Thermionically emitted electrons can travel in beams, under side-electromagnet control, to fluorescent screens, where they excite phosphor crystals to make light {cathode ray tube}|. Cathode ray tubes are in TVs and oscilloscopes.
Circuit devices {detector} can select one signal from several.
Solid-state semiconductor circuit elements or vacuum tubes {diode}| can allow current to flow in only one direction. Diodes change alternating current to direct current. Tubes can have cathode emitter and anode plate. If plate is positive, emitted electrons flow toward plate. If plate is negative, no emitted electrons flow. For solid state, np junction allows charge to flow only in one direction, from P-type to N-type, with high resistance in other direction.
Circuit devices {mixer, signal} {electric circuit, mixer} can combine frequency signals.
Circuit devices {oscillator, circuit}| {electric oscillator} can change voltage waveform to other frequencies and amplitudes.
Devices {rectifier}| can change alternating to direct current.
Devices {rheostat}| can make variable resistance.
Circuit devices {wave shaper} can change voltage waveform.
Sunlight electric potential can make electric current in materials {photocell}|.
Shining light onto selenium {selenium cell} increases conductivity, because light increases electric field.
5-Physics-Electromagnetism-Circuit-Kinds
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Date Modified: 2022.0225