What device is commonly used to measure electrical voltage in a circuit?

A voltmeter is specifically designed for measuring electrical voltage in a circuit. It operates by connecting its probes across the two points in a circuit where the voltage is to be determined. The voltmeter provides a direct reading of voltage, typically displayed in volts, which is essential for troubleshooting and ensuring the proper functioning of electrical systems.

In contrast, a capacitance meter measures the capacitance of capacitors, which is not directly related to voltage. A frequency meter measures the frequency of electrical signals, often in oscillating circuits, while a clamp meter is primarily used to measure current flowing through a conductor without needing to make direct contact with the circuit. Each device serves its specific function, but the voltmeter is the correct choice when it comes to measuring voltage in a circuit.