Electronics

The basic Voltage divider equation is very simple, but often there is a known source voltage and a desired output voltage, the values of R1 and R2 are what needs to be calculated.

Basic Voltage divider equation:

Vo = (Vs * R2)/(R1 + R2)

So the equations to calculate for R1, R2 or Vs (just to be thorough) are:

R1 = ((Vs * R2) / Vo) - R2
R2 = (V0 * R1) / (Vs - Vo)
Vs = (Vo * (R1 + R2)) / R2