Resistor Networks

SERIES

Rt = Total Resistance

Rt = R1 + R2 + R3

PARALLEL

Rt = Total Resistance 

Rt = [R1 x R2]/[R1 + R2]

PARALLEL (2 or more)

Rtotal (Rt) = 1/ [1/R1 + 1/R2 + 1/Rn]

VOLTAGE DIVIDER 

Vout = Vin x [ R1/(R1 + R2)]

R1 and R2 can be a potentiometer