Which device measures the flow of electric current in a circuit?

The device that measures the flow of electric current in a circuit is known as an ammeter. The primary function of an ammeter is to determine the amount of current, measured in amperes (A), that is traveling through a particular point in an electrical circuit. It is connected in series with the circuit to measure the flow accurately, allowing users to observe and analyze the current's characteristics.

In contrast, an ohmmeter is designed to measure resistance in ohms and is used to diagnose the integrity of electrical components. A voltmeter, on the other hand, measures the voltage across two points in a circuit, indicating the potential difference. Lastly, a multimeter can perform multiple functions, including measuring voltage, current, and resistance, but when specifically seeking a device that primarily measures current, the ammeter is the correct choice.