8 calculate by using equation 41 9 measure vdc with

8. Calculate by using equation 4.1.
9. Measure Vdc with multimeter and compare results.
(4.1)

24
Figure 4.1 Schematic diagram of half wave controlled rectifier
4.1.1 Calculations

25
4.1.2 Observations
Table 4.1 Observations
S .No
Angle
α
Calculated Measured
Error
1
2
3
4
5
6
7
4.1.3 Input and Output waveforms
Figure 4.2 Input and Output Waveform

26
4.1.4 Conclusion
4.2 Study and perform single phase full wave controlled rectifier.
1. Construct the circuit on bread board which is shown in Fig 4.3.
2. Identify primary and secondary windings of transformer with the help of multimeter.
3. Connect secondary winding of transformer at the input of circuit.
4. Apply 220V AC to primary winding of transformer.
5. Connect oscilloscope across RL.
6. Observe the output wave form and measure angle.
7. By varying variable resistor adjust different firing angles measure the average output
voltages with the help of oscilloscope.
8. Calculate by using equation 4.2.
9. Measure Vdc with multimeter and compare results.
(4.2)
Figure 4.3 Schematic diagram of full wave controlled rectifier

27
4.2.1 Calculations
4.2.2 Observations
Table 4.2 Observations
S .No
Angle
α
Calculated Measured
Error
1
2
3
4
5
6
7

28
4.3.3 Input and Output waveforms
Figure 4.4 Input and Output Waveform
4.3.4 Conclusion

29
EXPERIMENT 5
Main’s synchronized gate firing circuit
Objective
1. To study and perform main‟s synchronized gate firing circuit of an SCR.
Equipment Required
1- Digital Multimeter
2- Oscilloscope
3- Transformer 12V
4- Silicon Controlled Rectifier (SCR)
5- Diode 1N4007
6- Resistors (470Ω, 1kΩ, 10kΩ, 1MΩ)
7- Variable Resistor (5kΩ)
8- Capacitors (100nF, 1000uF)
9- Transistors (TIP122, C1383)
10- Fuse 200mA
11- Connecting wires
12- Breadboard
5.1 Theoretical background
In this lab a pulse width modulation gate firing circuit is studied that takes dc input and
accordingly generate gate firing pulses for an SCR. One of the main component of this circuit is
the synchronization of gate firing pulses with the main‟s power driving the SCR. Block diagram
of complete system is shown in Fig 5.1.
Figure 5.1 Block diagram of complete system

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5.2 Procedure
1. Identify primary and secondary windings of transformer with the help of multimeter.
2. Connect primary winding of transformer to main supply and secondary winding to the
input of bridge rectifier as shown in Fig 5.2.
3. Connect oscilloscope across secondary winding and RL.
4. Apply 220V ac at primary winding of transformer.
5. Observe and analyze input and output wave forms with oscilloscope.
6. Construct zero crossing detector circuit on bread board as shown in Fig 5.4.
7. Connect output of bridge rectifier with the input of zero crossing detector.
8. Common the ground terminal of both circuits.
9. At Vcc terminal we got smooth DC voltages that will be used to provide supply to
integrator circuit.
10. Connect oscilloscope between point B and ground.
11. Observe and analyze output of zero crossing detector with oscilloscope.
12. Construct operational amplifier based integrator circuit on bread board as shown in
Fig5.6.
13. Connect output of zero crossing detector with the input of integrator.
14. Connect Vcc from zero crossing circuit to the Vcc pin of operational amplifier.