Ohm's Law & Power

The basic relations between voltage, current, resistance and power in DC circuits or purely resistive AC circuits.

ElectricalOhmPower

Resistance R23Ω

METHOD

How it is calculated

V = I · R
P = V · I = I² · R = V² / R

ASSUMPTIONS & NOTES

Inductive/capacitive loads need impedance and power factor; use the motor current tool for motors.

Results are for preliminary design and checking; base the final design on the governing standard and safety factors.

RELATED TOOLS

Single/three-phase line: current, % voltage drop, cable loss and the smallest standard size within the limit.

Induction motor rated current, apparent and reactive power, and starting current for DOL and star-delta.

Capacitor rating (kVAr) and capacitance per phase needed to raise the power factor.

Preload and tightening torque for metric bolts, with a VDI 2230 equivalent-stress check.

Minimum solid shaft diameter under combined bending and torsion (ASME shaft code), with a standard size.

DIN 6885 key size, hub bearing-pressure and key shear checks, and the minimum key length.