What is Ohm's law?

In physics, one area of study is electric circuits, and Ohm's law relates three key concepts of electric circuits: voltage, current, and resistance. These quantities have standard units of measurement and standard abbreviations when used in formulas:
  • Voltage (V) is measured in volts (V).
  • Current (I) is measured in amps (A).
  • Resistance (R) is measured in ohms ().
Expressed as a formula, Ohm's law can be written as V=IR. In words, the voltage is quantitatively equal to the product of the current times the resistance. This relationship holds true for fairly large ranges of voltage, current, and resistance.