St. Anselm’s Sr. Sec. School
Bhilwara, Rajasthan
Physics Project
Submitted By
:-
Aman Ajmera
Submitted To
:-
C.B.S.E.
Class
:-
XII-Science
Roll No.
:-
2
Scholar No.
:-
7287
Topic
:-
Zener Diode as a Voltage Regulator
CERTIFICATE
Name:
Aman Ajmera
Class:
XII-A
Roll No: 2
Institution: St. Anselm’s Sr. Sec. School, Bhilwara
This is certified to be the bona fide work of the student in the
“Physics” Laboratory during the academic year 2018-19.
Principal
Internal Examiner
External Examiner
Acknowledgement
I would like to express my special thanks of gratitude to my teacher
Mr. B.L. Heda Sir, our lab assistant Mr. Shankar Sir and Rev.
Father Principal Johnny Mathew who gave me the golden
opportunity to do this wonderful project on the topic Zener Diode
as a Voltage Regulator, which also helped me in doing a lot of
Research and I came to know about so many new things I am really
thankful to them.
Secondly I would also like to thank my parents and friends who
helped me a lot in finalizing this project within the limited time
frame.
INDEX
 Introduction- Semiconductor
 Zener Diode[Symbol and Characteristics]
 Zener Diode as a Voltage Regulator
Semiconductor: An Introduction
 Conductors: Allow Electric current to flow through them.
 Insulators: Do not allow Electric Current to flow through them.
 Semiconductors: Materials whose conductivity lies in between
Conductors and Semiconductors
What is Zener Diode?
A Zener diode is a heavily doped silicon crystal diode which allows
current to flow in the forward direction in the same manner as an
ideal diode. It also permits the current to flow in the reverse
direction when the voltage is above a certain value known as the
breakdown voltage. The layer at the junction of ‘P’ type and ‘N’ type.
When the applied voltage exceeds an specific amount Zener
breakdown takes place.
Symbol for Zener Diode-
Characteristics of a Zener Diode
When the diode is connected in forward bias diodeacts as a normal
diode. When the reverse bias voltage is greater than a
predetermined voltage then the Zener breakdown voltage occurs.
To get breakdown voltage sharp and distinct doping is controlled
and the surface imperfections are avoided. In the V-I
characteristics above Vz is the Zener voltage. And also the knee
voltage because at this point the current is the current is very
rapid.
Application of Zener Diode
Zener diode is popularly used as Shunt Regulator or Voltage
Regulator. As we have gone through the first part of the article we
know what is Zener diode and what is the basic principle of
operation. Here the question arises where this type of diodes can
be useful. Main application of this type of diodes are as voltage
regulator.Over voltage protector, as voltage reference.
Zener Diode as Voltage Regulator
The term regulator means which regulates. The Zener diode can
work as a voltage regulator if it is introduced in a circuit. The
output across the diode will be constant. It is driven by a current
source. As we know if the voltage across the diode exceeds a
certain value it would draw excessive current from the supply. The
basic diagram of Zener diode as voltage regulator is given below.