Circuit Calculators
Professional electrical calculations at your fingertips
Ohm's Law Calculator
Calculate voltage, current, or resistance using V = IR
💡 Tip: Enter any 2 values, leave the 3rd empty to calculate it
V = I × R
Voltage = Current × Resistance
Power Calculator
Calculate electrical power using P = VI
💡 DC Circuit: P = V × I
P = V × I
功率 = 电压 × 电流
Voltage Drop Calculator
Calculate voltage drop in electrical cables
💡 Calculates voltage drop considering temperature and material
Formula: VD = (2 × ρ × I × L) / A
ρ adjusted for temperature: ρ(T) = ρ(20°C) × [1 + α × (T - 20)]
Acceptable: ≤ 5% voltage drop
Wire Size Calculator
Calculate recommended wire size based on current
💡 Validates both voltage drop and ampacity for safety
Standard sizes: 1.5, 2.5, 4, 6, 10, 16, 25, 35, 50, 70, 95, 120, 150, 185, 240 mm²
Ampacity based on IEC 60364-5-52 (Method C)
Three-Phase Calculator
Calculate three-phase power and current
💡 Calculates three-phase AC power (balanced load)
S = √3 × V × I (Apparent Power)
P = S × cos(φ) (Active Power)
Q = S × sin(φ) (Reactive Power)
calculators.transformer?.title
Transformer Calculator
Calculate transformer voltage ratio, turns ratio, and current ratio
Formula:
V₁/V₂ = N₁/N₂ = I₂/I₁
Voltage ratio = Turns ratio = Current inverse ratio
Primary Side
Secondary Side
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Motor Calculator
Calculate motor rated current and power requirements
Formula:
Three-phase: I = P / (√3 × V × η × PF)
Single-phase: I = P / (V × η × PF)
calculators.powerFactor?.title
Power Factor Calculator
Calculate power factor and recommend correction
Formula:
PF = P / S = cos(φ)
Q = √(S² - P²)
P is active power (kW), S is apparent power (kVA), Q is reactive power (kVAR)
💡 Ideal PF=1.0, industrial recommendation ≥0.95
💡 Low PF increases electricity cost and line losses
calculators.conduitFill?.title
Conduit Fill Calculator
Calculate conduit fill rate to ensure code compliance
💡 NEC code: 1 wire 53%, 2 wires 31%, ≥3 wires 40%
💡 Overfilling causes poor heat dissipation and difficult wire pulling
calculators.unitConverter?.title
Unit Converter
Quick conversion for common electrical units
💡 1 inch = 25.4 mm
💡 1 HP ≈ 745.7 W
💡 °F = °C × 9/5 + 32