Find voltage and power from current and resistance.
Ohm's law states that the voltage across a resistor is directly proportional to the current flowing through it, with the resistance as the constant of proportionality: V = IR. It is one of the most fundamental relationships in electronics and lets you find any one of voltage, current, or resistance when the other two are known.
A resistor carrying current also dissipates electrical power as heat. The power can be written as P = VI, P = I²R, or P = V²/R. This calculator takes the current and resistance you supply, returns the voltage from V = IR, and the power from P = I²R.
No. It holds for ohmic materials such as metal resistors at constant temperature. Diodes, filaments, and semiconductors are non-ohmic, so their voltage and current are not linearly related.
Resistance is measured in ohms, symbol Ω, where one ohm is one volt per ampere.