This voltage regulator was designed for one to connect the Fairy Light strings to the 12 volts of a dollhouse. It also provides a means to power individual LEDs by converting 12 volts down to 3 volts. This unit comes with three JST connectors to allow one to have three separate 3-volt circuits. The circuit board works with a 12-volt DC power supply only. I actually set the boards to 2.9 volts.