Which device would you use to convert a low-current signal into a higher-current drive for a speaker?

Which device would you use to convert a low-current signal into a higher-current drive for a speaker?

• A. Antenna
• B. Amplifier
• C. Transistor
• D. Watt-hours

Answer: (C)

Pushing more current into a speaker from a small input signal relies on current gain. A transistor does this by acting as a current booster: a small current into the base controls a much larger current from the collector to the emitter. This lets the speaker draw the needed drive current while the input signal remains small. In other words, the transistor is the active device that converts a low-current signal into a higher-current drive to the speaker, which is exactly what you need for audio amplification. Antenna and watt-hours aren’t about current amplification or driving loads, and while an amplifier is the overall function, the specific device that provides the current boost is the transistor.

Pushing more current into a speaker from a small input signal relies on current gain. A transistor does this by acting as a current booster: a small current into the base controls a much larger current from the collector to the emitter. This lets the speaker draw the needed drive current while the input signal remains small. In other words, the transistor is the active device that converts a low-current signal into a higher-current drive to the speaker, which is exactly what you need for audio amplification. Antenna and watt-hours aren’t about current amplification or driving loads, and while an amplifier is the overall function, the specific device that provides the current boost is the transistor.