Step 5: Assembling the Board â Part 1 â Power
Take your LM7805 Voltage Regulator and place it somewhere at the top of your bread board similar to how it’s shown in the photo. When the regulator is facing you, the left pin is the input, the right pin is the output, and the center pin is the ground. Connect your 9 Volt battery connector to the input and ground. Then place a 10 uF capacitor between the input and ground and another between the output and ground.
Next place a 220 Ohm resistor plus the Red LED between the output and ground of the regulator. This is our power indication LED. Make sure the pin where the resistor and LED are connected is separate from any other pins we’ve used so far. The Resistor LED should be one path from the 5 volt output to ground and the short pin of the LED should be going to ground. Next you can connect the 5 volt output and ground to the rails on your breadboard. This will allow us to tap into the power and ground from the entire length of the breadboard.
That’s it for the 5 Volt power. For the 3.3 Volt power (if you chose to use it) simply follow the same guidelines as for the 5 volt power except for the following: It isn't shown on the schematics, but follows the same format, so you should be able to replicate it easily. THE PINS ARE DIFFERENT. Please review the datasheet for the pinout. The input to the 3.3 Volt Regulator will be the output of the 5 Volt regulator, you do not need an indication LED unless you would like one, and do not attach the output of the 3.3 volt regulator to the same rails the 5 volt regulator is attached to. I would just leave it in a small section on the other side of the breadboard for tapping into when needed.