What does a wattmeter measure?

A wattmeter measures electrical power in watts, which is a crucial aspect in electrical engineering. This device is specifically designed to quantify the rate at which electrical energy is consumed or produced in a circuit, providing valuable insight into the energy efficiency of electrical systems.

The primary operational principle of a wattmeter is based on the product of voltage (volts) and current (amperes), taking into account any phase difference between the current and voltage in an AC system. This allows it to deliver an accurate representation of true power, as opposed to merely measuring individual components like voltage or current.

Understanding this measure of power is vital for engineers as they assess the performance of electrical devices, calculate energy costs, and design efficient power systems. In contrast, devices that measure resistance, voltage, or current fulfill different roles and do not provide information about power consumption.