SATHEE: semiconductor-electronics--materials-devices-and-simple-circuits Question 25

Semiconductor Electronics Materials Devices And Simple Circuits

semiconductor-electronics--materials-devices-and-simple-circuits Question 25

Question: Q. 4. A zener diode is fabricated by heavily doping both $p$ and $n$ sides of the junction. Explain, why? Briefly explain the use of zener diode as a $d c$ voltage regulator with the help of a circuit diagram.

U] [Delhi II 2017]

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Solution:

Ans. Explanation of heavily doping of both $p$ and $n$ sides of Zener diode.

Circuit diagram of Zener diode as a dc voltage regulator.

Explanation of the use of Zener diode as a $d c$ voltage regulator.

By heavily doping both $p$ and $n$ sides of the junction, depletion region formed is very thin, i.e., $< 10^{- 6} m$ . Hence, electric field, across the junction is very high $(5 \times 10^{6} V / M)$ even for a small reverse bias voltage. This can lead to a ‘breakdown’ during reverse biasing.

If the input voltage increases/decreases, current through resister $R_{s}$ , and Zener diode, also increases/decreases. This increases/decreases the voltage drop across $R_{s}$ without any change in voltage across the Zener diode.

This is because, in the breakbown region, Zener voltage remains constant even though the current through the Zener diode changes.

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Semiconductor Electronics Materials Devices And Simple Circuits

semiconductor-electronics--materials-devices-and-simple-circuits Question 25

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Semiconductor Electronics Materials Devices And Simple Circuits

semiconductor-electronics--materials-devices-and-simple-circuits Question 25

Table of Contents

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

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