By increasing the resistance of R_{1} or decreasing the resistance of R_{2}, the V_{out} will be increased.

Sometimes, R_{1} or R_{2} are replaced by thermistors or light-dependent resistors (LDR)

- Thermistors’s resistance normally decreases as temperature increases.
- LDR’s resistance decreases as light intensity falling on them increases.

**Potentiometer uses the potential divider principle to measure potential differences and e.m.f.**

The unknown potential difference OR e.m.f., V_{AB} is applied across point A and B, **with the point at higher potential connected to A.**

Then J is moved along XY until a point Z where **no current flows** through the galvanometer (the galvanometer shows no deflection). This is the **balance point where V _{AB} is equal to V_{XZ}. **Then L

_{XZ}is known as the

**balance length.**

$V_{AB} = V_{XZ}$

$V_{AB} = \frac{L_{XZ}}{L_{XY}} V_{XY}$

$\frac{V_{XZ}}{V_{XY}} = \frac{R_{XZ}}{R_{XY}}$