8.Wave shaping circuits (Half wave and full wave Rectifiers, Clippers PDF

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Summary

contains prelab, experiment data and post lab questions....

Description

DEPT. OF ELECTRICAL & ELECTRONICS ENGINEERING SRM INSTITUTE OF SCIENCE AND TECHNOLOGY, Kattankulathur – 603203.

Title of Experiment

: 8. Wave shaping circuits ( Half wave & Full Wave Rectifiers, Clippers)

Name of the candidate

: Vedant Kadam

Register Number

: RA2111003010241

Date of Experiment

: 20/11/2021

Date of submission

: 24/11/2021

Sl. No. 1

Marks Split up

Maximum marks (50) 5

Pre Lab questions

2

Preparation of observation

15

3

Execution of experiment

15

4

Calculation / Evaluation Result Post Lab questions

5

Total

of

Marks obtained

10 5 50

Staff Signature

PRE LAB QUESTIONS (Rectifiers) 1) What is the necessity of a rectifier? The primary application of the Rectifier is to derive DC power from AC power.They are used inside the power supplies of almost all electronic equipment.

2) What is PIV of a diode in Full Wave Rectifier (FWR) and Half Wave Rectifier (HWR)? The peak inverse voltage in case of a half wave rectifier is equivalent to the maximum value of applied input voltage. While peak inverse voltage of full wave rectifier is twice the maximum value of applied input voltage.

3) What is ripple factor? Why is it required? When the fluctuation occurs within the output of the rectifier then it is known as ripple. So this factor is essential to measure the rate of fluctuation within the resolved output. The ripple within output voltage can be reduced by using filters like capacitive or another kind of filter.

4) Why are filters connected at the output of rectifiers? To reduce the ripples at the output, we use filters. The filter is an electronic device that converts the pulsating Direct Current into pure Direct Current.

5) What are the types of filters used in rectifiers? And which is better and why? Types of filters: • Inductive Filter • Capacitor Filter • LC Filter • Pie Filter In order to reduce the AC component, we will be using different types of filters at the output side of the rectifier. So, these filters consist of Inductors and capacitor. 1. Inductor: It is connected in series in filter circuit because Inductors have inductive reactance which is an opposition to any changes and hence it offers high impedance to AC and low to DC because DC is a constant signal and AC will keep on varying with respect to time. 2. Capacitor: capacitor is connected in parallel in the filter circuit as the capacitor blocks DC and allows AC. So, any AC component in the output will pass through the capacitor to the ground and we get less amount of ac in the output.

Experiment No. 8 a) Date : 20/11/2021

SINGLE PHASE HALF WAVE RECTIFIER

Aim: To construct a half wave rectifier using diode and to draw its performance characteristics. Apparatus Required: S. No. 1

Components Required

Name

Range

Qty

Transformer

230/(6-0-6)V

1

S. No. 1 2

2

R.P.S

(0-30)V

2

3

Name

Range

Diode

IN4007

Resistor

1K Ω

1

-

1

Bread Board Capacitor

100µf

1

5

CRO

-

1

Without Filter Vrms

=

Vm / 2

(ii)

Vdc

=

Vm / ∏

(iii)

Ripple Factor =

√ ((Vrms / Vdc)2 – 1)

(iv)

Efficiency

(Vdc / Vrms)2 x 100

=

With Filter =

√ (Vrms2 + V dc2) (observe the circuit) 5.28-4.43=0.85V

(i)

Vrpp

(ii)

Vrms

=

Vrpp / (√3 x 2)

(iii)

Vdc

=

Vm – V rpp / 2

(iv)

Ripple Factor =

Vrms / Vdc

1

4

Formulae: (i)

Qty

Procedure: Without Filter 1. Give the connections as per the circuit diagram. 2. Give 230v, 50HZ I/P to the step down TFR where the secondary is connected to the Rectifier I/P. 3. Take the rectifier output across the Load. 4. Plot its performance graph.

With Filter 1. Give the connections as per the circuit diagram. 2. Give 230v, 50HZ I/P to the step down TFR where secondary connected to the Rectifier I/P. 3. Connect the Capacitor across the Load. 4. Take the rectifier output across the Load. 5. Plot its performance graph. Circuit Diagram

Tabular Column:

Without Filter : Vm

(V)

5.3

Vrms (V)

Vdc (V)

Ripple factor

Efficiency

2.65

1.68

1.219

40.18

With Filter : Vrpp

(V)

0.85

Model Graph

Vrms (V)

Vdc (V)

Ripple factor

0.245

4.86

0.05

Model Calculations:

E-Circuit:

Result: Successfully made the circuits,noted the readings and observations and plotted graphs on that basis. Understood half wave rectifier using diode (with or without capacitor) and drew its performance Characteristics.

Experiment No. 8 b) Date : 20/11/2021

SINGLE PHASE FULL WAVE RECTIFIER

Aim: To construct a single phase full-wave rectifier using diode and to draw its performance characteristics.

Apparatus Required: S. No. 1

Name Transformer

Components Required Range

Qty

230/(6-0-6)V

1

S. No. 1 2

2

R.P.S

(0-30)V

2

Formulae Without Filter (i)

Vrms

=

Vm / √2

(ii)

Vdc

=

2Vm / ∏

(iii)

Ripple Factor =

√ ((Vrms / Vdc)2 – 1)

(iv)

Efficiency

=

(Vdc / Vrms)2 x 100

With Filter (i)

Vrms

=

Vrpp /(2*√ 3)

(ii)

Vdc

=

Vm – V rpp

(iv)

Ripple Factor =

Vrms’/ Vdc

Name Diode

4

Resistor Bread Board Capacitor

5

CRO

6

Connecting wires

3

Range IN4007

Qt y 2

1K Ω

1

-

1

100µf 1Hz-20M Hz

1

-

1 Re q

Procedure: Without Filter 1.

Give the connections as per the circuit diagram.

2.

Give 230v, 50HZ I/P to the step down TFR where secondary connected to the Rectifier I/P.

3.

Take the rectifier output across the Load.

4.

Plot its performance graph.

With Filter 1. Give the connections as per the circuit diagram. 2. Give 230v, 50HZ I/P to the step down TFR where secondary connected to the Rectifier I/P. 3. Connect the Capacitor across the Load. 4. Take the rectifier output across the Load. 5. Plot its performance graph.

Circuit Diagram

Tabular Column: Without Filter Vm

Vrms

Vdc

Ripple factor

Efficiency

5.26

3.65

3.35

0.432

84.0

With Filter Vrms

Vrpp

Vdc

Ripple factor

0.115

0.40

4.84

0.023

Model Graph:

Model Calculations:

E-Circuit:

Result: Successfully constructed circuits, noted readings and understood Full Wave Rectifier using Diode (with or without capacitor) and drew its performance characteristics.

POST LAB QUESTIONS 1) What is the Transformer Utilization Factor (TUF)? The transformer utilization factor (TUF) of a rectifier circuit is defined as the ratio of the DC power available at the load resistor to the AC rating of the secondary coil of a transformer.

2) Mention the value of ripple factor for HWR, FWR & rectifier with centre tapped transformer. The value of ripple factor for HWR is 1.21, FWR is 0.48 & rectifier with center tapped transformer is 0.30.

3) What is the difference between an uncontrolled rectifier and a controlled rectifier? Which is advantageous and why? Uncontrolled Rectifiers provide a fixed DC output voltage for a given AC supply where diodes are used only. Controlled Rectifiers provide an adjustable DC output voltage by controlling the phase at which the devices are turned on, where thermistors and diodes are used. Controlled rectifier, because it compensates the DC line voltage variations caused by voltage variations on the medium voltage power network. To keep voltage constant even in case of load variations.

4) State the average and peak value of output voltage and current for full wave rectifier and half wave rectifier. Negative half cycles are absent in the output waveform of a half wave rectifier. So, in order to find the average value of the rectifier, the area under the positive half cycle is divided by the total base length. In a full wave rectifier, the negative polarity of the wave will be converted to positive polarity. So the average value can be found by taking the average of one positive half cycle.

5) What is PIV of a diode in half wave and full wave rectifier? Peak Inverse Voltage (PIV) is the maximum voltage that the diode can withstand during reverse bias conditions. If a voltage is applied more than the PIV, the diode will be destroyed.

Clippers PRE LAB QUESTIONS 1) What are the differences between linear and nonlinear wave shaping circuit? A Linear circuit is an electrical circuit and the parameters of this circuit such as Resistance, Capacitance, Inductance, etc. are always constant. Non-linear is also an electrical circuit, but the voltage and current change in this circuit change the parameters of the circuit such as waveforms, Resistance, Inductance, etc.

2) What are the applications of wave shaping circuit? The applications of wave shaping circuit are: • To hold the waveform to a particular DC level. • To generate one wave, form the other. • To limit the voltage level of the waveform of some presenting value and suppress all other voltage levels in excess of the present level.

3) What is wave shaping? A wave shaping circuit is the one which can be used to change the shape of a waveform from alternating current or direct current.

4) What is the necessity of wave shaping? • To hold the waveform to a particular DC level • To generate one waveform from another. • To limit the voltage level of the waveform to some preset value and suppress all other voltage levels in excess of the preset level. • To cut off positive and negative portions of input waveforms.

5) Mention the application of clipper and clamper. The application of clipper and clamper are: • They are frequently used for the separation of synchronizing signals from the composite picture signals. • The excessive noise spikes above a certain level can be limited or clipped in FM transmitters by using the series clippers.

Experiment No. 8c) Date : 20/11/2021

CLIPPERS

Aim: To study the clipping circuits for different reference voltages and to verify the responses. Apparatus Required: S.No.

Name

Components Required Range

Qty

1

CRO

1Hz-20MHz

1

2

RPS

(0–30) V

1

-

1

-

Req

Bread

3

Board Connectin

4

g Wires Function

5

Generator

1Hz-1MHz

S.No.

Name

Range

Qty

1

Resistor

10KΩ

1

2

Diode

IN4007

1

1

Theory The non-linear semiconductor diode in combination with resistor can function as a clipper circuit. Energy storage circuit components are not required in the basic process of clipping. These circuits will select part of an arbitrary waveform which lies above or below some particular reference voltage level and that selected part of the waveform is used for transmission. So they are referred to as voltage limiters, current limiters, amplitude selectors or slicers. There are three different types of clipping circuits. 1) Positive Clipping circuit. 2) Negative Clipping. 3) Positive and Negative Clipping (slicer).

In positive clipping circuit positive cycle of Sinusoidal signal is clipped and negative portion of sinusoidal signal is obtained in the output of reference voltage is added, instead of complete positive cycle that portion of the positive cycle which is above the reference voltage value is clipped. In the negative clipping circuit instead of positive portion of the sinusoidal signal, negative portion is clipped. In slicer both positive and negative portions of the sinusoidal signal are clipped.

Procedure: 1. Connect the circuit as shown in the circuit diagram. 2. Connect the function generator at the input terminals and CRO at the output terminals of the circuit. 3. Apply a sine wave signal of frequency 1 KHz, Amplitude greater than the reference voltage at the input and observe the output waveforms of the circuits.

Circuit Diagram Positive Clipper

Negative Clipper

Tabulation: Positive Clipper

Negative Clipper Unbiased Clipper

Vref = 0V

Vref = 0V

Output voltage

Time Period

Output voltage

Time Period

(V)

(ms)

(V)

(ms)

0.668

20

-0.688

20

Biased Clipper Vref =

2V

Vref =

2V

Output voltage

Time Period

Output voltage

Time Period

(V)

(ms)

(V)

(ms)

2.68

20

-2.68

20

E-Circuit:

Result: Successfully made circuits and studied the clipping circuits for different reference voltages and verified their responses.

POST LAB QUESTIONS

1) Differentiate +ve and -ve Clippers. The positive clipper which removes the positive half cycles of the input voltage. The negative clipper which removes the negative half cycles of the input voltage.

2) What is the function of Clampers? A clamper is an electronic circuit that fixes either the positive or the negative peak excursions of a signal to a defined value by shifting its DC value. The clamper does not restrict the peak-to-peak excursion of the signal; it moves the whole signal up or down so as to place the peaks at the reference level.

3) Write the classifications of clippers and clampers. Clippers can be broadly classified into two basic types of circuits. They are: series clippers and shunt or parallel clippers. Clampers can be broadly classified into two types. They are positive clampers and negative clampers.

4) Draw the output for the given input to the clamper circuit

5) What is the need of wave shaping circuit? The wave shaping is used to perform any one of the following functions: To hold the waveform to a particular DC level.To limit the voltage level of the waveform of some presenting value or suppressing all other voltage levels in excess of the present level.

VEDANT KADAM (RA 2111003010241)...