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Solve for voltage, current, resistance, or power given any two known values.
Ohm's Law Equations:
V = I x R (Voltage = Current x Resistance)
I = V / R
R = V / I
P = V x I = I^2 x R = V^2 / R
Ohm's Law states that the current through a conductor is proportional to the voltage across it and inversely proportional to its resistance: V = IR.
Resistance is measured in ohms (symbol: omega). It was named after Georg Simon Ohm, who formulated the law in 1827.
Ohm's Law applies directly to DC circuits. For AC circuits, impedance (Z) replaces resistance and must account for inductive and capacitive reactance.
Electrical power (P) is the rate of energy transfer, measured in watts. P = V x I. A 120V circuit drawing 10A delivers 1,200W of power.
Ohm's Law requires exactly two known values to solve for the other two. Enter any two of the four fields (V, I, R, P) and select what you want to solve for.