Potência AC

This calculator determines the active power in single-phase alternating current (AC) circuits. Active power is the portion of electrical power that actually performs work, such as heating, lighting, or turning motors. The calculation uses the formula P = V × I × cos φ, where V is the RMS voltage in volts, I is the RMS current in amperes, and cos φ is the power factor, representing the phase angle between voltage and current.

To use the tool, enter the voltage (V), current (I), and power factor (cos φ). The result is given in watts (W). Note that the power factor is a number between 0 and 1, usually indicated on equipment nameplates or measured with a network analyzer. In purely resistive systems, cos φ = 1, and active power equals apparent power (V × I).

This calculator is useful for sizing cables, circuit breakers, and transformers, as well as estimating the energy consumption of equipment such as motors, fluorescent lamps, and household appliances. Knowing the active power helps avoid overloads and optimize the power factor, reducing installation losses.

Caution: ensure that voltage and current values are RMS, not peak. The power factor must be correct for the equipment; typical values range from 0.6 to 0.9 for motors. This calculator does not apply to three-phase circuits without adaptation. If in doubt, consult an electrical engineer.