AC power and power factor
Single-phase sinusoidal RMS power triangle and optional displacement-power-factor correction.
Development preview. Check the assumptions below before relying on a result. Calculations run in your browser.
How it calculates
Model: S=Vrms Irms; P=S cosφ; Q=S sinφ; Qc=P(tanφinitial−tanφtarget); C=Qc/(2πf Vrms²).
Assumptions
- Single-phase sinusoidal voltage and current only. Displacement PF is not true PF for distorted waveforms; harmonics, resonance, inrush and capacitor switching are outside this model.
- Capacitor result corrects a lagging load toward the target. Existing leading loads or already-better PF return zero added capacitance.
Worked example
These are the calculator's default inputs. Change any input above to recalculate.
Inputs
- Phase input
- power factor
- RMS voltage
- 230 V
- RMS current
- 5 A
- Displacement power factor
- 0.8
- Signed phase angle (+lagging)
- 36.8699 degree
- PF mode reactive sign
- lagging
- AC frequency
- 50 Hz
- Target lagging PF for capacitor sizing
- 0.95
Results
- Real power
- 920 W
- Reactive power (+inductive)
- 690 var
- Apparent power
- 1150 VA
- Displacement PF
- 0.8
- Current lag angle
- 36.8699 degree
- Required capacitive compensation
- 387.611 var
- Parallel correction capacitance
- 0.0000233233 F