What instrument is used to check voltage in a circuit?

A digital multimeter (DMM) is the appropriate instrument used to check voltage in a circuit. A DMM is versatile and can measure various electrical parameters, including voltage, current, and resistance, which makes it an essential tool for diagnosing electrical issues. When measuring voltage, a DMM provides a digital readout that is easy to interpret, allowing technicians to determine the voltage levels accurately within a circuit.

The other instruments listed serve different purposes. A test light is useful for indicating the presence of voltage but does not provide a specific voltage reading. An analog volt-ohmmeter can measure voltage but is generally less common than a DMM in modern applications due to its analog nature and potential for less precise readings. A battery load tester is specifically designed for testing the condition of batteries under load, rather than general voltage measurement in circuits.