An elementary book on electricity and magnetism and their applications (1919)
Jackson, Dugald C. (Dugald Caleb), 1865-1951, Jackson, John Price, b. 1868, Black, Newton Henry, b. 1874 · New York, The Macmillian Co · leaf 587
5 to 100ohms; some operators head-receivers, which have very shortmagnets, have about 600 ohms, while those used in radio signal-ing sometimes have 1000 ohms or even higher resistance.The telephone receiver is almost incredibly sensitive. Ken-nelly has reported that in his experiments a sound could… … Fig. 373. — Simple form of microphone. ice, and therefore the transmitters which are now generallyused are based on an entirely different principle. When twobits of carbon are permitted to lie loosely against each other,the electrical resistance of their contact is very much changedwhen changes…
Electricity · Magnetism
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