A p-n junction when forward biased at 100 mV has a current of 50 `muA` and when reverse biased it has a constant current of 20 `muA` flowing through it
Calculate the magnitude of diffusion current when the diode is
(i) unbiased
(ii) forward biased at 100 mV
(iii) reverse biased at 100 mV

Explanation

(i) In unbiased p-n junction Diffusion current = Draft current = 20 `muA`
x b e the diffusion current
Then x- Drift current = Forward biasing current
`rArr d x- 20 mu A = 50 muA`
`rArr x= 70 mu A`
(ii) when p n junction is forward biased at 100 mv let x be the diffusion current
`rarr x=70 muA`
(iii) When p-n junction is reverse biased the diffusion current becomes negligible