The Secret Life of the Video Recorder
The principle of magnetic recording was invented by a Danish telephone engineer called Valdemar Poulsen in 1899. He used an electromagnet to record the tiny electric currents from a telephone to magnetise a steel wire. This recreated tiny currents in the electromagnet when it was replayed. All tape and video recorders still work this way.
heating system washing
SERIES 2: car internal combustion engine quartz watch telephone radio set video recorder
SERIES 3: fax machine lift word processor electric light photocopier the office
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(C) 1988-1994 Tim Hunkin. All rights reserved.