What instrument measures watts in electrical systems?

A watt meter is specifically designed to measure the electrical power in watts within a circuit. It directly quantifies the product of voltage and current while factoring in the phase difference, crucial for accurately assessing power in AC systems. This capability makes the watt meter ideal for determining how much electrical energy is being consumed or generated at any given moment.

In contrast, a voltmeter measures voltage, an ammeter measures current, and a power meter may have a broader application, potentially measuring other forms of power that are not strictly in watts or may not provide the same direct readings as a watt meter. Therefore, the watt meter is the appropriate instrument for the specific task of measuring watts in electrical systems.