Electronics I – Week #3 Lab 1

Bridge Rectifier

Introduction:

Week 3 lab is based on the previous lab from week 2 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.

	Without the capacitor	With the capacitor
Output load voltage V_LOAD
Peak-to-peak ripple voltage V_RIPPLE
Ripple frequency

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 the screenshots 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. Save the document as Lab2YourGID.docx (ex: Lab3G00000000.docx).

Rules for lab submissions:

1. The lab document must be a Word document. PDF files are NOT accepted.

2. All screenshots must be included.

3. All Multisim screenshots must include the date/time stamp. See TOOLS AND TEMPLATES for the procedure to display the date and time.

4. Any and all Multisim files must be submitted.

5. Any equations used must be typed in Word. Copy and paste of equations from outside sources is prohibited.

6. No graphics are allowed in the Word document other than screenshots of circuits from Multisim and hardware if applicable, with the date/time stamp.

7. The lab template should be used. Specifically, it is brought to your attention that a summary MUST be provided explaining the results of the labs, the relationship of the results to expected results, and any challenges encountered.

8. Hardware portion of labs should include screenshots of the assembled circuit with your name and student GID number written on paper next to the circuit. There should be screenshots of the instrument readings with the date and time stamp on lower right corner clearly shown.

Any violation of the submission rules above will result in a grade of 1.

Grading Criteria	Points
Construct bridge rectifier circuit in Multisim without a capacitor	15
Measurement of V_SEC and V_LOAD voltages with screenshots	10
Construct bridge rectifier circuit in Multisim with a capacitor	10
Measurement of V_SEC, V_LOAD and V_RIPPLE voltages with screenshots	15
Simulation with an open diode and measurement with screenshots	20
Including 5% tolerances in the measurements	10
Review Questions	10
Report format (Proper use of template)	10
TOTAL	100