semiconductor-electronics--materials-devices-and-simple-circuits Question 35
Question: Q. 14. (i) Why is zener diode fabricated by heavily doping both $p$-and $n$-sides of the junction ?
(ii) Draw the circuit diagram of zener diode as a voltage regulator and briefly explain its working.
U] [Foreign 2014]
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Solution:
Ans. (i) Due to the heavy doping, the depletion layer becomes very thin and electric field, across the junction, becomes very high even for a small reverse bias voltage. (ii) Circuit diagram
Any increase / decrease in the input voltage results in increase / decrease of the voltage drop across $R_{L}$, without any change in the voltage across the Zener diode.
[CBSE Marking Scheme 2014] 1
Commonly Made Error
- Many students able to defined the working of zener diode but couldn’t write the reason of heavily doping of $p$ and $n$ sides of the junction.
