Voltage divider
From uCtrl.net
Information
A voltage divider is a linear circuit that produces an output voltage, a fraction of the input voltage. Very useful for making AVR microcontrollers measure a supply higher then 5V. Also used in power supplies as voltage regulator.
Vout = Vin*R2/(R1+R2)
Vin = (Vout*(R1+R2))/R2
