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HALF WAVE

RECTIFIER

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CERTIFICATE

This is to certify that this project report on "HALF WAVE

RECTIFIER" is a bonafide record of work done by Arundhathy

Krishna for the requirements of AISCCE Practical examination 2013-

14.

Internal External

Examiner

Examiner

Principal

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ACKNOWLEDGEMENTS

I would like to express my special thanks of gratitude to my teachers Ms. Divya, Ms. Sandhya, Ms.Sivakami as well as our principal Rev. Fr. Mathew Arekulam who gave me the golden opportunity to do this wonderful project, which also helped me in doing a lot of Research.

Secondly I would also like to thank my parents and friends who helped me a lot in finishing this project within the limited time.

Lastly, I thank almighty, my parents, brother, sisters and friends for their constant encouragement without which this project would not be possible.

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CONTENTS

INTRODUCTION

AIM

APPARATUS

MECHANISM

PROCEDURE

CIRCUIT DIAGRAM

OBSERVATION

CALCULATION

RESULT

PRECAUTIONS

SOURCES OF ERROR

BIBLIOGRAPHY

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INTRODUCTION

Rectification is the process of converting alternating current (AC), which

periodically reverses direction, to direct current (DC), which flows in only one

direction.

The Half wave rectifier is a circuit, which converts an ac voltage to dc voltage. It

has many uses, but are often found serving as components of DC power

supplies and high-voltage direct current power transmission systems. Rectification

may serve in roles other than to generate direct current for use as a source of

power.

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AIM

To construct a half wave rectifier using a diode and to calculate its ripple factor

with and without filtering.

APPARATUS

A diode, an electrolytic condenser 1000 µF, a condenser of 0.1 µF, a resistance

1000Ω, a step down transformer with 220V - 240V primary and 6.3V, 100mA

secondary, ac and dc voltmeters or a millimeter, etc..

MECHANISM

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During the positive half cycle of the input voltage the polarity of the voltage across

the secondary forward biases the diode. As a result a current IL flows through the

load resistor, RL. The forward biased diode offers a very low resistance and hence

the voltage drop across it is very small. Thus the voltage appearing across the load

is practically the same as the input voltage at every instant.

During the negative half cycle of the input voltage the polarity of the secondary

voltage gets reversed. As a result, the diode is reverse biased. Practically no

current flows through the circuit and almost no voltage is developed across the

resistor. All input voltage appears across the diode itself.

 Hence we conclude that when the input voltage is going through its positive half

cycle, output voltage is almost the same as the input voltage and during the

negative half cycle no voltage is available across the load. This explains the

unidirectional pulsating dc waveform obtained as output. The process of removing

one half the input signal to establish a dc level is aptly called half wave

rectification.

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PROCEDURE

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Connections are made as shown in the circuit diagram. D is a diode. C is a 1000

µF elctrolytic condenser. C'' is a 0.1 µF condenser. RL is a 1KΩ resistor. The

rectified output is obtained across RL.

To find the ripple factor (r) with filter circuit

The ac output voltage Vac is measured by an ac voltmeter or by a millimeter. The

dc output voltage is also measured. The ripple factor is calculated by the equation

r = Vac/ Vdc

To find the ripple factor without filter circuit

The filter circuit is removed by disconnecting condenser C. The ripple

factor is determined as explained above.

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OBSERVATIONS

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(1) Rectifier with filter circuit

Vdc Vac

15.1 3V

(2) Rectifier without filter circuit

Vdc Vac

9.8V 9V

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CALCULATIONS

(1) To find ripple factor (r) of rectifier with filter circuit

AC output voltage( Vac) = 3V

DC output voltage(Vdc) = 15.1V

Ripple factor (r) = Vac/Vdc

= 3/15.1

= 0.19

(2) To find the ripple factor (r) without filter circuit

AC output voltage( Vac) = 9V

DC output voltage(Vdc) = 9.8V

Ripple factor (r) = Vac/Vdc

= 9/9.8

= 0.91

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RESULT

The ripple factor of the half wave rectifier

(a) With filter circuit = 0.19

(b) Without filter circuit = 0.91

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PRECAUTIONS

While doing the experiment do not exceed the ratings of the diode. This may lead to damage of the diode.

Connect the circuit components properly as shown in the circuit diagram.

Do not switch ON the power supply unless you have checked the circuit components a s per the cicuit diagram.

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SOURCES OF ERROR

The temperature coefficient of the components will change the longer the circuit is energized.

Temperature and humidity can affect the functioning of circuit.

Human error while taking the readings should be taken into consideration.

Error can occur in the resolution of equipments used.

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BIBLIOGRAPHY

Reference Data for Radio Engineers

Visionics

ebooks.com

chestofbooks.com

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