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CLASS: XII
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C E RTI FICATE

This is to certify that

Student
has successfully completed her Physics project
titled
HALF WA VE REC TIFIER

under the supervision and guidance of

PHYSICs TEACHER

in the partial fulfillment of the Biology

practice/
assessment conducted during the
academic year
2023-2024

EXAM I N E R T EAC H E R

Downloaded from: https://www.knowIedgecycIe.in

 ACKNOWLEDGEMENT

I would like to express my immense gratitude to

my physics teacher TEACHER NAME for the
help and guidance, he provided for completing this
project.

I also thank my parents who gave their ideas and

inputs in making this project. Most of all I thank
our school management, for providing us the
facilities and opportunity to do this project.

Lastly, I would like to thanks my classmates who

have done this project along with me. Their
support made this project fruitful.

3
 INDEX

CONTENT PAGE NO.

Topic 5

Introduction 6

Theory 7-9

Experiment 10

Procedure 11

Graph 12

Observation & Calculation 13

Result and Conclusion 14

Application , Advantages & 15-16

Disadvantages
Precautions 17

Bibliography 18

4
 TOPIC

Half wave Rectifier

5
 INTRODUCTION

 A rectifier a simple diode or group of diodes which

converts the Alternating Current (AC) into Direct
Current (DC).

 We know that a diode allows electric current in one

direction and blocks electric current in another direction.
We are using this principle to construct various types of
rectifiers.

 Rectifiers are classified into different types based on the

number of diodes used in the circuit or arrangement of
diodes in the circuit. The basic types of rectifiers are: half
wave rectifier and full wave rectifier.

 A half wave rectifier is a type of rectifier which converts

the positive half cycle (Positive current) of the input signal
into pulsating DC (Direct Current) output signal. The half
wave rectifier is the simplest form of the rectifier. We use
only a single diode to construct the half wave rectifier.

 The half wave rectifier is made up of an AC source,

transformer (step-down), diode, and resistor (load). The
diode is placed between the transformer and resistor (load).

6
 THEORY

The half-wave rectifier circuit is made by using a

semiconductor diode (D) with a load resistance RL .The
diode is connected in series with the secondary of the
transformer
and the load resistance RL .The primary of the transformer is
being connected to the ac supply mains.

The ac voltage across the secondary winding changes

polarities after every half cycle of input wave. During the
positive half-cycles of the input ac voltage i.e. when upper
end of the secondary winding is positive with respect to its
lower end, the diode is forward biased and therefore conducts
current. If the forward resistance of the diode is assumed to
be zero (in practice, however, a small resistance exists) the
input voltage during the positive half-cycles is directly
applied to
the load resistance RL. making its upper end positive with
respect to its lower end. The waveforms of the output current
and output voltage are of the same shape as that of the input
ac voltage.

During the negative half cycles of the input ac voltage i.e.

when the lower end of the secondary winding is positive
with respect to its upper end, the diode is reverse biased and
so does not conduct. Thus, during the negative half cycles of
the input ac voltage, the current through and voltage across
the load remains zero. The reverse current, being very small
7
 in

8
 magnitude, is neglected. Thus, for the negative half cycles no
power is delivered to the load.

Thus, the output voltage (VL) developed across load

resistance R is a series of positive half cycles of alternating
voltage, with intervening very small constant negative
voltage levels, It is obvious from the figure that the output is
not a steady dc, but only a pulsating dc wave. To make the
output wave smooth and useful in a DC power supply, we
have to use a filter across the load. Since only half-cycles of
the input wave are used, it is called a half wave rectifier.

Rectified output Voltage/Current

Waveform

Half-Wave Rectifier

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 Output of half wave rectifier is not a constant DC voltage. In
real life applications, we need a power supply with smooth
wave forms. In other words, we desire a DC power supply
with constant output voltage. A constant output voltage from
the DC power supply is very important as it directly impacts
the reliability of the electronic device we connect to the power
supply.

We can make the output of half wave rectifier smooth by

using a filter (a capacitor filter or an inductor filter) across
the diode. In some case resistor-capacitor coupled filter
(RC) is also used.

CIRCUIT DIAGRAM
22OV Input

10
 EXPERIMENT

MEASUREMENT OF CURRENT USING HALFWAVE

RECTFIER

AIM

To determine the current by measuring voltage and resistance using

Half wave Rectifier.

MATERIAL REQUIRED

 Diode
 Capacitor(50v)
 Voltmeter
 Resistance box
 Ac supply
 Wires for connection

11
 PROCEDURE

1. Take an AC Supply and connect it to switch.

11. Connect the terminal part of the AC to the p part of the

diode using wire.

111. Now Connect the other part of the AC terminal to the

Capacitor.

iv. Connect the n-part of the diode to the capacitor.

V. Connect the both ends of a capacitor to the resistance

box.

vi. Place a connection between voltmeter and resistance box

by joining the terminals of voltmeter.

V11. Now power on the switch and find out the resultant
voltage by changing the resistance box.

V111. Calculate the current by measuring the mean voltage and

resistance using ohm's law.

12
 GRAPH

13
 OBSERVATION

Resistance (in Ω ) Volt (in V)

1 0.7
2 1.1
3 1.4
4 1.6
5 1.8

CALCULATION

Vmean 0.7 + 1.1 + + 1.6 + 1.8

=

1.4 = 1.32 V
5
Rmean
1+ 2+ 3 4+ 5
=

+ = 3Ω
5

14
15
 RESULT

The average current produced by Half-wave

rectifier is
0.264 Ampere

CONCLUSION

A half wave rectifier is rarely used in practice. It is never

preferred as the power supply of an audio. circuit
because of the very high ripple factor. High ripple factor
will result in noises in input audio signal, which in turn
will affect audio quality.

Advantage of a half wave rectifier is only that its cheap,

simple and easy to construct. It is cheap because of the
low number of components involved. Simple because of
the straight forwardness in circuit design.

Measuring the mean current flow helps us to understand

the amount of AC current passed through the circuit.

16
 APPLICATION

In day-to-day life, the half-wave rectifier is mostly used in low

power applications because of its major disadvantage being the
output amplitude which is less than the input amplitude. Thus,
power is wasted and output is pulsated DC resulting in
excessive ripple.

Some of the uses and applications of rectifiers are in:

 Appliances

 Used with transformers

 Soldering

 AM radio

 Pulse generated circuits

 Single demodulation

 Voltage multiplier

17
 ADVANTAGES OF HALF WAVE RECTIFIER

 Simple circuit with a smaller number of components

 Economical at initial state. Although there is a higher

cost over time due to more power losses

DISADVANTAGES OF HALF WAVE RECTIFIER

 Converts only one cycle of the sinusoidal input given to

it and the other cycle gets wasted. Thus, giving more
power loss.

 HWR produces lower output voltage.

 The output current thus obtained is not purely DC and

it still contains a lot of ripple (i.e. it has a high ripple
factor)

18
 PRECAUTIONS

 Do not switch on the circuit before checking whether it is

correct or not

 The connection between voltmeter and resistance box

should be made correctly.

 Connect all the wires properly. Loose connection may

end up in failure of circuit.

 Capacitor of less volt may be connected to the diode.

 Diode should be connected in forward bias.

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 BIBLIOGRAPHY

 Wikipedia.com

 Google Search Engine

 Knowledgecycle.in/half-wave-rectifier-project

 dcaclab.com/blog/half-wave-rectifier

 www.electrical4u.com/half-wave-rectifiers

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