A galvanometer is a device used to measure what?

• A. Voltmeter for small voltages
• B. Ammeter for small currents
• C. Ohmmeter for resistance
• D. Wattmeter for power

Answer: (B)

A galvanometer is a very sensitive instrument that detects electric current by the magnetic deflection of a coil when current passes through it. The amount the needle deflects is proportional to the current, so its primary role is to measure small currents. In circuits, you’d place it in series to read how much current is flowing. It can be used as part of other instruments (with additional components) to measure voltage or resistance, but its fundamental function is to measure current. Voltmeter and ohmmeter measure voltage and resistance, respectively, and a wattmeter measures power by combining voltage and current readings.