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

• A. Amplifier
• B. Amplification
• C. Arc
• D. Armature

Answer: (A)

The ability to boost the size of a signal is provided by an amplifier. An amplifier is a device that takes a relatively small input signal and produces a larger output signal, increasing voltage, current, or power by drawing energy from an external power supply. It preserves the signal’s basic form while raising its magnitude, which is essential for driving loads like relays, sensors, or other circuits in railway electrical systems. The term amplification refers to the process of increasing the signal, not the device itself. An arc is an unintended electrical discharge, and an armature is a rotating component inside motors or generators, not a device for boosting signal strength.