Which instrument measures electrical current?

Which instrument measures electrical current?

• A. Voltmeter
• B. Ammeter
• C. Ohmmeter
• D. Barometer

Answer: (B)

Measuring electrical current requires a device that senses the flow of charges as it passes through the circuit, so it must be placed in series with the circuit so all the current goes through it. An ammeter is designed for this purpose and is connected in series to read the current in amperes. In contrast, a voltmeter measures potential difference and is connected in parallel across a component to sense voltage, not current. An ohmmeter measures resistance by injecting a small test current and reading the resulting voltage (or vice versa), typically used when a circuit is de-energized. A barometer measures atmospheric pressure, not electrical current. So the instrument that measures current is the ammeter.

Measuring electrical current requires a device that senses the flow of charges as it passes through the circuit, so it must be placed in series with the circuit so all the current goes through it. An ammeter is designed for this purpose and is connected in series to read the current in amperes. In contrast, a voltmeter measures potential difference and is connected in parallel across a component to sense voltage, not current. An ohmmeter measures resistance by injecting a small test current and reading the resulting voltage (or vice versa), typically used when a circuit is de-energized. A barometer measures atmospheric pressure, not electrical current. So the instrument that measures current is the ammeter.