Electrical formulas

Overview

Essential electrical engineering formulas for DC and AC circuits.

Key Formulas

Ohm's Law

$V = IR$

Voltage, current, resistance relationship.

Power (DC)

$P = VI = I^2R = V^2/R$

Electrical power.

AC Power (single phase)

$P = VI\cos\phi$

Real power in AC circuits.

Three-Phase Power

$P = \sqrt{3} V_L I_L \cos\phi$

Three-phase real power.

Impedance

$Z = \sqrt{R^2 + (X_L - X_C)^2}$

AC circuit impedance.

Reactance (inductive)

$X_L = 2\pi f L$

Inductive reactance.

Reactance (capacitive)

$X_C = \frac{1}{2\pi f C}$

Capacitive reactance.

Variables

References

• Original Source