Schematic image of a 220-ohm resistor and an LED connected to a 7805 5-volt regulator. Regulator pins are numbered from left to right. One terminal of the resistor is connected to the regulator’s output pin (pin 3), and the LED’s anode is connected to the other terminal of the resistor. The LED’s cathode is attached to the regulator’s ground pin (pin 2). A 9-12V DC power source is connected to the regulator’s voltage in (pin 1) and ground (pin 2).