Explain the formation of depletion layer and potential barrier in p-n junction.
Draw the circuit diagram of a half wave rectifier and explain its working.

Explanation

`(i)` The small region in the velocity of the junction which is depleted of free charge carriers and has only immobile ions is called depletion region. The accumulation of negative charges in the `p`-region and positive charge in the `n`-region sets up a potential difference across the junction. This acts as a barrier and is called barrier potential `V_(B)`.

Working
`(a)` During positive half cycle of input alternating voltage, the diode is forward biased and a current flows through the load resistor `R_(L)` and we get an ouput voltage.
`(b)` During other negative half cycle of the input alternating voltage, the diode is reverse biased and it does not conduct (under break down region).
Hence, `AC` voltage can be rectified in the pulsating and unidirectional voltage.