What is ohm's law?

Ohm's law states that the voltage across a resistive element equals the current through it multiplied by its resistance:

V = I × R

where V is in volts, I in amperes, and R in ohms. It can be rearranged as I = V/R or R = V/I. The associated power relationship is P = V × I, which combines with Ohm's law to give P = I²R = V²/R. Ohm's law is the foundational tool for analyzing voltage, current, and power in resistive circuits.