Ohm's law

Ohm's law says that in an electrical circuit, the current passing through a resistor is related to the voltage difference and the electrical resistance between the two sides, as long as the physical conditions and the temperature of the conductor remain constant. Because there are three variables, it can be written in three ways, depending on which variable is placed on the left of the equals sign:

${\displaystyle I={\frac {V}{R}}\quad {\text{or}}\quad V=IR\quad {\text{or}}\quad R={\frac {V}{I}}}$.

Where I is the current in amperes, V is the potential difference in volts, and R is a constant, measured in ohms, called the resistance.