Electricity, history transistors

Modem electronic devices build on a long history of invention, discovery, and basic scientific research. The most critical devices are the control circuit elements — the diode and the switching devices. The latter began as triode vacuum tubes and are now generally transistors. Diodes pass current easily in only one direction. The original diode was invented in 1905 by J. Ambrose Flemming based on observations made in the laboratories of Edison Electric. This diode vacuum tube contained a hot filament, which emits electrons, and a metallic plate collector. Electrons flow only from filament to collector. The following year Lee DeForest created the triode vacuum tube and the electronic revolution was launched. 

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