• LED which looks like a small bulb is a special kind of electronic component called diode. Full form of LED is light emitting diode.
• Diode is a semi conductor device which allows the current to pass through it in one direction only.
• If the diode is connected properly, that is, its positive terminal is connected to the positive supply, it allows the current to pass through it.
• LEDs are particular type of diode which convert electrical energy into light.

They glow up when current passes through it.

• LED is made up of gallium arsenide which converts electrical energy into light.
• LED requires very less power to light up as compared to electric bulb.
• LEDs being energy efficient have started being used widely in our day to day lives.
• They don’t heat up when current passes through them like normal electric bulbs.
• LED have two terminals. One terminal is slightly longer than the other.
• Longer leg is the positive terminal called ‘anode’ and the shorter leg is the negative terminal called ‘cathode’.