Ohm's Law

Ohm's law states that 1 volt can push 1 amp through 1 ohm of resistance. That being said, you can rewrite the equation several ways where if you know the resistance, and the amps running through it, you know the voltage applied. And if you know the amps and the volts you also know the resistance.

1volt can push 1 amp through one ohm, or .5amp through 2ohm, or .25amp through 4ohms. 4volts would be needed to push 1 amp through 4 ohms.

Where I is Current in Amps, V is Voltage in Volts and R is Resistance in Ohms, Ohm's Law is:

I = V&divide;R

It can also be written as:

V = I&times;R

R = V&divide;I