A potential divider circuit consists of two components
put in series across a voltage source.
They divide the voltage into smaller parts.
The formula for finding the output voltage is quite
simple. Because the current is the same
through both resistors, using Ohms Law, we can say:
Vout = Vin or Vout = Vin x Rbotto
Rbottom (Rtop + Rbottom) (Rtop + Rbottom)
You can
either remember the formula or use ratios for the calculations. Potential divider circuits can be used with
all kinds of sensors for the input to a system.
Example: In the circuit arrangement shown above, if Rtop is 100k and Rbottom is 50k and Vin is 9v, what is Vout? Since
Rtop is 2 x Rbottom, we have to split the 9v of Vin 2:1. 6v across Rtop and 3v across Rbottom works
out fine.
Or… Vout = 9v x 50k = 9x1/3 = 3v
(100k + 50k)
You can use
resistors, variable resistors, potentiometers, light dependent resistors (LDR),
thermistors, microphones, infra red sensors, touch sensors, water and moisture
sensors and switches of all kinds in a potential divider circuit. The potential divider circuit will form the
input for all sorts of processes and outputs.