What function can a multimeter serve to measure current flow in a circuit?

A multimeter can function as an ammeter, which is the correct choice in the context of measuring current flow in a circuit. When set to the ammeter mode, a multimeter allows you to measure the flow of electric current in amperes. To do this, the multimeter must be connected in series with the circuit, ensuring that all the current flows through the meter. This configuration is essential because ammeters are designed to measure current directly and need to be part of the circuit to provide an accurate reading.

In contrast, a voltmeter measures the voltage across two points in a circuit and is connected in parallel, not in series. An ohmmeter measures resistance in ohms and serves a different function by determining how much opposition exists in a circuit. A frequency counter measures the frequency of an alternating current (AC) signal, which also does not relate directly to measuring current flow in the same manner that an ammeter does. Understanding these functions highlights the unique capabilities of each measurement tool within electronic diagnostics and maintenance.