What term describes a device used to increase the signal voltage, current or power?

• A. Autotransformer
• B. Amplitude
• C. Amplifier
• D. Arc

Answer: (C)

An amplifier is the device that increases the size of an electrical signal. It takes a small input signal and, with power from its own supply, produces a larger output signal. This boost can be in voltage, current, or overall power, and the amplifier aims to reproduce the input waveform with greater amplitude while staying within its linear operating range.

An autotransformer changes voltage levels through mutual inductance and redistribution of existing power rather than actively boosting a signal’s amplitude in the same sense as an amplifier. The term amplitude refers to the size of a signal, not a device, and an arc is a type of electrical discharge, not a signal-boosting component.