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 R1 and R2, are purely resistive (Image 1).
Substituting R1 and R2 into the previous expression gives:
Given : Vin = 9V , Vout = 3V
If R1 = R2 then
If Vout = 6V and Vin = 9V (these are widely used voltages), so:
and from above value of R2 must be twice value of R1.
Here, both the resistors are unknown. So we have to assume one resistor R1/R2, keeping above ration in mind.
Let R2 = 10 KΩ
To solve for R1 (if R2 is assumed ):
By using : Vout = 3V , Vin = 9V and R2 = 10 KΩ in above equation
We get R1 = 5 KΩ
To solve for R2 (if R1 is assumed):
NOTE: This Vout/Vin ratio being >1 is not possible. By using these resistors alone it is not possible to either increase Vout above Vin or invert the voltage.