Introduction:

Lab is based on the lab form the previous week on half-wave and full-wave rectifiers and taking that knowledge to build a bridge rectifier.

Materials and Equipment:

Materials:

• Simulated Parts (Multisim):
  • A 30/3 Vrms center-tapped transformer
  • Two diodes 1N4001
  • Two 2.2 kΩ resistors
  • One 100 μF, 50 V electrolytic capacitor (any voltage rating is fine since is simulation only)
  • One fuse (any rating is fine since is simulation only)

Equipment:

• Virtual Instruments (Multisim):
  • Tektronix Oscilloscope
  • Agilent Multimeter
  • Agilent Function generator

Procedure:

*** This lab has to be implemented only in software (running simulations on Multisim) ***

1. Construct the bridge rectifier circuit shown in Figure 1. Notice that no terminal of the transformer secondary is at ground potential (some simulation software will not run if it is not connected to the ground, check yours). The input voltage to the bridge, V_SEC, is not referenced to ground. Make sure to include resistor tolerance of 5%.
2. Use a function generator to provide V_AC and run the simulation.
3. Use a multimeter to measure V_SEC (rms) and then use the oscilloscope to measure the peak output voltage (V_LOAD) without a filter capacitor. Tabulate all data gathered.

Figure 1

4. Connect the 100 μF capacitor in parallel with the load resistor. Measure V_LOAD, the peak-to-peak ripple voltage V_RIPPLE, and the ripple frequency. Tabulate all data gathered and compare the results with and without the filter capacitor.

5. Choose a diode among the four connected to the bridge and open it. Simulate an open diode in the bridge and explain what happens to the output voltage, the ripple voltage and the ripple frequency?
6. Investigate the effect of the load resistor on the ripple voltage by connecting a second 2.2 kΩ, 5% tolerance, and load resistor in parallel with R_L and C₁ in the full-wave circuit of Figure 3. Measure the ripple voltage. Captures a screenshot.

Review questions:

1. Compare a bridge rectifier circuit with full-wave rectifier center-tapped circuit which you did in Lab 2. Which circuit has the higher output voltage?
2. Explain how you could measure the ripple frequency to determine if a diode were open in a bridge rectifier circuit.
3. What is the maximum dc voltage you could expect to obtain from a transformer with a 3 Vrms secondary using a bridge circuit with a filter capacitor?

Deliverables:

1. Measure the voltage V_SEC and the output load voltage, V_LOAD without a filter capacitor. Capture the screenshots of your measurements.
2. Measure the output load voltage, V_LOAD, with the capacitor and the peak-to-peak ripple voltage, V_RIPPLE, in the output. Capture thescreenshots of your measurements. Also, measure the ripple frequency. Table with all the data gathered for the circuit with and without the capacitor.
3. Follow the template “Lab Report Template” to compile the report and make sure to check the report against the grading rubric below. The template can be found in the “Tools and Templates” link in the navigation center.
4. Make sure to include the table, calculations, screenshots of the measurements and the answer to the questions.