Original: The mathematical equation that describes this relationship is : where V is the potential difference measured across the resistance in units of volts ; I is the current through the resistance in units of amperes and R is the resistance of the conductor in units of ohms .
Simplified: This relation is shown in the following formula : where I is the current in amperes , U is the potential difference in volts , and R is a constant , measured in ohms , called the resistance .