What is an ammeter?

• A. An instrument installed in series with a load used to measure voltage.
• B. An instrument used to measure weight changes.
• C. An instrument installed in series with an electrical load used to measure the amount of current flowing through the load.
• D. An instrument that displays time.

Answer: (C)

An ammeter is an instrument for measuring the current in an electrical circuit. To accurately measure how much current is flowing, it must be placed in series with the load so all the current passes through it. It’s designed with very low resistance to avoid significantly altering the circuit or the voltage across the load. It reads current in amperes. It isn’t used to measure voltage (that’s the job of a voltmeter connected in parallel), and it doesn’t measure weight or time.