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Power Electronics Lab ST2712

Operating Manual

Ver 1.1

An ISO 9001 : 2000 company

94-101, Electronic Complex Pardesipura, Indore- 452010, INDIA Tel : 91-731- 2570301/02, 4211100 Fax: 91- 731- 2555643 E-mail : [email protected] Website : www.scientech.bz Toll free No. : 1800-103-5050

www.hik-consulting.pl

mailto:[email protected]

http://www.scientech.bz

ST2712

Scientech Technologies Pvt. Ltd. 2


ST2712


Power Electronics Lab ST2712

Table of Contents

1. Safety Instructions 5

2. Introduction 6

3. Features 7

4. Technical Specifications 8 5. Functions of Various Blocks 9

6. Operating Instructions & Panel Control Description 10 7. Experiments

• Experiment 1 11 Study of the V-I Characteristics of SCR

• Experiment 2 13 Study of the V-I Characteristics of UJT

• Experiment 3 15 Study of the V-I Characteristics of MOSFET

• Experiment 4 17 Study of the V-I Characteristics of IGBT

• Experiment 5 19 Study of the V-I characteristics of DIAC

• Experiment 6 21 Study of the V-I Characteristics of TRIAC

• Experiment 7 23 Study of the V-I Characteristics of PUT

• Experiment 8 25 Study of the Class B Commutation Circuit

• Experiment 9 27 Study of the Class C Commutation Circuit

• Experiment 10 29 Study of the Class D Commutation Circuit

• Experiment 11 31 Study of the Class F Commutation Circuit

• Experiment 12 33 Study of R Triggering Circuit

• Experiment 13 35


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Study of RC (Half Wave) Triggering Circuit

• Experiment 14 37 Study of RC (Full Wave) Triggering Circuit

• Experiment 15 39 Study of the SCR Triggered by UJT

• Experiment 16 41 Study of the SCR Triggered by 555IC

• Experiment 17 43 Study of the SCR Triggered by Op-Amp 741IC

• Experiment 18 45 Study of the Ramp and Pedestal Triggering Circuit with Anti-

Parallel SCR in AC Load

• Experiment 19 46 Study of the UJT Relaxation Oscillator

• Experiment 20 50 Study of the Voltage Commutated Chopper

• Experiment 21 52 Study of the Bedford Inverter

• Experiment 22 54 Study of the Single Phase PWM Inverter using MOSFET and IGBT

• Experiment 23 56 Study of the Half Wave Controlled Rectifier with R and RL Load

• Experiment 24 61 Study of the Full Wave Controlled mid-point rectifier with R and RL

Load

• Experiment 25 65 Study of the Fully Controlled Bridge Rectifier with R and RL Load

8. Data Sheets 71

9. Warranty 85 10. List of Accessories 85

11. List of other Trainers available from us are 86


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Safety Instructions

Read the following safety instructions carefully before operating the instrument. To avoid any personal injury or damage to the instrument or any product connected to it.

Do not operate the instrument if suspect any damage within. The instrument should be serviced by qualified personnel only. For your safety : Use proper Mains cord : Use only the mains cord designed for this instrument.

Ensure that the mains cord is suitable for your country.

Ground the Instrument : This instrument is grounded through the protective earth conductor of the mains cord. To avoid electric shock the grounding conductor must be connected to the earth ground. Before making connections to the input terminals, ensure that the instrument is properly grounded.

Observe Terminal Ratings : To avoid fire or shock hazards, observe all ratings and marks on the instrument.

Use only the proper Fuse : Use the fuse type and rating specified for this instrument.

Use in proper Atmosphere : Please refer to operating conditions given in the manual.

1. Do not operate in wet / damp conditions. 2. Do not operate in an explosive atmosphere.


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RoHS Compliance

Scientech Products are RoHS Complied. RoHS Directive concerns with the restrictive use of Hazardous substances (Pb, Cd, Cr, Hg, Br compounds) in electric and electronic equipments. Scientech products are “Lead Free” and “Environment Friendly”. It is mandatory that service engineers use lead free solder wire and use the soldering irons upto (25 W) that reach a temperature of 450°C at the tip as the melting temperature of the unleaded solder is higher than the leaded solder.

Introduction

ST2712 Power Electronics Lab is useful Trainer to perform Power Electronics experiments. This trainer is very useful for student to know about the characteristics of power electronics devices and their applications.

This Trainer is equipped with following blocks for power electronics experiments

• DC supply.

• AC supply.

• Triggering circuit.

• Pulse amplifier with Isolation transformer.

• Separate Pulse transformer section.

• Single phase rectifier firing circuit.

• SCR assembly.

• Load section.

• Power Apparatus section.


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Features

• Self contained & easy to operate

• Functional blocks indicated on board mimic

• Solder less breadboard

• On board DC` power supply

• On board AC power supply

• Onboard pulse generator with PWM control, frequency control and duty cycle control

• On board single phase rectifier firing circuit with firing angle control

• On board power electronic devices

• On board pulse amplifier and isolation transformer section

• Load selection

• Rotary Switch provided to select the value of the load


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Technical Specifications

Size of Breadboard : 172.5 mm x 128.5mm DC Power Supply on board : +5 V, -5 V; 500 mA, +12V, -12 V; 500 mA +15 V; 250 mA +35V; -35V, 250 mA AC Power Supply on Board : 18V-0V-18V 0V-15V Triggering Circuit on Board : 5 gate signal output. Frequency range: 30Hz to 900Hz Variable. Amplitude: 12V. PWM control of G1, G2, G3 and G4 Duty cycle control of “Gate” Signal is 0 to 100%.

Single Phase Rectifier : Firing angle control 0 º-180 º variables. Firing Circuit on Board Four gate signal output with isolation SCR Assembly : 4 SCRs 2P4M, 600V, 2A Power Devices : IGBT G4BC20S, MOSFET IRF Z44N,

UJT 2N2646, DIAC DB3, TRIAC BT136, PUT 2N6027, SCR TYN616

Circuit Components on Board : Electrolytic Capacitor 10µF, 63V Electrolytic Capacitor 1µF, 63V

Met. Capacitor 0.33µF, 63V

Diode 1N4007,

Inductor 220µH, 4.7µH, 10mH Pulse transformer on Board : 2 nos. PT4502 1:1 and one is PT4503 1:1:1

Load selector : 6 load resistances- 47E/7W, 1K/1W, 1K/10W, 270E/5W, 120E/5W, 2K2 /2W Test points : 10 in numbers Weight : 5 Kgs. (approximately)

Dimensions (mm) : W420 x H100 x D255 Power requirement : 230V +/- 10%; 50 Hz.

Power consumption : 4VA (approximately)


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Functions of Various Blocks DC Power : This block provides fixed DC output of +5 V and -5 V, +12V and-12V, +15V, +35V and -35V.

AC Power : This block provides fixed AC output of 18V-0V-18V and 0V-15V.

Triggering Circuit : This block generates 4 gate pulses of frequency range 30Hz to 900Hz with PWM control and frequency control and 1 “Gate” signal with duty cycle control 0 to 100%. Single Phase Rectifier Firing Circuit : This block provides 4 gate and cathode signals with isolation for single phase controlled rectifiers. Firing angle control using Potentiometer from 0 to 180 degree.

Pulse amplifier and isolation transformer : This block provides amplification of gate signal and isolation between power circuit and triggering circuit. In which toggle switch for select 2 or 4 number of outputs with 2 different signals. When we select 4 signals then output is 4 signals with 2 signals are same but isolated.

SCR Assembly, Power Devices, Circuit Components : This block provides 4 SCRs, IGBT, MOSFET, PUT, UJT, DIAC, and TRIAC, 3 Diodes 1N4007, and Ele. Cap. 1µF/63V, MET. 0.1µF/63V and MET. Cap.0.33µF/63V. Inductors 68mH, 10mH.

Load section : This block provides different loads 1K/1W, 1K/10W, 120E/5W, 47E/7W, 2K2/2W, 270E/5W. This load is selected by selector switch.

Pulse transformer : This block provides pulse transformers for circuit isolation. In this block 2 transformers of 1:1 and one is 1:1:1.


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Operating Instructions and Panel Control Description The trainer is equipped with built in DC and AC power supply. When ‘On/Off’ switch of the trainer is turned ‘On’, the power LED indicates that trainer is ‘On’ and Various DC and AC supply are also ‘On’.

Frequency potentiometer of triggering circuit is used for varying the frequency of pulse signals G1, G2, G3, G4 and Gate. PWM potentiometer of triggering circuit is used to vary the pulse width for inverter circuit. Duty cycle control potentiometer for varying duty cycle of only “Gate” signal for speed control using MOSFET.

In the single phase rectifier firing circuit there are gate signals for two groups of rectifier devices. The firing angle is controlled using firing control potentiometer.

For Bedford inverter and series inverter, amplifier and isolation section is used. In which for series inverter select two outputs by switch and for Bedford inverter require four output signals. The load value of resistance given in manual and select by switch. Then ‘On’ the supply otherwise load value is burned see also inductor.

The experiments listed in this manual are only for guidance. The trainees are expected to apply their skills to modify or correct the circuits wherever required. Pin diagrams of devices are given in the end of this manual. Use them for proper connections.


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Experiment 1 Objective : To study and plot the V-I Characteristics of SCR Equipments Needed : Equipments Quantity 1. Resistance 470E, ¼ W 1

2. Resistance 2K2, 2W (on board) 1 3. SCR TYN 616 (on board) 1

4. Potentiometer 5K 2

Circuit diagram : Circuit used to plot characteristics of SCR is shown in figure 1.

V-I Characteristics Figure 1

Procedure :

• Make circuit connections as shown in the figure 1 using patch cords. 1. To plot the V -I characteristics proceed as follows.

2. Rotate both the potentiometer P1 and P2 in fully counter clockwise direction, connect voltmeter to point ‘6’ & ground to read VG and at point ‘3’ & ground to read VAK.

3. Connect ammeter at point ‘1’ & ‘2’ to indicate the current IA and at point ‘4’ & ‘5’ to indicate the gate current IG.

4. Switch on the power supply.

5. Vary potentiometer P2 to set the gate current IG to a lower value (5.6mA, 5.7mA, 5.8mA.).


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6. Increase anode voltage VA gradually by varying potentiometer P1. 7. Observe the current IA in the anode circuit, It shows almost zero current at the

initial stage 8. At certain point of positive anode voltage current IA shows sudden rise in

reading & voltmeter reading falls down to almost zero. This action indicates the firing of SCR.

9. If this not happens, repeat the procedure from step 5 for slightly higher value of gate current IG.

10. Try the various value of gate current to get the firing of SCR. 11. Keeping gate current constant observe precisely the firing voltage of SCR and

record it in the observation table. 12. Also record the anode voltage VA & anode current after firing of the SCR.

13. Plot the graph of VA versus IA.

Observation Table :

Anode current IA (mA) at constant value of Gate current S.

No.

Anode Voltage

VA IG = ____mA IG = ____mA IG = ____mA

1.

2. 3.

4. 5.

6. 7.

8. 9.

10.


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Experiment 2 Objective : Study of the Characteristic of UJT and Calculate Interbase Resistance and Intrinsic Standoff Ratio Equipments Needed : Equipments Quantity 1. Resistance 470E, 1/4W 2 2. Potentiometer 5K 2

3. UJT 2N2646 (on board) 1

Circuit diagram : Circuit used to plot characteristics of Unijunction transistor is shown in figure 2

Emitter Characteristics

Figure 2 Procedure :

• Make circuit as shown in the figure 2 using patch cords.

• To plot the emitter characteristics proceed as follows: 1. Rotate both the potentiometer P1 and P2 fully in counter clockwise direction. 2. Connect voltmeter between test point ‘6’ and ground to read VBB and other

between test point ‘3’ and ground to read VE. 3. Connect ammeter between point ‘1’ and ‘2’ to measure the emitter current IE

and at point ‘4’ and ‘5’ to measure the base current IB. 4. Switch on the power supply.

5. Vary potentiometer P2 and set a value of voltage VBB = 5 V. 6. Increase the emitter voltage VE in steps.

7. Keep increasing VE until it drops on voltmeter, UJT fires and emitter current flows rapidly.


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8. Record the corresponding Emitter current for each value of Emitter voltage VE in an observation table 1.

9. Repeat the above procedure from step 8 for VBB = 10 V and 15 V. 10. Plot the graph of VE versus IE with the help of observation table 1.

Observation Table :

Emitter current IE (mA) at constant value of output voltage S.

No.

Emitter voltage

VE VBB = 5V VBB = 10V VBB = 15V

1. 2. 3. 4. 5. 6. 7. 8. 9.

10. 11. 12. 13. 14. 15.

Calculations : 1. Interbase Resistance(Rss)

It is the sum of resistance between base 1 & base2.

RBB = RB1 + RB2 It ranges from 4 to 10 K ohms when Ie = 0.

2. Intrinsic Stand-off Ratio (η)

η = RB1 (RB1 + RB2) = RBB1 RBB It ranges from 0.51 to 0.82.


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Experiment 3 Objective : Study of the Characteristics of MOSFET Equipments Needed : Equipment Quantity 1. Resistance 750E, 1/4W 1

2. Resistance 1K, 1W 1 3. Resistance 470E, 1/4W 1

4. Zener diode 5V 1 5. Potentiometer 5K 2

6. MOSFET IRFZ44N (on board) 1

Circuit diagram : Circuit used to plot characteristics of MOSFET is shown in figure 3

Drain Characteristics Figure 3

Procedure :


• To plot drain characteristics proceed as follows:

1. Connect the circuit on the breadboard as shown in figure 2. Rotate both the potentiometer P1 and P2 fully in counter clockwise direction.

3. Connect point ‘1’ and ‘2’ and connect ammeter between point ‘4’ and ‘5’. 4. Connect one voltmeter between point ‘6’ and ground to measure drain voltage

VDS other voltmeter between point ‘3’ and ground to measure gate voltage VGS.

5. Switch ‘On’ the power supply.


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6. Vary potentiometer P2 and set a value of gate voltage VGS at some constant value (3 V, 3.1 V, 3.2 V)

7. Vary the potentiometer P1 so as to increase the value of drain voltage VDS from zero to 35 V in step and measure the corresponding values of drain current ID for different constant value gate voltage VGS in an observation table.

8. Rotate potentiometer P1 fully in counter clockwise direction.

9. Repeat the procedure from step 6 for different sets of gate voltage VGS. 10. Plot a curve between drain voltage VDS and drain current ID using suitable scale

with the help of observation table. This curve is the required drain characteristic.

Observation Table :

Drain current ID (mA) at constant value of gate voltage S.

No.

Drain voltage

VDS VGS = 3V VGS = 3.1V VGS = 3.2V

1. 2. 3. 4. 5. 6. 7. 8. 9.

10.


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Experiment 4 Objective : Study of the Characteristics of IGBT Equipments Needed : Equipment Quantity 1. Resistance 25E, 5W 1

2. Resistance 1K, 1/4W 1 3. Potentiometer 5K 2

4. IGBT G4BC20S (on board) 1

Circuit diagram : Circuit used to plot the characteristics of an IGBT is shown in figure 4.

IGBT Characteristics Figure 4

Procedure :

• Make circuit as shown in the figure 4 using patch cords. 1. Rotate the potentiometer P1 fully in clockwise direction and P2 fully in the

counter clockwise direction. 2. Connect Ammeter between point‘4’ and ‘5’ to measure collector current IC

(mA). 3. Connect point ‘1’ and ‘2’.

4. Connect voltmeter between point ‘3’ and ground to measure the Gate voltage VGE and between point ‘6’ and ground to measure collector voltage VCE.

5. Switch ‘On’ the power supply. 6. Vary the potentiometer P1 in counterclockwise direction to set the gate voltage

VGE (between 4.8V and 6.5V).


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7. Vary the potentiometer P2 in clockwise direction so as to increase the value of collector-emitter voltage VCE from 0 to 35V in step and measure the corresponding values of collector current IC for different constant value of gate voltage VGE in an Observation Table 1.

8. Rotate the potentiometer P2 fully in the CCW direction and potentiometer P1 fully in clock wise direction.

9. Repeat the procedure from step 6 for different sets of gate voltage VGE. 10. Plot a curve between collector-emitter voltage current (VCE) and Collector

current IC using suitable scale with the help of observation Table 1. This curve is the required collector characteristic.

Observation table :

Collector current IC (mA) at constant value of gate voltage VGE(volt) S. No.

Collector Voltage

VCE VGE = V VGE = V VGE = V

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

13.

14.

15.

16. www.hik-consulting.pl

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Experiment 5 Objective : Study of the Characteristics of DIAC and plot its V-I Characteristics Curve Equipments Needed : Equipment Quantity 1. Resistance 1K, 1W (on board) 1

2. DIAC DB3 (on board) 1 3. Potentiometer 5K 1

Circuit diagram : Circuit used to plot different characteristics of DIAC is shown in figure 5.


Procedure : 1. Make circuit as shown in the figure 5 using patch cords.

2. To plot V-I characteristics proceed as follows. 3. Rotate both the potentiometer P1 fully in counter clockwise direction.

4. Connect voltmeter across point ‘3’ & ground to read voltage VA. 5. Connect ammeter between point ‘1’ & ‘2’ to indicate the current IA.

6. Switch ‘On’ the power supply. 7. Put the +35 V switch ‘On’.

8. Vary the potentiometer P1 so as to increase the value of DIAC voltage VA and measure the corresponding values of current IA in an observation table 1.

9. Plot the curve between + VA and + IA


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10. Rotate potentiometer P1 fully in counter clockwise direction. 11. Switch ‘Off’ the power supply.

12. Put the switch towards -35 V. 13. Switch ‘On’ the power supply.

14. Vary the potentiometer P1 so as to increase the value of DIAC voltage VA and measure the corresponding values of current IA in an observation table.

15. Plot the curve between –VA and - IA. Observation Table :

Serial Number

Diac Voltage

Va

Diac Current

Ia

Diac Voltage

-Va

Diac Current

-Ia

1. 2. 3.

4. 5. 6.

7. 8. 9.

10.


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Experiment 6 Objective : Study of the V-I Characteristics of TRIAC Equipments Needed : Equipment Quantity 1. Resistance 470E, 1/4W 1

2. Resistance 2K2, 2W (on board) 1 3. TRIAC BT136 (on board) 1


Circuit diagram : Circuit used to plot different characteristics of TRIAC is shown in figure 6.


Procedure : 1. Make circuit as shown in the figure 6 using patch cords. 2. To plot the V-I characteristics proceed as follows: 3. Rotate both the potentiometer P1 and P2 fully in counter clockwise direction. 4. Connect voltmeter between point ‘6’ and ground to read VG and between point

‘3’ and ground to read VA. 5. Connect one ammeter between point ‘1’ & ‘2’ to indicate the current IA and

other between point ‘4’ & ‘5’ to indicates the gate current IG. 6. Switch on the power supply. 7. Put the switch towards +35 V. 8. Vary potentiometer P2 to set the gate current IG to a lower value. 9. Increase anode voltage VA gradually by varying potentiometer P1. 10. Observe the current la in the anode circuit, It shows almost zero current at the

initial stage.


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11. If this not happens, repeat the procedure from step 8 slight higher value of gate current IG.

12. Try the various value of gate current to get the firing of TRIAC. 13. Also record the anode voltage VA & anode current after firing of the TRIAC in

table 1. 14. Rotate potentiometer P1 fully in CCW direction. 15. Put the switch towards -35 V and repeat from step 6 and note down the reading

in observation table 2. 16. Plot the graph of -VA versus -IA.

Observation Table 1 :

Anode current Ia (mA) at constant value of Gate current (when switch is to words 35V) S.

No.

Anode voltage

Va Ig = __ mA Ig = __ mA Ig = __ mA 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.


Anode current Ia (mA) at constant value of Gate current (when switch is to words -35V) S.

No.

Anode voltage

Va Ig = __ mA Ig = __ mA Ig = __ mA 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.


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Experiment 7 Objective : Study of the Characteristics of PUT Equipments Needed : Equipment Quantity

1. Resistance 2K5, 1/4W 1

2. Resistance 10K, 1/4W 1 3. Resistance 2K2, 2W (on board) 1

4. PUT 2N 6027 (on board) 1 5. Potentiometer 5K 1


Circuit diagram : Circuit used to plot the characteristics of a PUT is shown in figure 7.


Procedure :


• To plot characteristics proceed as follows: 1. Rotate both the potentiometers P1 and P2 fully in the clockwise direction.

2. Connect Ammeter between point ‘4’ and ‘5’ to measure gate current IG (mA) and between point ‘1’ and ‘2’ to measure anode current IA (mA).

3. Connect voltmeter between point ‘3’ and ground to measure the anode voltage (VA).


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4. Connect voltmeter between point ‘6’ and ground to measure the Gate voltage VG.

5. Switch ‘On’ the power supply. 6. Vary the potentiometer P2 to set a value of gate voltage VG at some constant

value (2.0V, 5.0V, 10V).

7. Vary the potentiometer P1 so as to increase the value of anode voltage VA from 0 to 15V in step and measure the corresponding values of anode current IA for different constant value of gate voltage VG in an Observation Table 1.

8. Rotate the potentiometer P2 fully in the CCW direction. 9. Repeat the procedure from step 6 for different sets of gate voltage VG.

10. Plot a curve between anode voltage (VA) and anode current IA using suitable scale with the help of observation Table 1. This curve is required V-I characteristic.

Observation Table :

Anode voltage VA, anode current IA and gate current IG at different gate voltage

VG = 2.0V VG = 5.0V VG = 10.0V S.

No.

VA IA IG VA IA IG VA IA IG


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Experiment 8 Objective : Study of Class B Commutation Circuit Equipments Needed : Equipment Quantity 1. Resistance 1K, 1/4W 1

2. Electrolytic Capacitor 2.2µF/25V 1 3. Inductor 10mH (on board) 1

4. SCR 2P4M (on board) 1 Circuit diagram : The circuit diagram of class B commutation circuits as follows :

Class-B Commutation Circuit Figure 8

Procedure : 1. Connect circuit as shown above figure 8. 2. Connect Gate of SCR to G1 signal.

3. Switch on the power supply. 4. Connect oscilloscope across SCR and observe the waveform.

5. Connect oscilloscope across load resistance and observe waveform.


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Waveforms of Class-B Commutation Figure 9


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Experiment 9 Objective : Study of Class C Commutation Circuit Equipments Needed : Equipment Quantity 1. Resistance 2K2, 1/4W 2 2. MET. CAP. 0.1MFD (on board) 1 3. SCR TYN616 2

Circuit diagram : The circuit diagram of class C commutation circuits is as follows:

Class C Commutation Circuit

Figure 10 Procedure : 1. Connect circuit as shown above figure 10. 2. Connect G1 & G2 signal to gate of SCR.

3. Switch ‘On’ the power supply. 4. Connect oscilloscope across SCR and observe waveform.

5. Connect oscilloscope across load resistance and observe waveform.


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Waveforms of Class C Commutation Figure 11


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Experiment 10 Objective : Study of Class D Commutation Circuit Equipments Needed : Equipment Quantity 1. Resistance 511E, 1/4W 1

2. Met. Cap 0.33 MFD (on board) 1 3. SCR 2P4M (on board) 2

4. Inductor 68mH (on board) 1 5. Diode 1N4007 (on board) 1

Circuit diagram : The circuit diagram of class D commutation circuits is as follows :

D Commutation Circuit

Figure 12 Procedure : 1. Make circuit as shown in the figure 12.

2. Connect G1 & G2 signal to gate of SCR1 & SCR2. 3. Switch ‘On’ the power supply.

4. Connect oscilloscope across SCR1& SCR2 and observe waveforms.


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Waveforms of Class-D Commutation

Figure 13


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Experiment 11 Objective : Study of Class-F Commutation Circuit Equipments Needed : Equipment Quantity 1. Resistance 1K,10W (on board) 1

2. SCR 2P4M (on board) 1

Circuit diagram : The circuit diagram of class D commutation circuits is as follows:

Class D Commutation Circuit

Figure 14 Procedure : 1. Connect circuit as shown above figure 14 using patch cords. 2. Connect GR1 signal to gate of SCR.

3. Switch ‘On’ the power supply. 4. Vary the firing control pot and observe waveform across load.

5. Vary the firing control pot and observe waveform across SCR.


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Waveform of Class F Commutation Figure 15


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Experiment 12 Objective : Study of the Resistor Triggering Circuit Equipments Needed : Equipment Quantity

1. Resistance 1K, 1/4W 1

2. Resistance 511E, 1/4W 2 3. Potentiometer 1M (on board) 1

4. SCR 2P4M (on board) 1 5. Diode 1N4007 (on board) 1

Circuit diagram : The circuit diagram for SCR Triggering circuits is as follows:

Resistance Triggering Circuit Figure 16

Procedure : 1. Make circuit as shown in the figure 16 using patch cords 2. Rotate the potentiometer P1 fully in the CW (clockwise direction).

3. Switch ‘On’ the power supply. 4. Connect the oscilloscope CHI across the load and observe the Phase angle and

voltage. 5. Now, connect the oscilloscope probe across the thyristor and observe the

waveform. 6. Vary the potentiometer slowly; you can see the phase angle variation.

7. Repeat the experiment from step 5 for various angles and plot the graphs by T = (α X 10ms) / 180


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S.No. Load voltage(V)

Phase Angle (α)

1.

2.

3.

4.

5.

6.

Waveforms of R Firing Circuit

Figure 17


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Experiments 13

Objective : Study of the Resistor-Capacitor Triggering Circuit (Half Wave)

Equipments Needed :

Equipment Quantity


2. Potentiometer 1M (on board) 1


4. Diode 1N4007 (on board ) 2

5. Met. Cap. 0.1 MFD(on board) 1

Circuit diagram :

The circuit diagram for SCR Triggering circuits is as follows:

Resistor-Capacitor Triggering Circuit Figure 18

Procedure : 1. Make circuit as shown in the figure 18 using patch cords. 2. Rotate the potentiometers P fully in the CCW (Anticlockwise direction).

3. Switch ‘On’ the power supply. 4. Connect the oscilloscope probe between the load test point TP3 and TP4 and

observe the Phase angle and voltage. 5. Now, connect the oscilloscope probe across the thyristor and observe the

waveform. 6. Vary the potentiometer slowly; you can see the phase angle variation.

7. Repeat the experiment from step 5 for various angles and plot the graphs. T = (α X 10ms) / 180


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Observation Table :

S. No. Load voltage(V) Phase Angle (α)

1. 2. 3.

4. 5. 6.

Waveforms of RC Half Wave Firing Circuit

Figure 19


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Experiment 14 Objective : Study of the Resistor-Capacitor Triggering Circuit (Full Wave) Equipments Needed : Equipment Quantity

1. Resistance 511E, 1/4W 1

2. Resistance 1K, 1W (on board) 1 3. SCR 2P4M (on board) 1

4. POT 1M (on board) 1 5. Ele. Cap 1MFD (on board) 1

6. Diode 1N4007 4

Circuit diagram : The circuit diagram for SCR Triggering circuits is as follows:

Resistor - Capacitor Triggering Circuit Figure 20


2. Rotate the potentiometers P fully in the CW (clockwise direction). 3. Switch ‘On’ the power supply.

4. Connect the oscilloscope probe between the load test point TP5 and TP6 and observe the Phase angle and voltage.

5. Now, connect the oscilloscope probe across the thyristor and observe the waveform.


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6. Vary the potentiometer slowly; you can see the phase angle variation. 7. Repeat the experiment from step 5 for various angles and plot the graphs.

T = (α X 10ms) / 180

Observation Table :

S. No. Load voltage (V) Phase Angle (α)

1. 2. 3.

4. 5. 6.

Waveform of RC Full Wave Firing Circuit

Figure 21


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Experiment 15 Objective : Study of the triggering of SCR using UJT Equipments Needed : Equipment Quantity


2. Resistance 47E, 1/4W 1 3. Resistance 100E, 2W 1

4. Resistance 220E, 1/4W 1 5. Potentiometer 5K 2

6. Ele. cap 1MFD (on board) 1 7. UJT 2N2646 (on board) 1

8. SCR TYN 616(on board) 1

Circuit diagram : The circuit diagram for Triggering of SCR using UJT is shown in figure 22.

Triggering SCR using UJT

Figure 22


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2. Connect Ammeter between points‘3’ and ‘4’ to measure Anode-cathode current IAK (mA).

3. Connect Ammeter between points ‘1’ and ‘2’ to measure the gate Current IG (mA).

4. Connect voltmeter between point ‘5’ and ground to measure the anode-cathode voltage VAK.

5. Rotate the potentiometer P1 fully in clockwise direction and P2 fully in the CCW (counter clockwise direction).

6. Switch ‘On’ the power supply. 7. Vary the potentiometer P2 in clockwise direction so as to increase the anode to

cathode voltage. Set this voltage above 11V. 8. Vary the potentiometer P1 in counterclockwise direction so as to increase the

value of gate current in step and measure the corresponding values of anode to cathode current IAK in an observation table 1.

9. Initially there will not be any current flow across the SCR, while varying the gate current the ammeter connected at point ‘c’ and‘d’ suddenly increases and the voltmeter connected at point ‘e’ and ground will suddenly decrease. This shows that the SCR is triggered.

10. Now vary the POT1, there will not be any effect in the anode –cathode voltage and current of SCR.

11. To repeat the experiment switch off the power supply and follow the above procedure from step 6.

Observation table : Set VAK = +12V

S. No.

Gate current IG (mA)

Anode to cathode current IAK (mA)

Anode to cathode voltage VAK (V)


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Experiment 16 Objective : Study of the Triggering of SCR using 555 IC Equipments Needed : Equipment Quantity


2. Resistance 100E, 2W 1 3. Resistance 5K, 1/4W 1

4. IC 555 timer 1 5. Capacitor 0.01MFD 1

6. Ele. Cap 1MFD (on board) 1 7. Diode 1N4007 (on board) 1

8. SCR TYN 616(on board) 1 9. Potentiometer 5K 2

Circuit diagram : The circuit diagram for Triggering of SCR using 555 IC is as follows:

Triggering of SCR using 555 IC Figure 23


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2. Connect Ammeter between points ‘3’ and ‘4’ to measure Anode-cathode current IAK (mA).

3. Connect Ammeter between points ‘1’ and ‘2’ to measure the gate Current IG (mA).


5. Rotate the potentiometer P1 fully in clockwise direction and P2 fully in the CCW (counter clockwise direction).

6. Switch ‘On’ the power supply. 7. Vary the potentiometer P2 in clockwise direction so as to increase the anode to

cathode voltage. Set this voltage above 11V. 8. Vary the potentiometer P1 in counterclockwise direction so as to increase the

value of gate current in step and measure the corresponding values of anode to cathode current IAK in an Observation table 1.

9. Initially there will not be any current flow across the SCR while varying the gate current the ammeter connected at point ‘3’ and ‘4’ suddenly increases and the voltmeter connected at point ‘5’ and ground will suddenly decrease. This shows that the SCR is triggered.

10. Now vary the POT1, there will not be any effect in the anode –cathode voltage and current of SCR.

11. To repeat the experiment switch off the power supply and follow the procedure from step 6.

Observation Table : Set VAK = +12V

S. No.

Gate current IG (mA)

Anode to cathode current IAK (mA)

Anode to cathode voltage VAK (V)


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Experiment 17 Objective : Study of the Triggering of SCR using Op-Amp 741 IC Equipments Needed :

Equipment Quantity 1. Resistance 10K, 1/4W 3

2. Resistance 120E, 5W (on board) 1 3. Zener 10V 1

4. SCR TYN 616 (on board) 1 5. Potentiometer 5K 2

6. IC lm741 1 7. Met cap 0.047MFD 1

Circuit diagram : The circuit diagram for Triggering of SCR using 74121 IC is shown in below figure 24.

Triggering of SCR using Op-Amp 555 IC Figure 24


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2. Connect Ammeter between point ‘3’ and ‘4’ to measure Anode-cathode current IAK (mA).

3. Connect Ammeter between point ‘1’ and ‘2’ to measure the gate Current IG (mA).


5. Rotate the potentiometer P1 and P2 fully in the clockwise direction. 6. Switch ‘On’ the power supply.

7. Vary the potentiometer P2 in anti clockwise direction so as to increase the anode to cathode voltage. Set this voltage above 11V.

8. Vary the potentiometer P1 in clockwise direction so as to increase the value of gate current in step and measure the corresponding values of anode to cathode current IAK in an Observation Table 1.

9. Initially there will not be any current flow across the SCR while varying the gate current the ammeter connected at point ‘3’ and ‘4’ suddenly increases and the voltmeter connected at point ‘5’ and ground will suddenly decrease. This shows that the SCR is triggered.

10. Now vary the POT1, there will not be any effect in the anode–cathode voltage and current of SCR.

11. To repeat the experiment switch off the power supply and follow the procedure from step 4.


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Experiment 18 Objective : Study of the Ramp and Pedestal Triggering using Anti-Parallel SCR in AC Load Equipments Needed : Equipment Quantity 1. Resistance 220E, 2W 1

2. Resistance 20K, 1/4W 1 3. Resistance 200E, 1/4W 1

4. Resistance 1K, 1W (on board) 1 5. Ele. Cap 1MFD (on board) 1

6. Diode 1N4007 (on board) 5 7. Zener 9V 1

8. Potentiometer 10K 1 9. UJT 2N2646 (on board) 1


11. Pulse transformer 1:1:1 (on board) 1

Circuit diagram : The circuit diagram of basic anti-parallel SCR in AC load is shown in the below figure.

Ramp & Pedestal Triggering using Anti - Parallel SCR

Figure 25


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2. Rotate the potentiometer P1 fully in clockwise direction. 3. Connect the circuit as shown in the figure above using 2mm patch cords.

4. Switch ‘On’ the power supply.

5. Connect the oscilloscope and observe the output waveform across the Load resistor.

6. Set the firing angle at 30º, 60º, 90º, 120º, and 150º by varying the pot P1 and note the reading of output voltage. Angle in time convert using T = (α X 10ms) / 180 .

7. Observe the output waveform across load and across SCRs at firing angle is 90º and Plot the waveforms.

Observation Table :

Output across AC load circuit

S. No.

Input AC voltage

(Vrms)

Firing angle (Degree)

Output voltage (Vrms)


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Waveforms of Ramp and Pedestal Circuit Figure 26


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Experiment 19 Objective : Study of the UJT Relaxation Oscillator Equipments Needed : Apparatus Quantity 1. Resistance 12K1, 1/4W 1

2. Resistance 220E, 1/4W 1 3. Resistance 100E, 1/4W 1

4. Diode 1N4007 1 5. Met. Cap. 0.1MFD (on board) 1

6. UJT 2N2646 (on board) 1

Circuit diagram : Circuit diagram of UJT relaxation oscillator is given below :

UJJ Relaxation Oscillator

Figure 27 Procedure : 1. Make circuit as shown in the figure 27 using patch cords.

2. Rotate the potentiometer P1 fully in clockwise direction. 3. Switch ‘On’ the power supply.


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4. Connect the oscilloscope CHI between output and ground and CHII between TP1 and ground and observe the waveform of pulse output and RC time constant.

5. Vary the potentiometer P1 in clockwise direction so as to increase the frequency of the output.

6. Sketch the waveforms on the paper.

Observation Table :

S. No.

Minimum Frequency (Hz)

Maximum Frequency (Hz)

Waveform of UJT Relaxation Oscillator

Figure 28


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Experiment 20 Objective : Study of the Voltage Commutated Chopper Equipments Needed : Equipment Quantity 1. Resistance 511E, 1/4W 1

2. Met. Cap. 0.33MFD (on board) 1 3. Inductor 68mH(on board) 1

4. Inductor 10mH (on board) 1 5. SCR 2P4M (on board) 2

6. Diode 1N4007 (on board) 2

Circuit diagram : Circuit diagram of voltage commutated chopper is given below :

Voltage Commutated Chopper

Figure 29 Procedure : 1. Make circuit connection as shown above figure 29.

2. Connect G1& G2 to the gate of SCR1 and SCR2. 3. Switch ‘On’ the power supply.

4. Vary the PWM Potentiometer in fully clock wise direction. 5. Vary the frequency pot and observe the output across load and across SCR1&

SCR2. 6. Sketch the waveforms on the paper.


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Observation Table :

S. No. Frequency (Hz) Output voltage

(V)

Waveforms of Voltage Commutated Chopper

Figure 30


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Experiment 21 Objective : Study of the Bedford Inverter Equipments Needed : Equipment Quantity 1. Resistance 30K, 1/4W 1

2. Met. Cap 1MFD 4 3. SCR 2P4M (on board) 4

4. Diode 1N4007 (on board) 4

Circuit diagram : Circuit diagram of Bedford inverter is given below :

SCR1, SCR2, SCR3, SCR4 =2P4M

C1, C2, C3, C4, = MET. 1µF/25V D1, D2, D3, D4 = 1N4007

Bedford Inverter

Figure 31


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Procedure : 1. Make circuit connection as shown above figure 31

2. Connect G1& G2 to the gate of SCR1 and SCR2. 3. Switch ‘On’ the power supply.

4. Rotates the PWM Potentiometer in fully clock wise direction.

5. Vary the frequency pot and observe the output across load and across SCR1& SCR2.

6. Sketch the waveforms on the paper.

Observation Table :

S. No.

Frequency (Hz)

Output voltage (V)


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Experiment 22 Objective : Study of the Single Phase PWM Inverter using MOSFET and IGBT Equipments Needed : Equipment Quantity 1. MOSFET IRFZ 44N 4

2. IGBT G4BC20S 4 3. Resistance 1K, 1/4W 1

4. Tiny toggle switch 1P-2W 1

Circuit diagram :

Figure 32

Single Phase PWM Inverter

Figure 33 Procedure : 1. Make the circuit shown in the figure 32.

2. Rotate the frequency potentiometer in fully anticlockwise direction and PWM pot in fully clockwise direction.


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3. Switch ‘On’ the power supply. 4. Vary the frequency pot and observe waveform across load on oscilloscope.

5. Set the maximum frequency by frequency pot. 6. Vary PWM potentiometer and observe output waveform across load and note

the readings of pulse width and corresponding output AC (rms) voltage across load.

7. Switch off the power supply. 8. Make a circuit as shown in the figure 33. And repeat from step 2.

9. Sketch the waveforms of gate pulse and output pulse across the load. Observation table :

S.

No.

Pulse width

(ms)

AC output voltage across load (MOSFET)

(volts)

AC output voltage across load

(IGBT) (volts)

Waveform of PWM Inverter

Figure 34


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Experiment 23 Objective : Study of the Half – Wave Controlled Rectifier with Resistive Load Equipments Needed : Equipment Quantity 1. SCR 2P4M (on board) 1

2. Resistance 1K, 10W (on board) 1 3. Resistance 270E, 5W (on board) 1

4. Inductor 68mH (on board) 2

Circuit diagram : The circuit diagram of basic half-wave controlled rectifier is shown in the below figure 35

Half – Wave Controlled Rectifier Figure 35


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Procedure :

• Make the circuit shown in the figure 35. 1. Rotate the firing control pot in full clockwise direction.

2. Switch ‘On’ the power. 3. Measure the ac voltage (Vrms) by voltmeter between point 0V-15V and

calculate Em by Em =1.414 X Vrms. 4. Switch ‘Off’ the power.

5. Connect the circuit of half-wave rectifier as shown figure 36. 6. Switch ‘On’ the power.

7. Connect the oscilloscope and voltmeter across the load. 8. Vary the firing control pot and set on 30º, 60º, 90º, 120º and 150º firing angles

using T = (α X 10ms) / 180. 9. Observe the output waveforms and note the readings of voltage across load on

different firing angles. 10. Observe the waveform across the SCR1 when firing angle is 90º.

11. Calculate the average load IDC current and power PDC from measured load voltage Vo.

12. Plot the input signal, gate pulse, and drop signal across SCR and output waveforms when firing angle is 90º.


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(PD

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tion

Tabl

e :


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Waveform of Half Wave Rectifier with Resistive Load Figure 36


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Waveform of Half Wave Rectifier with Resistive- Inductive Load Figure 37


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Experiment 24 Objective : Study of the Full – Wave Controlled Rectifier (mid-point configuration) with Resistive Load. Equipments Needed : Equipment Quantity 1. SCR 2P4M (on board) 2 2. Resistance 1K, 10W (on board) 1

3. Resistance 270E, 5W (on board) 1 4. Inductor 68mH (on board) 2

Circuit diagram : The circuit diagram of basic full – wave controlled rectifier (mid- point configuration) is shown in the below figure 38

Full – Wave Controlled Rectifier

Figure 38


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Procedure :

• Make connections according to figure 38. 1. Rotate the firing control Potentiometer in full clockwise direction.

2. Switch ‘On’ the power. 3. Measure the ac voltage (Vrms) by voltmeter between point 0V-18V and

calculate Em by Em =1.414 X Vrms. 4. Switch ‘Off’ the power.

5. Connect the circuit of full-wave controlled rectifier (mid-point configuration) as shown figure 9 using 2 mm patch cords.

6. Switch ‘On’ the power. 7. Connect the oscilloscope and voltmeter across the load.

8. Vary the firing control pot and set on 30º, 60º, 90º, 120º and 150º firing angles using T = (α X 10ms) / 180.

9. Observe the output waveforms and note the readings of voltage across load on different firing angle.

10. Connect the oscilloscope one by one across SCR1 and SCR2 and observe the waveform when firing angle is 90º.

11. Calculate the average load IDC current and power PDC from measured load voltage Vo.

12. Plot the input signal, gate pulse, and drop signal across SCR and output waveforms when firing angle is 90º.


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Cal

cula

ted

(PD

C)

VD

C X

I DC

Ave

rage

Out

put P

ower

Mea

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d Po

V

o X

Io

Cal

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ted

(ID

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VD

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Ave

rage

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d Cu

rren

t (I

DC)

Mea

sure

d (I

o)

Vo

/ RL

Cal

cula

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Vol

tage

(V

DC)

Ave

rage

Out

put V

olta

ge

A

cros

s Loa

d

Mea

sure

d V

olta

ge

(Vo)

In

Tim

e (m

s)

Firin

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ngle

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Deg

.

In

(VM

)

Inpu

t AC

Vol

tage

In

(VRM

S)

S.

No.

O

bser

vatio

n Ta

ble

:


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Waveform of Full Wave Rectifier (mid-point) with Resistive Load

Figure 39


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Waveform of Full Wave Rectifier (mid-point) with Resistive-Inductive Load

Figure 40


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Experiment 25 Objective : Study of the Fully Controlled Bridge Rectifier with Resistive Load Equipments Needed : Equipment Quantity 1. SCR 2P4M (on board) 4

2. Resistance 1K, 10W (on board) 1 3. Resistance 270E, 5W (on board) 1

4. Inductor 68mH (on board) 2

Circuit diagram : The circuit diagram of basic fully controlled bridge rectifier is shown in the below figure 41

Controlled Bridge Rectifier Figure 41


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Procedure : 1. Rotate the firing control Potentiometer in full clockwise direction. 2. Switch ‘On’ the power. 3. Measure the ac voltage (Vrms) by voltmeter between point 0V-15V and

calculate Em by Em =1.414 X Vrms. 4. Switch ‘Off’ the power. 5. Connect the circuit of fully-controlled bridge rectifier as shown figure 42 using

2 mm patch cords. 6. Switch ‘On’ the power. 7. Connect the oscilloscope and voltmeter across the load. 8. Vary the firing control pot and set on 30º, 60º, 90º, 120º and 150º firing angles

using T = (α X 10ms) / 180 . 9. Observe the output waveforms and note the readings of voltage across load on

different firing angle. 10. Connect the oscilloscope one by one across SCR1, SCR2, and SCR3 & SCR4

and observe the waveforms when firing angle is 90º respectively. 11. Calculate the average load IDC current and power PDC from measured load

voltage Vo. 12. Plot the input signal, gate pulse, and drop signal across SCR and output

waveforms when firing angle is 90º with resistive and resistive-inductive load.


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Cal

cula

ted

(PD

C)

VD

C X

I DC

Ave

rage

Out

put P

ower

Mea

sure

d Po

V

o X

Io

Cal

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(ID

C)

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C /

RL

Ave

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d Cu

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t (I

DC)

Mea

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d (I

o)

Vo

/ RL

Cal

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Vol

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(V

DC)

Ave

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Out

put V

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A

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s Loa

d

Mea

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d V

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(Vo)

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Tim

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Firin

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In

Deg

.

In

(VM

)

Inpu

t AC

Vol

tage

In

(VRM

S)

S.

No.


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Waveform of Full Wave Bridge Rectifier with Resistive Load

Figure 42


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Waveform of Full Wave Bridge Rectifier with Resistive - Inductive Load

Figure 43


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Data Sheets


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Warranty 1. We guarantee the product against all manufacturing defects for 24 months from

the date of sale by us or through our dealers. Consumables like dry cell etc. are not covered under warranty.

2. The guarantee will become void, if

a) The product is not operated as per the instruction given in the operating manual.

b) The agreed payment terms and other conditions of sale are not followed.

c) The customer resells the instrument to another party. d) Any attempt is made to service and modify the instrument.

3. The non-working of the product is to be communicated to us immediately giving full details of the complaints and defects noticed specifically mentioning the type, serial number of the product and date of purchase etc.

4. The repair work will be carried out, provided the product is dispatched securely packed and insured. The transportation charges shall be borne by the customer.

List of Accessories

1. Bread Boards ........................................................................................... 2 Nos.

2. Connecting Wires .................................................................................. 20 Nos.

3. 2mm to 1mm Patch Cords ..................................................................... 15 Nos.

4. 2mm Patch Cords (Red) .......................................................................... 4 Nos. 5. 2mm Patch Cords (Black)........................................................................ .4 Nos.

6. 2mm Patch Cords (Blue) ....................................................................... 12 Nos. 7. Mains Cord ................................................................................................1 No.

8. e-Manual....................................................................................................1 No.

Updated 20-04-2009


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List of other Trainers available from us are : Model Name PE01 UJT Characteristics PE02 MOSFET Characteristics PE03 SCR Characteristics PE04 TRIAC Characteristics PE05 DIAC Characteristics PE06 IGBT Characteristics PE07 PUT Characteristics PE10 SCR Triggering (R, RC Full wave, RC Half wave) PE11 SCR Triggering (UJT) PE12 SCR Triggering (IC555) PE13 SCR Triggering (IC74121) PE14 Ramp and Pedestal Triggering PE15 SCR Triggering (IC741) PE16 SCR Triggering (PUT) PE40 SCR Lamp Flasher PE41 SCR Alarm Circuit PE42 Series Inverter PE43 UJT Relaxation Oscillator PE44 Single Phase PWM Inverter ST2701 IGBT Characteristics ST2702 SCR Triggering (R, RC Half wave, RC Full wave) ST2703 SCR Triggering Techniques ST2704 Triggering of SCR using 74121 IC ST2705 SCR Lamp Flasher ST2706 SCR Alarm Circuit ST2707 Series Inverter ST2708 Single Phase Controlled Rectifier (with Ramp Comparator Firing

Scheme) ST2709 Single Phase Controlled Rectifier (Cosine Firing Scheme) ST2710 Single Phase Converter Firing Techniques (by TCA 785IC and

Triangular Comparator) ST2711 Lamp Dimmer ST2712 Electronics Power Lab ST2713 Single Phase Cyclo-Converter ST2714 Speed Control of Universal Motor using SCR ST2715 Speed Control of AC Motor using TRIAC ST2716 Microcontroller Based Firing Circuit for Controlled Rectifier ST2717 SCR Commutation Circuits ST2718 Bedford & Parallel Inverter ST2719 Step-Up Chopper ST2720 Single Phase Bridge Inverter ST2722 Step-Down Chopper ST2723 AC Chopper


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