Name the device used to measure the electrical resistance of a circuit.

The device used to measure the electrical resistance of a circuit is the ohmmeter. This instrument is specifically designed to measure the resistance in ohms and is an essential tool for diagnosing electrical problems. By applying a small voltage through the component being tested, it can determine how much opposition the component presents to the flow of current.

In contrast, a voltmeter measures the potential difference (voltage) across two points in a circuit, and an ammeter measures the current flowing through a circuit. While a multimeter can perform several functions, including measuring voltage, current, and resistance, the ohmmeter is specialized for resistance measurements. This means that when the task is to determine resistance specifically, the ohmmeter is the most appropriate and accurate tool to use.