What tool is commonly used to measure electric current in a circuit?

An ammeter is specifically designed to measure electric current in a circuit, providing the reading in amperes. When inserted in series within a circuit, it allows for an accurate measurement of the flow of electric charge. The fundamental purpose of an ammeter is to quantify how much current is flowing through a conductor at any given time, which is essential for testing and troubleshooting electrical systems.

While a multimeter can also measure current, it's a versatile tool capable of measuring voltage and resistance in addition to current. Thus, calling it the primary tool for measuring electric current may not strictly identify it as the most specialized option compared to an ammeter, which exclusively focuses on current measurements.

A voltmeter is suited for measuring voltage across two points in a circuit, indicating electrical potential difference, while a power meter measures the power consumption in watts, which is different from measuring current alone. Therefore, the ammeter stands out as the most appropriate tool specifically designated for current measurement.