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.