ocr: ELECTRIC CABLE MICROPHONE BATTERY - - - AMPLIFIER SOUND SIGNAL. Often a signal is carried by an METAL CABLE electric current along a cable. A microphone converts a sound signal into a varying BOOSTER electric current. This can be L LE LE - AMPLIFIER used to modulate an otherwise constant voltage from a power SOUND ELECTRIC SIGNAL source, such as a battery. Amplifiers boost the signal, which can then travel to a loudspeaker that produces a copyoft the original sound. LOUDSPEAKER
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