Use this electronics calculation for a first-pass component, converter, signal, motor, or sensor estimate when the stated operating conditions and units match the device data.

Resistance (ohm)

Required number input.

Impedance (ohm)

Required number input.

Calculate the power factor from resistance and impedance magnitude. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Power factor

The resulting power factor returned as a number.

• Compact electronics formulas omit some combination of tolerances, temperature drift, bandwidth, loading, parasitics, noise spectrum, nonlinearity, clipping, calibration, layout, and device-specific limits. Typical datasheet values are not guaranteed limits.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check the result against the current datasheet and worst-case operating corners, then verify the circuit or measurement with simulation and bench testing where failure matters.

• Ac Motor Reactive Power

  Calculate positive reactive-power magnitude for a balanced three-phase motor from line voltage, line current, and power factor.

• Motor Power Factor At Load

  Calculate balanced three-phase motor power factor as real input power divided by √3 times line voltage and line current; the result is a magnitude.

• Relay Coil Power

  Calculate DC relay-coil electrical power as applied voltage squared divided by coil resistance; AC impedance is outside this model.