In previous post we had gone through the formula and the circuit used as voltage divider using two resistors.

### Example Circuit :

A resistive divider is the case where both the resistors R_{1} and R_{2}, are purely resistive (Image 1).

Substituting R_{1} and R_{2} into the previous expression gives:

Given : Vin = 9V , Vout = 3V

If *R*_{1} = *R*_{2} then

If *V*_{out} = 6V and *V*_{in} = 9V (these are widely used voltages), so:

and from above value of *R*_{2} must be twice value of *R*_{1}.

Here, both the resistors are unknown. So we have to assume one resistor R_{1}/R_{2}, keeping above ration in mind.

Let R_{2} = 10 KΩ

To solve for R_{1} (if R_{2} is assumed ):

By using : *V*_{out} = 3V , *V*_{in} = 9V and R_{2} = 10 KΩ in above equation

We get R_{1} = 5 KΩ

Similarly,

To solve for R2 (if R_{1} is assumed):

NOTE: This *V*_{out}/*V*_{in} ratio being >1 is not possible. By using these resistors alone it is not possible to either increase *V*_{out} above *V*_{in} or invert the voltage.