Pre-Lab Information

Rectifiers are widely used in power supplies to provide the required dc voltage.

Materials and equipment Needed:

Materials:

•One 240/24 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:

•Oscilloscope.
•Function generator.

Procedure:

In this experiment, use Multisim to connect a low-voltage (24 V ac) transformer to a 240V 50Hz ac line (use the function generator for simulation and consider whether the typical specification is peak or rms). Connect the half-wave rectifier shown in Figure 1. Notice the polarity of the diode. Be sure to set the tolerance of the resistor to 5%. Connect the oscilloscope so that channel 1 is across the transformer and channel 2 is across the load resistor. View the secondary voltage, VSEC, and the load voltage, VLOAD, for this circuit and observe their waveforms.

1.Measure the rms input voltage VSEC to the diode (remember to convert the oscilloscope reading of VSEC to rms) and the output peak voltage, VLOAD. Tabulate all data gathered. Capture screenshots of your measurements..

2.The output isn't very useful as a dc source because of the variations in the output waveform. Connect a 100 μF capacitor (C1) with a tolerance of 10% in parallel with the load resistor (RL). (note the polarity of the capacitor). Measure the dc load voltage, VLOAD, and the peak-to-peak ripple voltage, VRIPPLE, in the output. Measure the ripple frequency. Capture screenshots. Tabulate all data gathered and compare the results with and without the filter capacitor..

3.Disconnect the power and change the circuit to the full-wave rectifier circuit shown in Figure 2. Notice that the ground for the circuit has changed. The oscillopscope ground needs to be connected as shown. Check your circuit carefully before applying power. Compute the expected peak output voltage. Then apply power and view the VSEC and VLOAD waveforms..

Measure the VSEC rms and peak output voltage VLOAD without a filter capacitor. Capture screenshots of the waveforms.

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

5.Investigate the effect of the load resistor on the ripple voltage by connecting a second 2.2 kΩ, 5% tolerance, load resistor in parallel with RL and C1 in the full-wave circuit of Figure 3. Measure the ripple voltage. Captures a screenshot..

6.Conclusion: Write a detailed conclusion about this lab experiment. The conclusions should explain in detail and in words why the results were different at different stages in the lab and what the implications are of the different results. You should make sure that you include the following:

a.the effect of capacitor on the output voltage.

b.and the effect of additional load on the ripple voltage.

Please note, however, that addressing only a and b will not result in full points.

7.Evaluation and Review Question:.

What advantage does a full-wave rectifier circuit have over a half-wave rectifier circuit?