Running Head: Half Wave Rectifier 1

Rectifier Fundamentals

Half Wave Rectifier

In this lab you will build circuits used to convert alternating current to pulsating direct current using semiconductor diodes.

In this section we will look at a simple half wave rectifier circuit.

Niagara College Photonics Engineering Technology

No sector of business or industry remains untouched by photonics, the science of generating and harnessing light. The Photonics Engineering Technology program at Niagara College encompasses optics, lasers, electro-optics, spectroscopy and electronics technology.

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Document content developed by:

Alexander McGlashan

Niagara College of Applied Arts and Technology

School of Technology, Department of Photonics

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Purpose

In this section we will look at a simple half wave rectifier circuit used to convert alternating current to pulsating direct current.

myDAQ Half Wave Rectifier using an LED

Parts Required:1 – 1.5kΩ resistor1 – Red LED

1. Construct the following circuit

2. Launch the function generator from multisim or the NI ELVISmx Instrument Launcher. Set the frequency to 200mHz Set the amplitude to 10Vpp Select the Sine waveform

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3. Click run and observe the action of the LED.

4. Based on your observations of the LED and the knowledge that the source voltage is a 10Vpp sine wave, describe what you think is occurring to the current through the LED during one complete cycle of the source waveform.

Multisim Simulation and myDAQ

1. Open the Multisim file Half Wave Rectifier.ms12

2. In the simulation, wire inputs AI 0 across output AO 0 (measuring our source voltage with Channel 0) and AI 1 across the load resistor (measuring the load voltage with Channel 1, which will also be proportional to the current through the circuit).

3. Open the function generator and oscilloscope. Set the frequency to 60Hz Set the amplitude to 10Vpp Select the Sine waveform

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4. Run the simulation and adjust the scope settings such that one cycle of the source is clearly visible.

5. Since the voltage displayed on Channel 1is directly proportional to the current in the circuit, we can see that current is only flowing during one half cycle of the source waveform.

Measure and compare the frequency of Channel 0 and Channel 1 Measure the peak voltage of Channel 0 Measure the peak voltage of Channel 1 What is the peak voltage drop across the Light Emitting Diode?

6. On the real myDAQ, wire inputs AI 0 across output AO 0 and AI 1 across the load resistor as you did in the simulation.

7. In the Instrument Control for your generator and scope, make sure to set them both to the real myDAQ device (not the simulation).

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8. Run the instruments and compare the real and simulated results.

9. Reverse the LED in your circuit so it is facing in the opposite direction and rerun the circuit.

How is the load voltage and current in the circuit affected? Why does this happen?

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Multisim Simulation and myDAQ Half Wave Rectifier using a Rectifier Diode

Parts Required:1 – 1.5kΩ resistor1 – 2.2kΩ resistor1 – 1N400x rectifier diode

1. Replace the LED in your simulation with a 1N4001 rectifier diode

2. Open the function generator and oscilloscope. Set the frequency to 60Hz Set the amplitude to 10Vpp Select the Sine waveform Run the simulation

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3. Note the difference between the load voltage in this circuit (using a rectifier diode) and that of the previous circuit (using an LED).

Measure and compare the frequency of Channel 0 and Channel 1 Measure the peak voltage of Channel 0 Measure the peak voltage of Channel 1 What is the peak voltage drop across the diode? Based on these results, which device is more efficient at rectifying the signal?

4. In the real circuit, replace the LED with a 1N400x rectifier diode and run the circuit.

5. What accounts for the difference in real and simulated values? Measure the peak voltage across the load and calculate the peak current.

Compare this value to the maximum current that the AO output is capable of sourcing (check the myDAQ specifications).

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6. Replace the 1.5 kΩ load resistor with a 2.2 kΩ resistor and rerun the experiment Measure and compare the frequency of Channel 0 and Channel 1 Measure the peak voltage of Channel 0 Measure the peak voltage of Channel 1 What is the peak voltage drop across the diode? Calculate the load current.

7. Using the scope Log function (located in lower right corner of the scope instrument panel) save your data and then import it into a spreadsheet program.

Create a data series calculating the Load Current Plot Channel 0 (Source Voltage) Plot Channel 1 (Load Voltage) Plot Load Current (use a secondary y-axis scale) Label all elements