Which instrument is essential for measuring voltage in an electrical circuit?

The instrument that is essential for measuring voltage in an electrical circuit is the voltmeter. A voltmeter is specifically designed to measure the potential difference (voltage) between two points in a circuit. It functions by being connected in parallel with the component whose voltage you want to measure, allowing it to accurately determine how much voltage is present. This capability is crucial for troubleshooting electrical issues, ensuring that devices operate within their specified voltage ranges, and verifying that circuit designs meet their intended specifications.

Other devices, such as an ammeter, measure current and would not be suitable for measuring voltage directly. An ohmmeter is used to measure resistance, which is also not relevant to voltage measurements. A multimeter can measure voltage, current, and resistance, making it a versatile tool. However, when specifically referring to an instrument that exclusively measures voltage, the voltmeter is the correct choice.