Measurement of Electrical Power

Electric power in a circuit can be measured with an ammeter (amperemeter) and a voltmeter.

The power can be calculated as:

P = U × I or P = R × I²

Where:

• P = electric power (W, watts)
• U = voltage (V, volt)
• I = current (A, ampere)
• R = resistance (Ω, ohm)

Example

For a 230 V household circuit with an electric heater measuring 8 A:

P = (230 V) × (8 A) = 1,840 W