Question

Why LED is kept in forward biased condition?

Hint:

Always connect LED in forward bias with a current-limiting resistor to avoid damage.

Answer 1

Step 1: Nature of LED.
LED (Light Emitting Diode) is a $p$-$n$ junction diode designed to emit photons when carriers recombine.
Step 2: Forward bias action.
When forward biased, electrons from the $n$-region and holes from the $p$-region recombine at the junction. This recombination releases energy in the form of light.
Step 3: Reverse bias case.
In reverse bias, the LED blocks current, and no recombination (hence no light) occurs.
Step 4: Conclusion.
Thus, LEDs must be kept forward biased for light emission.