INC 253 Digital and electronics laboratory I
Laboratory 5
Basic DC Power Supply
Author:
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Co-Authors:
1. …………………………… ID …………………
2. …………………………… ID …………………
3. …………………………… ID …………………
Experiment Date: ………………… Report received Date: …………………
For Instructor
Comments
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Pre lab
Full
10
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Results
15
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Discussion
Questions
Conclusion
25
10
5
Total
65
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Marks
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Department of Control System and Instrumentation Engineering
Faculty of Engineering
King Mongkut’s University of Technology Thonburi
Objectives
1. To understand the basic DC power supply both half wave and full wave rectifier.
2. To understand the filter and the regulator circuit.
3. To understand the effect of load.
Equipments Required
1. Basic DC power supply experiment circuit board
2. Multimeter
3. Oscilloscope
*** NOTE ***
1. Do not measure the transformer input by using oscilloscope.
2. Checking your circuit carefully before connected to power line.
3. Set both of ground position (CH1 and CH2) are the same position.
4. Set the vertical input coupling of your oscilloscope to DC coupling.
5. For more information about clipping and clamping circuits, please use
reference books same as in INC 225.
Pre-Lab Preparation
1. Half Wave Rectifier Circuit
D1
220Vrms
RL
10:1
Fig.1 Half wave rectifier circuit.
Volt/Div_____ Time/Div______
Calculate and plot the voltage across load RL as shown in Fig.1 compared with the transformer
output signal in the same graph.
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Lab. 5: Basic DC Power Supply
2. Center Tapped Full Wave Rectifier Circuit
D1
220Vrms
RL
10:1
D2
Fig.2 Center tapped full wave rectifier circuit.
Volt/Div_____ Time/Div______
Calculate and plot the voltage across load RL as shown in Fig.2 compared with the transformer
output signal in the same graph.
3. Bridge Full Wave Rectifier Circuit
220Vrms
RL
10:1
Fig.3 Bridge full wave rectifier circuit.
Volt/Div_____ Time/Div______
Calculate and plot the voltage across load RL as shown in Fig.3 compared with the transformer
output signal in the same graph.
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Lab. 5: Basic DC Power Supply
4. Filter Circuit
D1
220Vrms
C
RL
10:1
Fig.4 Filter circuit.
Volt/Div_____ Time/Div______
Calculate and plot the voltage across load RL as shown in Fig.4 compared with the transformer
output signal in the same graph.
Procedure
1. Half Wave Rectifier Circuit
1.1. Construct the circuit as shown in Fig.5, using RL = 120Ω as a load.
D1
220Vrms
RL
Fig.5 Half wave rectifier circuit.
RL = 120Ω
Volt/Div_____ Time/Div______
RL = 2kΩ
Volt/Div_____ Time/Div______
average voltage_______________
average voltage_______________
average current_______________
average current_______________
peak inverse voltage___________
peak inverse voltage___________
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Lab. 5: Basic DC Power Supply
1.2. Measure the transformer output voltage with multimeter and use oscilloscope to
measure and plot its waveform.
1.3. Measure the voltage across diode (D1) with multimeter and use oscilloscope to
measure and plot its waveform. (Compare with 1.2)
1.4. Measure the voltage across load (RL) with multimeter and use oscilloscope to
measure and plot its waveform. (Compare with 1.2)
1.5. Calculate average voltage, average current and peak inverse voltage.
1.6. Change load RL to 2kΩ, repeat experiment 1.2 to 1.5.
2. Center Tapped Full wave rectifier circuit
2.1. Construct the circuit as shown in Fig.6, using RL = 120Ω as a load.
D1
220Vrms
RL
D2
Fig.6 Center tapped full wave rectifier circuit.
RL = 120Ω
RL = 2kΩ
Volt/Div_____ Time/Div______
Volt/Div_____ Time/Div______
average voltage_______________
average voltage_______________
average current_______________
average current_______________
peak inverse voltage___________
peak inverse voltage___________
2.2. Measure the transformer output voltage with multimeter and use oscilloscope to
measure and plot its waveform.
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Lab. 5: Basic DC Power Supply
2.3. Measure the voltage across diode (D1 and D2) with multimeter and use oscilloscope to
measure and plot its waveform. (Compare with 2.2)
2.4. Measure the voltage across load (RL) with multimeter and use oscilloscope to
measure and plot its waveform. (Compare with 2.2)
2.5. Calculate average voltage, average current and peak inverse voltage.
2.6. Change load R to 2kΩ, repeat experiment 2.2 to 2.5.
3. Bridge Full wave rectifier circuit
3.1. Construct the circuit as shown in Fig.7, using RL = 120Ω as a load
220Vrms
RL
Fig.7 Bridge full wave rectifier circuit.
RL = 120Ω
Volt/Div_____ Time/Div______
RL = 2kΩ
Volt/Div_____ Time/Div______
average voltage_______________
average voltage_______________
average current_______________
average current_______________
peak inverse voltage___________
peak inverse voltage___________
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Lab. 5: Basic DC Power Supply
3.2. Measure the transformer output voltage with multimeter and use oscilloscope to
measure and plot its waveform.
3.3. Measure the voltage across diode with multimeter and use oscilloscope to measure
and plot its waveform. (Compare with 3.2)
3.4. Measure the voltage across load (RL) with multimeter and use oscilloscope to
measure and plot its waveform. (Compare with 3.2)
3.5. Calculate average voltage, average current and peak inverse voltage.
3.6. Change load R to 2kΩ, repeat experiment 3.2 to 3.5.
4. Filter Circuit
4.1. Construct the circuit as shown in Fig.8, using RL = 120Ω as a load and C = 220µF
D1
220Vrms
C
RL
Fig.8 Filter circuit.
RL = 120Ω, C = 220µF
Volt/Div_____ Time/Div______
RL = 120Ω, C = 470µF
Volt/Div_____ Time/Div______
average voltage_______________
average voltage_______________
average current_______________
average current_______________
ripple factor_________________
ripple factor_________________
ripple voltage________________
ripple voltage________________
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Lab. 5: Basic DC Power Supply
4.2. Measure the transformer output voltage with multimeter and use oscilloscope to
measure and plot its waveform.
4.3. Measure the voltage across diode with multimeter and use oscilloscope to measure
and plot its waveform. (Compare with 4.2)
4.4. Measure the voltage across load (RL) with multimeter and use oscilloscope to
measure and plot its waveform. (Compare with 4.2)
4.5. Calculate average voltage, average current, ripple factor and ripple voltage.
4.6. Change C to 470µF, repeat experiment 4.2 to 5.5.
5. Regulator Circuit using Zener Diode
5.1. Construct the circuit as shown in Fig.9, using C=470µF, RS=150Ω, RL=1kΩ
D1
220Vrms
C
RS
RL
Fig.9 Regulator circuit using zener diode.
C=470µF, RS=150Ω, RL=1kΩ
C=470µF, RS=150Ω, RL=120Ω
Volt/Div_____ Time/Div______
Volt/Div_____ Time/Div______
%load regulator_______________
%load regulator_______________
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Lab. 5: Basic DC Power Supply
C=220µF, RS=150Ω, RL=120Ω
Volt/Div_____ Time/Div______
%load regulator_______________
5.2. Measure the voltage across capacitor (C) with multimeter and use oscilloscope to
measure and plot its waveform.
5.3. Measure the voltage across zener diode by using multimeter and oscilloscope both no
load and on load, and plot its waveform. (Compare with 5.2)
5.4. Calculate %load regulator.
5.5. Change load RL to 120Ω, repeat experiment 5.2 to 5.4.
5.6. Change load RL to 120Ω and C to 220µF, repeat experiment 5.2 to 5.4.
6. Regulator Circuit using IC Regulator
6.1. Construct the circuit as shown in Fig.10, using C=2200µF, RL=2kΩ
1
D1
220Vrms
7805 Out
Inin 7805
GND
GNDout
3
2
C
RL
Fig.10 Regulator circuit using IC regulator.
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Lab. 5: Basic DC Power Supply
C = 2200µF, RL = 2kΩ
Volt/Div_____ Time/Div______
%load regulator_______________
C = 2200µF, RL = 120Ω
Volt/Div_____ Time/Div______
%load regulator_______________
6.2. Measure the voltage across capacitor (C), the input voltage of IC regulator, with
multimeter and use oscilloscope to measure and plot its waveform.
6.3. Measure the output voltage of IC regulator (pin 2 and pin 3) by using multimeter and
oscilloscope both no load and on load, and plot its waveform. (Compare with 6.2)
6.4. Calculate %load regulator.
6.5. Change load RL to 120Ω, repeat experiment 6.2 to 6.4.
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Lab. 5: Basic DC Power Supply