Instrument used to measure current in amperes directly in a circuit.

Instrument used to measure current in amperes directly in a circuit.

• A. Voltmeter
• B. Ammeter
• C. Galvanometer
• D. Multimeter

Answer: (B)

Measuring current directly in amperes is done with an ammeter. It is inserted in series with the circuit so every bit of current flows through it, and it is designed to have very low resistance to avoid dropping voltage or altering the circuit’s current. A voltmeter, by contrast, is connected in parallel and has high resistance to avoid drawing current, so it doesn’t measure current. A galvanometer is a sensitive detector for small currents and forms the basis of an ammeter, but on its own it isn’t suited for measuring large currents in amperes. A multimeter can measure current as well, but it’s a multi-function instrument and not the typical dedicated device used to measure current directly in a circuit.

Measuring current directly in amperes is done with an ammeter. It is inserted in series with the circuit so every bit of current flows through it, and it is designed to have very low resistance to avoid dropping voltage or altering the circuit’s current. A voltmeter, by contrast, is connected in parallel and has high resistance to avoid drawing current, so it doesn’t measure current. A galvanometer is a sensitive detector for small currents and forms the basis of an ammeter, but on its own it isn’t suited for measuring large currents in amperes. A multimeter can measure current as well, but it’s a multi-function instrument and not the typical dedicated device used to measure current directly in a circuit.