INDEX

Don't connect LED to Vcc. Suppose if you connect the output of 7805 directly to an LED then the voltage output of 7805 reduces to 3.85V from 5.02 voltage output of 7805( I checked it with a white LED producing green light). So when you connect LED to the output of any IC connect a series resistor with it. The brightness of LED is controlled by the series resistance. If you want a good brightness use R=100,150ohm. If you want a medium light series resistance=330ohm. The maximum value of 470ohm can be inserted for a small light.