Potential Dividers and Potentiometers

A potential divider a voltage and reduces it to another voltage.It does this using a series circuit in which the voltage across eachresistor is divided in the ratio of their resistances.

The total resistance in the circuit above issincethese resistances are in series. Then

Now applyto

The power dissipated byismaximum when

Apotentiometer has the same arrangement, with the difference that theresistances are continuously variable. One such is shown below.

By moving the point of contact A, the ratio x:y and R-1 : R-2 canbe changed continously. Equation (1) becomes