Ohm's Law defines the relationship between voltage (V), current (I), power (P) and resistance (R) in electrical circuits. It was discovered in 1827 by Georg Ohm (1789 – 1854), a German mathematician and physicist who, as a high school teacher, decided to study Alessandro Volta's new invention: the electromechanical cell (the precursor of the battery).
The relationships between the four important parameters of circuits are as follows:
  1. Voltage (V, in volts) calculations:
  2. Current (I, in amps) calculations:
  3. Power (P, in watts) calculations:
  4. Resistance (R, in Ω) calculations:
To use this calculator, enter a value for any two of the following: voltage, current, resistance, and power.
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Voltage:
Current:
Resistance:
Power:
  

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GlobalSpec, Inc. engineering calculators are free for individuals to use via this site under the terms and conditions set out under the Terms of Use of this web site and supplemented by this Engineering Calculator Disclaimer. These calculators are intended solely for general information and educational purposes, and are provided to help decrease the learning curve for those inexperienced in the engineering field and to give more experienced users additional reference tools.

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