A voltage divider is a circuit that produces an output voltage that is proportional to the input voltage. One typical configuration consists of a pair of resistors in series from the input voltage to ground, with the output voltage taken from the junction of the resistors. As an example: two equal-valued resistors will give an output voltage that is 50% of the input voltage.

Detailed explanation of a voltage divider.

Reoccurring questions

Once in a while a novice tries to use a voltage divider to lower a *supply* voltage. Here are some threads which explain why that's not a good idea: - http://electronics.stackexchange.com/questions/106718/when-would-i-use-a-voltage-regulator-vs-voltage-divider - http://electronics.stackexchange.com/questions/75448/how-to-reduce-dc-voltage-using-resistors