere-hours , Transverse waves , Longitudinal waves , Plane waves , Electric force , Refractive index , Chemical affinity , torque , Magnetic induction , Leyden jar , potential difference , Revolutions per minute , electric force , Photosphere , Magnetic moment , Vortex , vortex rings , dielectric , Teori Force H , permittivity , quaternion , scalar product , vector product , tensor , vector algebra , divergent series , linear operator , unit vector , parallelepiped , osculating plane , Ohm's law , standard candle Teknologi Electrostatic generator and patents , Galvanometer , Solenoid , electro-magnets , Nicol prisms , Baghdad Battery , Arc lamps , rheostat , Armature , dynamo , arc lights , incandescent lamps , voltmeter , gutta-percha covered wire , Electrical conductor , ammeters , induction coil , Gramme machine , binding posts , Induction motor , Lightning arresters , Technological and industrial history of the United States , Western Electric Company , Siemens , Tesla motors Daftar List of basic energy development topics Timelines Timeline of electromagnetism , Timeline of luminiferous aether Orang-orang Nikola Tesla , Ernst Werner von Siemens , Heinrich Hertz , Thomas Edison

Referensi Kutipan dan catatan

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1. ^ Bruno Kolbe, Francis ed Legge, Joseph Skellon, tr., " An Introduction seventeenth century, which substance is meant. It appears not at all to Electricity (http://translate.googleusercontent.com unlikely that the English were then much more familiar with the /translate_c?hl=id&sl=en&u=http://books.google.com attraction of jet than they were with that of amber. /books%3Fvid%3D0o90G64Z2FDIyKUsLs9%26id%3D150IAAAAIAAJ& 10. ^ The Phoenicians have transmitted to us in their romantic language the prev=/search%3Fq story that the pieces of Amber sometimes washed up by the waves of %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26sa%3DG& the ocean were the petrified tears of maidens, who, disappointed in rurl=translate.google.co.id& love, had cast themselves into the arms of Mother Ocean and had after usg=ALkJrhj3m4xecNFunRRhZXbbRYD15YBXlQ) ". Kegan Paul, Trench, years returned like Galatea to their original source. Trübner, 1908. 429 pages. Page 391 11. ^ Barrett, JP (1894). Electricity at the Columbian Exposition, including (http://translate.googleusercontent.com/translate_c?hl=id&sl=en& an account of the exhibits in the Electricity Building, the power plant in u=http://books.google.com Machinery Hall, the arc and incandescent lighting of the grounds and /books%3Fid%3D150IAAAAIAAJ%26printsec%3Dtitlepage%26source%3Dgbs_summary_r%26cad%3D0& buildings (http://translate.googleusercontent.com/translate_c?hl=id& prev=/search%3Fq sl=en&u=http://books.google.com/books%3Fid%3DlF5KAAAAMAAJ& %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26sa%3DG& prev=/search%3Fq rurl=translate.google.co.id& %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26sa%3DG& usg=ALkJrhiqQx_RItivN9N3GwPjqT8HNgFUMg#PPA391,M1) . (cf., "[...] rurl=translate.google.co.id& high poles covered with copper plates and with gilded tops were erected usg=ALkJrhgqQt0w0bXGkj90a9C7vQlqU5NM4w) ... etc. Chicago: RR 'to break the stones coming from on high'. J. Dümichen, Baugeschichte Donnelley. Halaman 4 des Dendera-Tempels, Strassburg, 1877") 12. ^ a b c Benjamin, P. (1898). A history of electricity (The intellectual rise 2. ^ Urbanitzky, A. v., & Wormell, R. (1886). Electricity in the service of in electricity) from antiquity to the days of Benjamin Franklin. New York: man: a popular and practical treatise on the applications of electricity in J. Wiley & Sons. modern life (http://translate.googleusercontent.com/translate_c?hl=id& 13. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak sl=en&u=http://books.google.com/books%3Fid%3DrkgOAAAAYAAJ& al am an ao ap aq ar as at au av aw ax ay az ba bb bc bd be bf bg bh The prev=/search%3Fq Encyclopedia Americana; a library of universal knowledge. (1918). New %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26sa%3DG& York: Encyclopedia Americana Corp rurl=translate.google.co.id& 14. ^ Heinrich Karl Brugsch-Bey and Henry Danby Seymour, " A History of usg=ALkJrhgutW62nMpESGrZcZ5LF3Hc38AgPw) . London: Cassell &. Egypt Under the Pharaohs (http://translate.googleusercontent.com 3. ^ Lyons, TA (1901). A treatise on electromagnetic phenomena, and on /translate_c?hl=id&sl=en&u=http://books.google.com the compass and its deviations aboard ship. Mathematical, theoretical, /books%3Fvid%3D0CJl3KVQupibKmzuADNu17%26id%3DLoiTizgRo9kC& and practical. New York: J. Wiley & Sons. prev=/search%3Fq 4. ^ The Encyclopaedia Britannica; a dictionary of arts, sciences and %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26sa%3DG& general literature. (1890). New York: The Henry G. Allen Company. rurl=translate.google.co.id& 5. ^ a b c Whittaker, ET (1910). A history of the theories of aether and usg=ALkJrhgTs8FlJSK4sOM9BrHUVZEv20xYGw) ". J. Murray, 1881. Page electricity from the age of Descartes to the close of the nineteenth 422. (cf., [... the symbol of a] 'serpent' is rather a fish, which still century. Dublin University Press series. London: Longmans, Green and serves, in the Coptic language, to designate the electric fish [...]) Co.; [etc.]. 15. ^ Seeman, Bernard and Barry, James E. The Story of Electricity and 6. ^ Carlson, p. 753–760 Magnetism , Harvey House 1967, p. 19 7. ^ Lodestone Compass: Chinese or Olmec Primacy?: Multidisciplinary 16. ^ Moller, Peter (Desember 1991), "Review: Electric Ikan", Bioscience analysis of an Olmec hematite artifact from San Lorenzo, Veracruz, 41 (11): 794-6 [794], doi: 10.2307/1311732 Mexico - Carlson 189 (4205): 753 - Science (http://translate.googleusercontent.com/translate_c?hl=id&sl=en& (http://translate.googleusercontent.com/translate_c?hl=id&sl=en& u=http://dx.doi.org/10.2307%252F1311732&prev=/search%3Fq u=http://www.sciencemag.org/cgi/content/abstract/189/4205 %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26 /753&prev=/search%3Fq sa%3DG&rurl=translate.google.co.id& %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26sa%3DG& usg=ALkJrhhiLhqlg6TlbcqS50ChgJoLUZvmgQ) rurl=translate.google.co.id&usg=ALkJrhhP7Va47EtDtFNgonMBnV17. ^ Bullock, Theodore H. (2005), Electroreception , Springer, pp. 5–7, riER-tw) ISBN 0387231927 8. ^ Li Shu-hua, hal 175 18. ^ Morris, Simon C. (2003), Life's Solution: Inevitable Humans in a 9. ^ If there was another substance, having the same attractive quality as Lonely Universe , Cambridge University Press, pp. 182–185, ISBN the amber, was known to the ancients, it was probably jet — a species 0521827043 of lignite resembling cannel coal, but harder and susceptible of a high 19. ^ Riddle of 'Baghdad's batteries'. polish. It does not seem possible, however, to resolve that doubt, owing (http://translate.googleusercontent.com/translate_c?hl=id&sl=en& to the many kinds of coal and other fossil deposits which not only old u=http://news.bbc.co.uk/1/hi/sci/tech/2804257.stm&prev=/search%3Fq writers but even modern commentators constantly confuse. %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26sa%3DG& Theophrastus speaks of a material which is plainly anthracite coal, and rurl=translate.google.co.id& Pliny (xxxvi. 18), of the Gagates, his description of which answers usg=ALkJrhj1BYGi2rPRpWJsnV6s3ZHF_fO9jg) BBC News. generally to that of jet; but neither author mentions any phenomenon 20. ^ After the Second World War , Willard Gray demonstrated current similar to that of the amber as pertaining to it. Later writers apply the production by a reconstruction of the inferred battery design when filled word "gagates" to almost any black bituminous material, though they with grape juice. W. Jansen experimented with benzoquinone (some commonly mean "jet" by the term. Leonardus regards the gagate as beetles produce quinones ) and vinegar in a cell and got satisfactory another species of amber — "black amber" — in contradistinction to performance. yellow, and he describes it as "black, light, dry and lucid, not 21. ^ An alternative, but still electrical explanation was offered by Paul transparent, and if put into fire has, as it were, the smell of pitch. Being Keyser. It was suggested that a priest or healer, using an iron spatula to heated with rubbing it attracts straws and chaff." Marbodeus gives compound a vinegar based potion in a copper vessel, may have felt an almost the same account and states that it is found in Britain, where it is electrical tingle, and used the phenomenon either for electrostill obtained in the tertiary clays along the Yorkshire coast. This acupuncture, or to amaze supplicants by electrifying a metal statue. unfortunate confusion of yellow amber and jet, probably first due to 22. ^ Copper and iron form an electrochemical couple, so that in the Leonardus, has rendered it impossible to tell, from the references to presence of any electrolyte , an electric potential (voltage) will be amber attraction by the writers of the sixteenth and even of the produced. König had observed a number of very fine silver objects from

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ancient Iraq which were plated with very thin layers of gold, and %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26sa%3DG& speculated that they were electroplated using batteries of these "cells". rurl=translate.google.co.id& ^ Corder, Gregory, "Using an Unconventional History of the Battery to usg=ALkJrhhpa7KRbmVj1Ha8abuAgmiMsAVqPA) engage students and explore the importance of evidence", Virginia 70. ^ consult 'Proc. British Association,' 1879 Journal of Science Education 1 71. ^ Announced in his evening lecture to the Royal Institution on Friday, 30 ^ His Epistola was written in 1269. April 1897, and published in Philosophical Magazine , 44, 293 [3] ^ consult ' Priestley's 'History of Electricity,' London 1757 (http://translate.googleusercontent.com/translate_c?hl=id&sl=en& ^ Consult Boyle's 'Experiments on the Origin of Electricity,'" and u=http://web.lemoyne.edu/%7EGIUNTA/thomson1897.html& Priestley's 'History of Electricity'. prev=/search%3Fq ^ Consult Dr. Carpue 's 'Introduction to Electricity and Galvanism,' %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26sa%3DG& London 1803. rurl=translate.google.co.id&usg=ALkJrhhH9uhr3taTp3_^ Krebs, Robert E. (2003). Groundbreaking Scientific Experiments, Hf8A7hsbFZefkA) Inventions, and Discoveries of the 18th Century . Greenwood Publishing 72. ^ Earl R. Hoover, Cradle of Kehebatan: Nasional dan World Prestasi dari Group. p. 82. ISBN 0-313-32015-2 . Ohio's Western Reserve (Cleveland: Shaker Savings Association, 1977). ^ Keithley, Joseph F. (1999). The Story of Electrical and Magnetic 73. ^ Dayton C. Miller, "Ether-drift Experiments at Mount Wilson Solar Measurements: From 500 BC to the 1940s . Wiley. ISBN 0-780-31193-0 Observatory," Physics Review (http://translate.googleusercontent.com . /translate_c?hl=id&sl=en&u=http://prola.aps.org/abstract/PR/v19 ^ According to Priestley ('History of Electricity,' 3d ed., Vol. I, p. 102) /i4/p407_1&prev=/search%3Fq ^ Priestley's 'History of Electricity,' p. 138 %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26sa%3DG& ^ 'Philosophical Transactions.' hal 786, 1754 rurl=translate.google.co.id& ^ See also article electrotherapeutics . usg=ALkJrhj071qk1iuu6ozA_A2vuuYttmfkEA) , S2, V19, N4, pp. 407-408 ^ Socket to me! How electricity came to be. (April 1922). (http://translate.googleusercontent.com/translate_c?hl=id&sl=en& 74. ^ Alternating current generating systems were known in simple forms u=http://www.ieee-virtual-museum.org/exhibit from the discovery of the magnetic induction of electric current . The /exhibit.php%3Fid%3D159249%26lid%3D1&prev=/search%3Fq early machines were developed by pioneers such as Michael Faraday %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26sa%3DG& and Hippolyte Pixii . Faraday developed the "rotating rectangle", whose rurl=translate.google.co.id& operation was heteropolar - each active conductor passed successively usg=ALkJrhhnCpH2WwiBze1hdgMhlmDHkQnocw) (2007). IEEE Virtual through regions where the magnetic field was in opposite directions. History Museum. 75. ^ Blalock, Thomas J., " Alternating Current Electrification, 1886 ^ see atmospheric electricity (http://translate.googleusercontent.com/translate_c?hl=id&sl=en& ^ Franklin, 'Experiments and Observations on Electricity' u=http://www.ieee.org/organizations/history_center/stanley.html& ^ Royal Society Papers, vol. IX (BL. Add MS 4440): Henry Elles, from prev=/search%3Fq Lismore, Ireland, to the Royal Society, London, 9 August 1757, f.12b; 9 %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26sa%3DG& August 1757, f.166. rurl=translate.google.co.id& ^ Philosophical Transactions 1771 usg=ALkJrhhMtlV1ri8Ss9oTPfFXucGXarKK1w) ". Pusat Sejarah IEEE, ^ See Voltaic pile IEEE Milestone. ( ed . first practical demonstration of a dc generator - ac ^ 'Philosophical Transactions,' 1833 transformer system.) ^ another noted and careful experimenter in electricity and the 76. ^ US patent 447921 (http://translate.googleusercontent.com discoverer of palladium and rhodium /translate_c?hl=id&sl=en&u=http://v3.espacenet.com ^ Philosophical Magazine, Vol. Ill, p. 211 /textdoc%3FDB%3DEPODOC%26IDX%3DUS447921&prev=/search%3Fq ^ 'Trans. Society of Arts,1 1825 %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26sa%3DG& ^ Tsverava, GK 1981. "FARADEI, GENRI, I OTKRYTIE rurl=translate.google.co.id& INDUKTIROVANNYKH TOKOV." Voprosy Istorii Estestvoznaniia i Tekhniki usg=ALkJrhiivM88rWJr8QaSXNWHJ6aLxAiSrQ) , Tesla, Nikola, no. 3: 99-106. Historical Abstracts, EBSCOhost (accessed October 17, "Alternating Electric Current Generator". 2009). 77. ^ Thompson, Silvanus P., Dynamo-Electric Machinery . hal. 17 ^ Bowers, Brian. 2004. "Barking Up the Wrong (Electric Motor) Tree." 78. ^ Thompson, Silvanus P., Dynamo-Electric Machinery . hal. 16 Proceedings of the IEEE 92, no. 2: 388-392. Computers & Applied 79. ^ See electric lighting Sciences Complete, EBSCOhost (accessed October 17, 2009). 80. ^ Lomas, Robert (1999). The Man who Invented the Twentieth Century. ^ 1998. "Joseph Henry." Issues in Science & Technology 14, no. 3: 96. London: Headline. ISBN 0747275882 . Associates Programs Source, EBSCOhost (accessed October 17, 2009). 81. ^ See War of Currents and International Electro-Technical Exhibition ^ 'Phil. Trans.,' 1845. 1891 ^ Phil. Mag-., March 1854 82. ^ See telegraph ^ Philosophical Magazine, 1849. 83. ^ see transatlantic cable ^ Lyons, TA (1901). A treatise on electromagnetic phenomena, and on 84. ^ Miller's 'Magnetism and Electricity,' p. 460 the compass and its deviations aboard ship. Mathematical, theoretical, 85. ^ See Electrical manufacturing industry and practical. New York: J. Wiley & Sons. Page 500. 86. ^ Thomas Hughes, Networks of Power , page 120 ^ 'Ann. de Chimie III,' i, 385. 87. ^ See Electric transmission of energy . ^ Introduction to 'Electricity in the Service of Man'. 88. ^ 'James Blyth - Britain's first modern wind power pioneer', by Trevor ^ 'Poggendorf Ann.1 1851. Price, 2003, Wind Engineering, vol 29 no. 3, pp 191-200] ^ Proc. Am. Phil. Soc.,Vol. II, hlm. 193 89. ^ [Anon, 1890, 'Mr Sikat's Windmill Dynamo ", Scientific American, vol ^ (See electric machinery , electric direct current , electrical generators 63 no. 25, 20 December, p. 54] ) 90. ^ Sebuah Energi Angin Pioneer: Charles F. Brush, ^ consult his British patent of that year (http://translate.googleusercontent.com/translate_c?hl=id&sl=en& ^ consult 'Royal Society Proceedings, 1867 VOL. 10—12 u=http://www.windpower.org/en/pictures/brush.htm& ^ See electric direct current . prev=/search%3Fq ^ See Electric alternating current machinery. %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26sa%3DG& ^ The 19th century science book A Guide to the Scientific Knowledge of rurl=translate.google.co.id&usg=ALkJrhiYpTn4UK4BKNZThings Familiar provides a brief summary of scientific thinking in this CwUCGKvxGqMFYw) Denmark Angin Industry Association. Diperoleh field at the time. 2007/05/02. ^ Consult Maxwell's 'Electricity and Magnetism,1 Vol. II, Chap. xx 91. ^ Sejarah Energi Angin di Cutler J. Cleveland, (ed) Encyclopedia of ^ James Clerk Maxwell, On Physical Lines of Force , Philosophical Energy Vol.6, Elsevier, ISBN 978-1-60119-433-6, 2007, hlm. 421-422 Magazine, 1861 92. ^ See electrical units , electrical terms . ^ JJ O'Connor and EF Robertson, James Clerk Maxwell 93. ^ Miller 1981, Ch. 1 (http://translate.googleusercontent.com/translate_c?hl=id&sl=en& 94. ^ Pais 1982, Ch. 6b u=http://www-groups.dcs.st-and.ac.uk/%7Ehistory/Biographies 95. ^ a b Janssen, 2007 /Maxwell.html&prev=/search%3Fq 96. ^ Galison 2002 %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26sa%3DG& 97. ^ Darrigol 2005 rurl=translate.google.co.id&usg=ALkJrhgFh8njJtXr198. ^ Katzir 2005 F6FZJwMjUuma4h9w) , School of Mathematics and Statistics, University 99. ^ Miller 1981, Ch. 1.7 & 1.14 of St Andrews, Scotland, November 1997 100. ^ Pais 1982, Ch. 6 & 8 ^ James Clerk Maxwell, A Dynamical Theory of the Electromagnetic 101. ^ On the reception of relativity theory around the world, and the Field , Philosophical Transactions of the Royal Society of London 155, different controversies it encountered, see the articles in Thomas F. 459-512 (1865). Glick, ed., The Comparative Reception of Relativity (Kluwer Academic ^ Maxwell's 'Electricity and Magnetism,' preface Publishers, 1987), ISBN 9027724989 . ^ See oscillating current , telegraphy , wireless . 102. ^ Pais, Abraham (1982), Subtle is the Lord. The Science and the Life of ^ Consult 'Proc. Am. Inst. El. Engrs.,' 1901 Albert Einstein , Oxford University Press, pp. 382–386, ISBN ^ See electron. 0-19-520438-7 ^ Crookes presented a lecture to the British Association for the 103. ^ "Wireless electricity could power consumer, industrial electronics" Advancement of Science , in Sheffield, on Friday, 22 August 1879 [1] (http://translate.googleusercontent.com/translate_c?hl=id&sl=en& (http://translate.googleusercontent.com/translate_c?hl=id&sl=en& u=http://web.mit.edu/newsoffice/2006/wireless.html& u=http://www.worldcatlibraries.org/wcpa/top3mset prev=/search%3Fq /5dcb9349d366f8ec.html&prev=/search%3Fq %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26 %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26sa%3DG& sa%3DG&rurl=translate.google.co.id&usg=ALkJrhiY7fOfU3rurl=translate.google.co.id& r1kBsCx_5B4ao0OQcNA) . MIT News. 2006-11-14 . http://web.mit.edu usg=ALkJrhgXI_zmGTJgUwoSVNj8h5oDN8oCtw) [2] /newsoffice/2006/wireless.html . (http://translate.googleusercontent.com/translate_c?hl=id&sl=en& 104. ^ "Goodbye wires…" (http://translate.googleusercontent.com u=http://www.tfcbooks.com/mall/more/315rm.htm&prev=/search%3Fq /translate_c?hl=id&sl=en&u=http://web.mit.edu/newsoffice

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Sejarah elektromagnetik - Wikipedia, ensiklopedia bebas /2007/wireless-0607.html&prev=/search%3Fq %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26 sa%3DG&rurl=translate.google.co.id& usg=ALkJrhjjRgln4HT1SHvQWpVUziTIozUzNQ) . MIT News. 2007-06-07 . http://web.mit.edu/newsoffice/2007/wireless-0607.html . 105. ^ "Wireless Power Demonstrated" (http://translate.googleusercontent.com/translate_c?hl=id&sl=en&

file:///C:/Documents%20and%20Settings/it/My%20D... u=http://thefutureofthings.com/pod/250/wireless-powerdemonstrated.html&prev=/search%3Fq %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26 sa%3DG&rurl=translate.google.co.id& usg=ALkJrhj3bBPMLdMmAkXJQaqIq2YW1_GQeA) . http://thefutureofthings.com/pod/250/wireless-powerdemonstrated.html . Diperoleh 2008/12/09.

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Bakewell, FC (1853). Electric science; its history, phenomena, The Encyclopedia Americana; a library of universal knowledge and applications (http://translate.googleusercontent.com (http://translate.googleusercontent.com/translate_c?hl=id& /translate_c?hl=id&sl=en&u=http://books.google.com sl=en&u=http://books.google.com /books%3Fid%3DLks1AAAAMAAJ&prev=/search%3Fq /books%3Fid%3D62UMAAAAYAAJ&prev=/search%3Fq %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26sa%3DG& %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26s rurl=translate.google.co.id& rurl=translate.google.co.id& usg=ALkJrhhyv30BYErCiOmdwwBtBG3vhOVfYQ) . London: usg=ALkJrhhXFbm7SQdIoeDhU47DmUH9Gq19zQ) ; " Electricity, Ingram, Cooke. it's history and Progress ". (1918). New York: Encyclopedia Benjamin, P. (1898). Sebuah sejarah listrik (kenaikan Americana Corp. Page 171 intelektual listrik) dari kuno ke hari Benjamin Franklin. (http://translate.googleusercontent.com/translate_c?hl=id& (http://translate.googleusercontent.com/translate_c?hl=id& sl=en&u=http://books.google.com sl=en&u=http://books.google.com /books%3Fid%3D62UMAAAAYAAJ%26pg%3DPA171%26lr /books%3Fid%3DVLsKAAAAIAAJ&prev=/search%3Fq %3D%26as_brr%3D1&prev=/search%3Fq %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26sa%3DG& %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26s rurl=translate.google.co.id& rurl=translate.google.co.id& usg=ALkJrhhcA2ljLykZpG9Wj4eRLKtjAwNisw) New York: J. usg=ALkJrhgx5yeLVRBFJm7mQPnXNJEGm-Zq8Q#PPA171,M1) Wiley & Sons. Galison, Peter (2003), Einstein's Clocks, Poincaré's Maps: Darrigol, Olivier (2005), "The Genesis of the theory of relativity" Empires of Time , New York: WW Norton, ISBN 0393326047 (http://translate.googleusercontent.com/translate_c?hl=id& Gibson, CR (1907). Electricity of to-day, its work & mysteries sl=en&u=http://www.bourbaphy.fr/darrigol2.pdf& described in non-technical language prev=/search%3Fq (http://translate.googleusercontent.com/translate_c?hl=id& %3D%2522History%2Bof%2Belectromagnetism%2522%26hl% sl=en&u=http://books.google.com 3Did%26sa%3DG&rurl=translate.google.co.id& /books%3Fid%3DlwpVAAAAMAAJ&prev=/search%3Fq usg=ALkJrhhd1DRUzVnoHzGVto6ER_wPfKfcnw) (PDF), %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26s Séminaire Poincaré 1 : 1–22 , http://www.bourbaphy.fr rurl=translate.google.co.id& /darrigol2.pdf , retrieved 2009-06-21 usg=ALkJrhjoOEpk1rziy1thSdRTOof2z2fygg) . London: Seeley Durgin, WA (1912). Electricity, its history and development and co., limited (http://translate.googleusercontent.com/translate_c?hl=id& Heaviside, O. (1894). Electromagnetic theory sl=en&u=http://books.google.com (http://translate.googleusercontent.com/translate_c?hl=id& /books%3Fid%3DhQtJAAAAIAAJ&prev=/search%3Fq sl=en&u=http://books.google.com %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26sa%3DG& /books%3Fid%3D9ukEAAAAYAAJ&prev=/search%3Fq rurl=translate.google.co.id& %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26s usg=ALkJrhhy9TQ3EFnXAPQKiM7m9N5lZNq1eQ) . Chicago: AC rurl=translate.google.co.id& McClurg. usg=ALkJrhjBqT9RoLL0v7T1DdHQ4L1tIgDpxA) . London: "The Einstein, Albert, " Aether and the theory of relativity Electrician" Print. and Pub. (http://translate.googleusercontent.com/translate_c?hl=id& Ireland commissioners of nat. educ., (1861). 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May 5, 1920, in the University of Leyden ; classes general Janssen, Michel & Mecklenburg, Matthew (2007), From classical relativity as a form of (nonparticulate) aether theory) to relativistic mechanics: Electromagnetic models of the electron Einstein, Albert, The Investigation of the State of Aether in (http://translate.googleusercontent.com/translate_c?hl=id& Magnetic Fields (http://translate.googleusercontent.com sl=en&u=http://www.tc.umn.edu/%7Ejanss011/&prev= /translate_c?hl=id&sl=en&u=http://www.worldscibooks.com /search%3Fq /phy_etextbook/4454/4454_chap1.pdf&prev=/search%3Fq %3D%2522History%2Bof%2Belectromagnetism%2522%26hl% %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26sa%3DG& 3Did%26sa%3DG&rurl=translate.google.co.id& rurl=translate.google.co.id&usg=ALkJrhgttusg=ALkJrhgGP4dFrzzbqG2FDQUVanJ76TXeWQ) , in VF mlZEvT5qSCCwa8Ri0h0QXURg) , 1895. ( PDF format) Hendricks, et al., , Interactions: Mathematics, Physics and Einstein, Albert (1905a), "On a Heuristic Viewpoint Concerning Philosophy (Dordrecht: Springer): 65–134 , the Production and Transformation of Light", Annalen der Physik http://www.tc.umn.edu/~janss011/ 17 : 132–148 . This annus mirabilis paper on the photoelectric Jeans, JH (1908). The mathematical theory of electricity and effect was received by Annalen der Physik March 18. magnetism (http://translate.googleusercontent.com Einstein, Albert (1905b), "On the Motion—Required by the /translate_c?hl=id&sl=en&u=http://books.google.com Molecular Kinetic Theory of Heat—of Small Particles Suspended /books%3Fid%3DjKYTAAAAYAAJ&prev=/search%3Fq in a Stationary Liquid", Annalen der Physik 17 : 549–560 . This %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26s annus mirabilis paper on Brownian motion was received May 11. rurl=translate.google.co.id& Einstein, Albert (1905c), "On the Electrodynamics of Moving usg=ALkJrhh4ZswLlFz2PlZ_Bcb4Pk5tVTqrUQ) . Cambridge: Bodies", Annalen der Physik 17 : 891–921 . This annus mirabilis University Press. paper on special relativity was received June 30. Katzir, Shaul (2005), "Poincaré's Relativistic Physics: Its Origins Einstein, Albert (1905d), "Does the Inertia of a Body Depend and Nature", Phys. Perspect. 7 : 268–292, doi : Upon Its Energy Content?", Annalen der Physik 18 : 639–641 . 10.1007/s00016-004-0234-y This annus mirabilis paper on mass-energy equivalence was (http://translate.googleusercontent.com/translate_c?hl=id& received September 27. sl=en&u=http://dx.doi.org/10.1007%252Fs00016-004-0234" Aether (http://translate.googleusercontent.com y&prev=/search%3Fq /translate_c?hl=id&sl=en&u=http://encyclopedia.jrank.org %3D%2522History%2Bof%2Belectromagnetism%2522%26hl% /ADA_AIZ/AETHER_or_ETHER_Gr_deli_p_proba.html& 3Did%26sa%3DG&rurl=translate.google.co.id& prev=/search%3Fq usg=ALkJrhgd5b0BE2ZsG3pBzNSGNVV83V3j4g) %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26sa%3DG& Lord Kelvin (Sir William Thomson), " On Vortex Atoms ". rurl=translate.google.co.id& Proceedings of the Royal Society of Edinburgh, Vol. VI, 1867, usg=ALkJrhg40waoZGBilv6Thoag7seuaSKC7A) ", Encyclopædia pp. 94–105. (ed., Reprinted in Phil. Mag. Vol. XXXIV, 1867, Britannica, Eleventh Edition (1910–1911). Volume Vol. 1, Page pp. 15–24.) 297. Kolbe, Bruno; Francis ed Legge, Joseph Skellon, tr., " An

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Introduction to Electricity piles, the telegraph, the telephone, magnets and every other (http://translate.googleusercontent.com/translate_c?hl=id& branch of electrical application sl=en&u=http://books.google.com (http://translate.googleusercontent.com/translate_c?hl=id& /books%3Fvid%3D0o90G64Z2FDIyKUsLs9%26id%3D150IAAAAIAAJ& sl=en&u=http://books.google.com prev=/search%3Fq /books%3Fid%3DEexMAAAAMAAJ&prev=/search%3Fq %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26sa%3DG& %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26s rurl=translate.google.co.id& rurl=translate.google.co.id& usg=ALkJrhj3m4xecNFunRRhZXbbRYD15YBXlQ) ". Kegan Paul, usg=ALkJrhjGwefVr1pfz94jzXNURkUWwzZDXQ) . Philadelphia: Trench, Trübner, 1908. The Gebbie Pub. Co., Limited. Lodge, Oliver, " Ether ", Encyclopædia Britannica , Thirteenth Steinmetz, CP, " Transient Electric Phenomena Edition (1926). (http://translate.googleusercontent.com/translate_c?hl=id& Lodge, Oliver, "The Ether of Space". ISBN 1-4021-8302-X sl=en&u=http://books.google.com (paperback) ISBN 1-4021-1766-3 (hardcover) /books%3Fid%3DPBsAAAAAMAAJ%26pg%3DRA1-PA40%26lr Lodge, Oliver, "Ether and Reality". ISBN 0-7661-7865-X %3D%26as_brr%3D1&prev=/search%3Fq Lyons, TA (1901). A treatise on electromagnetic phenomena, %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26s and on the compass and its deviations aboard ship rurl=translate.google.co.id& (http://translate.googleusercontent.com/translate_c?hl=id& usg=ALkJrhjk3bdtfR3fsMXa72GJX7utX8ywXA#PRA1-PA38,M1) ". sl=en&u=http://books.google.com Page 38 (http://translate.googleusercontent.com /books%3Fid%3DJXkpAAAAYAAJ&prev=/search%3Fq /translate_c?hl=id&sl=en&u=http://books.google.com %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26sa%3DG& /books%3Fid%3DPBsAAAAAMAAJ%26pg%3DRA1-PA40%26lr rurl=translate.google.co.id& %3D%26as_brr%3D1&prev=/search%3Fq usg=ALkJrhh6W_TKVIFxXMifD91j6kSTqoGLKQ) . Mathematical, %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26s theoretical, and practical. New York: J. Wiley & Sons. rurl=translate.google.co.id& Maxwell, James Clerk, " Ether ", Encyclopædia Britannica, Ninth usg=ALkJrhjk3bdtfR3fsMXa72GJX7utX8ywXA#PRA1-PA38,M1) . Edition (1875-89). (ed., contained in: General Electric Company. General Electric Maxwell, JC, & Thompson, JJ (1892). A treatise on electricity review. Schenectady: General Electric Co. and magnetism (http://translate.googleusercontent.com (http://translate.googleusercontent.com/translate_c?hl=id& /translate_c?hl=id&sl=en&u=http://books.google.com sl=en&u=http://books.google.com /books%3Fid%3DqdYcAAAAMAAJ&prev=/search%3Fq /books%3Fid%3DPBsAAAAAMAAJ&prev=/search%3Fq %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26sa%3DG& %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26s rurl=translate.google.co.id& rurl=translate.google.co.id& usg=ALkJrhhk_dbWLo0N0gQoz9wjukrnkKpRBw) . Clarendon usg=ALkJrhjpYJRkVy7CtXnoUMdvllYT4fTi3Q) .) Press series. Oxford: Clarendon. Thompson, SP (1891). The electromagnet, and electromagnetic Miller, Arthur I. (1981), Albert Einstein's special theory of mechanism (http://translate.googleusercontent.com relativity. Emergence (1905) and early interpretation /translate_c?hl=id&sl=en&u=http://books.google.com (1905–1911) , Reading: Addison–Wesley, ISBN 0-201-04679-2 /books%3Fid%3DCLmFTg_j0pwC&prev=/search%3Fq Pais, Abraham (1982), Subtle is the Lord: The Science and the %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26s Life of Albert Einstein , New York: Oxford University Press, ISBN rurl=translate.google.co.id&usg=ALkJrhgbgtRk7u1hMz0-19-520438-7 IR7zeb0fa0FwEsQ) . London: E. & FN Spon. Priestley, J., & Mynde, J. (1775). The history and present state Whittaker, ET, " A History of the Theories of Aether and of electricity, with original experiments Electricity, from the Age of Descartes to the Close of the (http://translate.googleusercontent.com/translate_c?hl=id& Nineteenth Century (http://translate.googleusercontent.com sl=en&u=http://books.google.com /translate_c?hl=id&sl=en&u=http://www.archive.org/details /books%3Fid%3DRkpkAAAAMAAJ&prev=/search%3Fq /historyoftheorie00whitrich&prev=/search%3Fq %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26sa%3DG& %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26s rurl=translate.google.co.id& rurl=translate.google.co.id& usg=ALkJrhi0OndcjXZJ9UZRK9lOYPguwtW2bw) . London: usg=ALkJrhjo5k8R5U9FVRYnTCM_dKPRZy8JkA) ". Dublin Printed for C. Bathurst, and T. Lowndes; J. Rivington, and J. University Press series. London: Longmans, Green and Co.; Johnson; S. Crowder [and 4 others in London]. Urbanitzky, A. v., & Wormell, R. (1886). Electricity in the Schaffner, Kenneth F. : Nineteenth-century aether theories, service of man: a popular and practical treatise on the Oxford: Pergamon Press, 1972. (contains several reprints of applications of electricity in modern life original papers of famous physicists) (http://translate.googleusercontent.com/translate_c?hl=id& Slingo, M., Brooker, A., Urbanitzky, A., Perry, J., & Dibner, B. sl=en&u=http://books.google.com (1895). The cyclopædia of electrical engineering: containing a /books%3Fid%3DrkgOAAAAYAAJ&prev=/search%3Fq history of the discovery and application of electricity with its %3D%2522History%2Bof%2Belectromagnetism%2522%26hl%3Did%26s practice and achievements from the earliest period to the rurl=translate.google.co.id& present time: the whole being a practical guide to artisans, usg=ALkJrhgutW62nMpESGrZcZ5LF3Hc38AgPw) . London: engineers and students interested in the practice and Cassell &. development of electricity, electric lighting, motors, thermoRetrieved from " http://en.wikipedia.org/wiki/History_of_electromagnetism " Categories : Electricity | History of science | History of technology | History of physics

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