Electrical
Power ↔ Current
Calculate current for DC, single-phase and three-phase AC circuits
W
V
0–1 (typically 0.8–0.95)
Result
Current11,11 A
Voltage230 V
Power2300 W
Power factor0,9
How does it work?
DC: P = V × I. Power equals voltage times current.
Single-phase AC: P = V × I × PF, where PF is the power factor (0–1).
Three-phase AC (balanced): P = √3 × VLL × I × PF, where VLL is the line-to-line voltage (typically 400 V in Europe).
The power factor accounts for the phase angle between voltage and current. Resistive loads (heaters) have PF ≈ 1. Motors and transformers typically have PF 0.8–0.95.
Example
DC example: 12 V battery, 120 W charger.
→ Current: 120 / 12 = 10 A
Single-phase AC: 2300 W appliance, 230 V, PF = 0.95.
→ I = 2300 / (230 × 0.95) = 10.5 A
Three-phase AC: 11 kW motor, 400 V, PF = 0.85.
→ I = 11 000 / (√3 × 400 × 0.85) = 18.7 A
Assumptions
- •Three-phase calculation uses line-to-line voltage (400 V in Europe)
- •Balanced three-phase load assumed
- •Power factor assumed constant
- •Result is RMS current