Ohm's Law

Ohm's Law defines the relationships between (P) power, (E) voltage, (I) current, and (R) resistance. One ohm is the resistance value through which one volt will maintain a current of one ampere.

( I ) Current is what flows on a wire or conductor like water flowing down a river. Current flows from points of high voltage to points of low voltage on the surface of a conductor. Current is measured in (A) amperes or amps.

( E ) Voltage is the difference in electrical potential between two points in a circuit. It's the push or pressure behind current flow through a circuit, and is measured in (V) volts.

( R ) Resistance determines how much current will flow through a component. Resistors are used to control voltage and current levels. A very high resistance allows a small amount of current to flow. A very low resistance allows a large amount of current to flow. Resistance is measured in ohms.

( P ) Power is the amount of current times the voltage level at a given point measured in wattage or watts.

Ohm's Law: Calculators Before clicking for the answer, enter numbers into the equation you wish to use to calculate for Current, Power, Resistance, or Voltage. Calculate for Current (I) I = P / E Power Voltage Current Watts Volts Amps I = Square Root of (P / R) Power Resistance Current Watts Ohms Amps I = E / R Voltage Resistance Current Volts Ohms Amps Calculate for Power (P) P = I 2 x R Current Resistance Power Amps Ohms Watts P = E x I Voltage Current Power Volts Amps Watts P = E 2 / R Voltage Resistance Power Volts Ohms Watts Calculate for Resistance (R) R = P / I 2 Power Current Resistance Watts Amps Ohms R = E / I Voltage Current Resistance Volts Amps Ohms R = E 2 / P Voltage Power Resistance Volts Watts Ohms Calculate for Voltage (E) E = I x R Current Resistance Voltage Amps Ohms Volts E = P / I Power Current Voltage Watts Amps Volts E = Square Root of (P x R) Power Resistance Voltage Watts Ohms Volts