Tinkering Diary

 LED On/Off

Components:

1. Breadboard
2. 9V Battery
3. LED
4. Battery Cap
5. 220 ohm Resistor

Connections:

1. Connect the led to the breadboard (26 and 27)
2. Attach the battery cap to the 9V battery 
3. Connect the negative terminal of the battery to the negative terminal of the LED (27)
4. One terminal of the 220 ohm resistor to the positive terminal of the LED (26) and second terminal anywhere on the breadboard (10)
5. Connect the positive terminal of the 9V battery to the second terminal of the resistor (10)
6. The bulb glows.

Circuit Design:

Working Principle:

In the above circuit, when the current flow starts, the positive terminal of the battery is connected to the second terminal of the resistor. The resistor resists the high voltage, passing only a limited amount of current towards the LED. Resulting, the LED glows.