Download experiment 2-3 full

EXPERIMENT 2-3 FULL-WAVE BRIDGE
The bridge rectifier is one of the most commonly used types of power supplies. This experiment will
familiarize you with it.
EQUIPMENT
• (4) silicon rectifiers, or a bridge rectifier assembly
• (2) capacitors, 100 µF at 25 WVDC (Use in || for the 200µF Cap in the circuit)
• transformer, V„, = 12.6 VCT at 100 mA or greater
• 1/2-W 10% resistors
• oscilloscope
• VOM
• line cord
• plug
• power switch
PROCEDURE
1.
Build the circuit above, it should look like the pictures below. Apply power and measure the
output voltage, ripple, and frequency. The values shown are normal, if yours aren’t close – there is a
problem with your circuit. Record your values.
Vo = 17.8VDC, ______________ Vrip = 0.75 Vp-p _________________
Frequency of the ripple voltage =
Sketch your ripple voltage over the sample and show voltage and time units on the sketch.
Volts
time
Based upon Experiment 2-3 from Electronic Troubleshooting, Jerome Oleksy, 2nd edition - 1990, Glencoe. Modifications for
CSN’s ET 289B class.
Red and black wires on right connected to a VOM. White and grey wires connected to an O-Scope.
The spacing is critical for the modifications made during the experiment.
2. Remove one of the two Caps so that C1 = 100 µF and measure the values again.
Vo =
Vrip =
Frequency of the ripple voltage =
Based upon Experiment 2-3 from Electronic Troubleshooting, Jerome Oleksy, 2nd edition - 1990, Glencoe. Modifications for
CSN’s ET 289B class.
3. Add another 1K ohm resistor in parallel with the load resistor and measure the values again.
Vo =
Vrip =
Frequency of the ripple voltage =
4. Reinsert the Cap removed in step 2 above (C1 now equals 200µF) 200µF
Vo =
Vrip =
Frequency of the ripple voltage =
5. Remove the parallel resistor added in step 3 and ensure the measurements return to the values is
step 1.
6. Remove diode D2 and measure the values again.
Vo =
Vrip =
Frequency of the ripple voltage =
Sketch the ripple voltage and show voltage and time data on the sketch.
7. Leave diode D2 out of the circuit and remove diode D3 and measure the values again.
Vo =
Vrip =
Frequency of the ripple voltage =
8. Replace diode D2 and remove diode D1 . Measure the values again.
Vo =
Vrip =
Frequency of the ripple voltage =
9. Replace diodes D1 and D3 . Ensure that you have the same values as measured in step 1.
Based upon Experiment 2-3 from Electronic Troubleshooting, Jerome Oleksy, 2nd edition - 1990, Glencoe. Modifications for
CSN’s ET 289B class.
10. Move the black lead supplying power to the circuit from the 12.6 VAC power supply to the center
tap on the 12.6 VAC power supply. Your circuit should match the one below. Measure the values
again.
Vo =
Vrip =
Frequency of the ripple voltage =
Sketch the ripple voltage and show voltage and time data on the sketch.
11. Put another 1K ohm resistor in parallel with the load resistor. Measure the values again.
Vo =
Vrip =
Frequency of the ripple voltage =
12. Remove the resistor added in the above step and remove diode D2. Measure the values again.
Vo =
Vrip =
Frequency of the ripple voltage =
Based upon Experiment 2-3 from Electronic Troubleshooting, Jerome Oleksy, 2nd edition - 1990, Glencoe. Modifications for
CSN’s ET 289B class.
QUIZ
1. A bridge circuit based power supply has –(a) more, (b) less, (c.) same amount of ripple as a ½
wave rectifier based power supply.
2.
When observing the output voltage with an oscilloscope, how can you tell if the circuit is a
bridge or ½ wave rectifier?
3. How would you change the circuit in Figure E2-3on page 31 of the textbook into a dual (+)
supply? Draw the circuit below.
4. Describe the operation of the circuit in Figure E2-4C on page 34 of the textbook. Specifically is
it a bridge rectifier or something else.
5. What is the function of D1 and D2 in Figure E2-4C on page 34 of the textbook?
6. What is the function of D3 and D4 in Figure E2-4C on page 34 of the textbook?
7. If D1 in Figure E2-4C on page 34 is opened, how would the outputs be affected?
Based upon Experiment 2-3 from Electronic Troubleshooting, Jerome Oleksy, 2nd edition - 1990, Glencoe. Modifications for
CSN’s ET 289B class.