## Finding a Resistance With a The Potential Divider

The potential divider is a device designed to limit the voltage across a pair of terminals for whatever reason. It does this by placing a resistor between the output terminals, in series with another resistor as shown in the diagram below. The input voltage is split in the ratio of the two resistances, so that the output voltage is given by Either or can be replaced by a variable voltage so that can be varied with a dial. If is replaced with a variable resistor of maximum resistance then can vary between and where for the latter, the variable resistance is set to zero.

If R-2 is replaced with a variable resistor of maximum resistance then can vary between 0 and and A potential divider can act as a safety device, because if there is a short circuit in the input circuit then the will limit the current and if there is a short circuit in the output circuit then will limit the resistance.

A potential divider can be used to measure a resistance Connect in in position of and measure then If and are known then can be calculated. 