Ohm's Law

All substances have resistance to the flow of an electric direct current (DC). For example, metal

conductors such as copper have resistance in millions where as insulators have resistances in

mega-mega ohms (1 X 10¹²). Ohm's law states that the resistance of a substance is proportional

to the voltage drop of an applied current as it passes through a resistive substance, or

R = E/I

Where:

R = resistance (ohms)

E = applied voltage drop (volts)

I = current (amperes)