Rectifier Circuits
Febuary 20th, 2015
Shane Juman
Partner: Jerson Recarte
EMT 1255 Lab
Prof. Carrington
Experiment # 3
Due Date: 3/6/15
Table of Contents
Topic
Page #
Objective …………………………………………………………… 1
Materials ………………………………………………………….... 1
Predictions …………………………………………………………. 1
Procedure ………………………………………………………….. 1
Observed and Calculated Results …………………………………... 2
Graphic & Schematic Calculations ………………………………… 3-4
Questions …………………………………………………………… 5
Conclusion ………………………………………………………….. 5
Physical Lab Sheet (with signature) ………………………………. 6-8
Objective:
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Compare input and output voltages for half-wave, full-wave and bridge rectifier circuits.
Measure the ripple voltage and frequency when you connect a filter capacitor to each
circuit.
Materials:
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Breadboard
Two 2.2kΩ resistors
One 12.6 V ac center-tapped transformer with fused line cord
Four 1N4001 diodes
One 100µF capacitor.
Predictions: When ac is applied to a diode, the diode is forward-biased one-half of the cycle,
then reverse-biased for the other half. The output we get should be a dc waveform. We could
then use the dc waveform and convert into constant dc form. Then we could find the max peak
inverse voltage and amount of reverse voltage across the diode.
Procedure:
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Connect the half-wave rectifier shown and connect it to the oscilloscope to view and
sketch the waveforms in Plot 3-1.
Measure the secondary rms voltage and output peak voltage.
Connect the 100µF capacitor in parallel with the load resistor. Using the oscilloscope,
measure the ripple frequency.
Disconnect the power and change the circuit to the full-wave rectifier. Then compute the
expected peak output voltage for the circuit.
Measure the rms voltage and peak output voltage without a filter capacitor.
Add a 100µF capacitor in parallel with the load resistor and measure the output dc
voltage, peak-to-peak ripple voltage, and ripple frequency.
Connect a second 2.2kΩ resistor in parallel with the other load resistor and measure the
ripple voltage.
Disconnect power and change the circuit to the bridge rectifier shown and compute the
expected peak output voltage. Use the oscilloscope to measure the peak output voltage
without a filter capacitor.
Connect the 100µF capacitor with the load resistor, and measure the output dc voltage,
peak-to-peak ripple voltage, and ripple frequency.
Calculated Results:
Table 3-1: Half-wave rectifier.
Table 3-2: Full-wave rectifier.
Table 3-3: Bridge Rectifier Circuit.
Graphical and Schematic Results:
Graph on oscilloscope for Figure 3-2. (Vsec in yellow and Vout in blue)
Oscilloscope shown on Multisim for Figure 3-2, Vsec.
Waveforms for Figure 3-3. (Vsec in yellow, Vout in blue)
Waveform of Vsec for Figure 3-3 shown in Multisim.
Questions:
7. The load current affects the ripple voltage by doubling what you measured for Vr(pp).
10. The output voltage will remain the same, the ripple voltage will be twice the amount, and
the ripple frequency will be half.
1. What advantage does a full-wave rectifier circuit have over a half-wave rectifier circuit?
The full-wave rectifier uses both positive and negative peaks while a half-wave connects
just to the ground.
2. Compare a bridge rectifier circuit with a full-wave rectifier circuit. Which has the higher
output voltage? Which has the greater current in the diodes?
Full-wave rectifier needs a center-tapped transformer and a bridge rectifier does not.
The full wave rectifier has a higher voltage and the full-wave and bridge share the same
amount of current.
3. Why is it necessary to use two channels to view the entire secondary voltage?
You use two channels because neither side of the transformer is tied to ground.
4. How can you measure the ripple frequency to determine if a diode were open in a bridge
rectifier circuit?
The ripple frequency is normally twice the input frequency in a bridge rectifier. If one
diode were open, the ripple frequency would be the input frequency.
Conclusion:According to my partner’s results from Multisim, we both have different numbers
for the first two tables, but the third is very similar. This could be due to an error in calculating
the computed results.
My partner’s Table 3-1 & Table 3-2.