# Ohm’s Law

Ohm’s Law is the mathematical relationship between the current, resistance and voltage in a circuit. Ohm’s law states that the voltage across a resistor is proportional to the current flowing through it. You can find below all three possible equations with Ohm’s Law:

$V=R*I$

$I=\cfrac{V}{R}$

$R=\cfrac{V}{I}$

V is the voltage across the resistor in volts, I is the current flowing through the resistor in amperes and R is the resistance of the resistor in ohms (Ω).

Units : V = Volts (V), I = Amperes (A) and R = Ohms (Ω)

Example : We want to calculate the current flowing into the resistor.

We need to use the second equation since we want to calculate the current and we have the value of the voltage across the resistor and the resistance of the resistor.

$I=\cfrac{V}{R}=\cfrac{12V}{50\Omega}=0.24A$