Many electronic devices require an electrical supply at a specific voltage and they may suffer damage if the wrong voltage is supplied. The two most usual voltages in use are 5V and 3.3V. To ensure that your supply voltage is correct, you can use a voltage regulator and a battery of a higher voltage. The job of the voltage regulator is to maintain the correct voltage on the device side.
|1||Power in - usually a range such as 5-18V is allowed|