# Resistance and Potentiometers

Resistance causes a voltage drop between two points in an electrical circuit. Resistance can be calculated by the following equation: R= E/I

where R = resistance (ohms) , E = voltage and I = amps. This equation is known as "Ohms Law", and is necessary when calculating the amount of resistance needed in order to complete a circuit.

A potentiometer is a voltage divider which can be adjusted to change the amount of resistance in a circuitry as needed. The amount of resistance of a potentiometer depends upon the alloy of wire and physical size of the winding. The resistance of a film-type element (conductive plastic or hybrid) can be changed by altering the composition of the conductive plastic used.