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university:courses:electronics:electronics-lab-2 [05 Mar 2019 10:55] – [Activity 2i. Push - Pull Voltage Doubler] Antoniu Miclausuniversity:courses:electronics:electronics-lab-2 [23 Aug 2019 11:46] – amplitude peak-to-peak Pop Andreea
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-====== Activity 2. Diode I vs. V curves ======+====== ActivityDiode I vs. V curves ======
 ===== Objective: ===== ===== Objective: =====
 The purpose of this activity is to investigate the current vs. voltage characteristics of a PN junction diode. The purpose of this activity is to investigate the current vs. voltage characteristics of a PN junction diode.
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 ====Hardware Setup:==== ====Hardware Setup:====
-The waveform generator should be configured for a 100 Hz triangle wave with 6 volt amplitude and 0 volt offset. The differential input of scope channel 2 (2+,2-) is used to measure the current in the resistor (and diode). The Single ended input of scope channel 1 (1+) is used to measure the voltage across the diode (1- input can be grounded). The Scope should be setup with channel 1 at 500mV per division and channel 2 set also at 500mV per division. The current flowing through the diode, I<sub>D</sub>, is the voltage measured by channel 2 divided by the resistor value (1KΩ in this example). Use the XY display mode to plot the voltage across the diode (scope channel 1) on the X axis vs. the current in the diode (scope channel 2) on the Y axis.+The waveform generator should be configured for a 100 Hz triangle wave with 6 volt amplitude peak-to-peak and 0 volt offset. The differential input of scope channel 2 (2+,2-) is used to measure the current in the resistor (and diode). The Single ended input of scope channel 1 (1+) is used to measure the voltage across the diode (1- input can be grounded). The Scope should be setup with channel 1 at 500mV per division and channel 2 set also at 500mV per division. The current flowing through the diode, I<sub>D</sub>, is the voltage measured by channel 2 divided by the resistor value (1KΩ in this example). Use the XY display mode to plot the voltage across the diode (scope channel 1) on the X axis vs. the current in the diode (scope channel 2) on the Y axis.
  
 {{:university:courses:electronics:c_vs_v_diode-bb.png?600|}} {{:university:courses:electronics:c_vs_v_diode-bb.png?600|}}
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 ===== Hardware Setup: ===== ===== Hardware Setup: =====
  
-The waveform generator should be configured for a 100 Hz Sine wave with 6 volt amplitude and 0 volt offset. The scope channel 2 (2+) is used to measure the voltage across the load resistor, R<sub>L</sub>. Both scope channels should be set to 500mV per division.+The waveform generator should be configured for a 100 Hz Sine wave with 6 volt amplitude peak-to-peak and 0 volt offset. The scope channel 2 (2+) is used to measure the voltage across the load resistor, R<sub>L</sub>. Both scope channels should be set to 500mV per division.
  
 {{ :university:courses:electronics:half_wave-bb.png |}} {{ :university:courses:electronics:half_wave-bb.png |}}
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 ==== Further Exploration: ==== ==== Further Exploration: ====
  
-Replace the 1N914 diode with a light-emitting diode, or LED. You probably need to increase the AWG1 amplitude to 10V to accommodate the higher forward voltage drop of the LED.+Replace the 1N914 diode with a light-emitting diode, or LED. You probably need to increase the AWG1 amplitude to 10V peak-to-peak to accommodate the higher forward voltage drop of the LED.
 1. How does the waveform for the rectified output compare to your earlier results with the 1N914 diode? By how much does the forward-bias voltage drop increase? 1. How does the waveform for the rectified output compare to your earlier results with the 1N914 diode? By how much does the forward-bias voltage drop increase?
 2. Experiment with the three different waveform shapes while the waveform generator remains set to 100 Hz, pay attention to the brightness of the LED. Discuss your observations of waveform shape and brightness and relate these observations to your measured effective DC values for each waveform shape. 2. Experiment with the three different waveform shapes while the waveform generator remains set to 100 Hz, pay attention to the brightness of the LED. Discuss your observations of waveform shape and brightness and relate these observations to your measured effective DC values for each waveform shape.
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 ===== Hardware Setup: ===== ===== Hardware Setup: =====
  
-The first waveform generator, W1, should be configured for a 100 Hz Sine wave with 6 volt amplitude and 0 volt offset. The second AWG generator, W2, should be configured also for a 100 Hz Sine wave with 6 volt amplitude and 0 volt offset but with the phase set to 180 degrees. The Single ended input of scope channel 2 (2+) is used to measure the voltage across the load resistor. Both scope channels should be set to 500mV per division.+The first waveform generator, W1, should be configured for a 100 Hz Sine wave with 6 volt amplitude peak-to-peak and 0 volt offset. The second AWG generator, W2, should be configured also for a 100 Hz Sine wave with 6 volt peak-to-peak amplitude and 0 volt offset but with the phase set to 180 degrees. The Single ended input of scope channel 2 (2+) is used to measure the voltage across the load resistor. Both scope channels should be set to 500mV per division.
  
 {{ :university:courses:electronics:full_wave-bb.png |}} {{ :university:courses:electronics:full_wave-bb.png |}}
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 ==== Further exploration: ==== ==== Further exploration: ====
-Replace D<sub>1</sub> and D<sub>2</sub> with red and green LEDs. Increase the amplitude of AWG1 to 10V ( to accommodate the higher turn on voltage of the LEDs ). Slow the frequency of AWG1 to 5 Hz or less. Are the two LEDs ever both on at the same time? +Replace D<sub>1</sub> and D<sub>2</sub> with red and green LEDs. Increase the amplitude of AWG1 to 10V  peak-to-peak( to accommodate the higher turn on voltage of the LEDs ). Slow the frequency of AWG1 to 5 Hz or less. Are the two LEDs ever both on at the same time? 
 1. How does the waveform for the rectified output compare to your earlier results with the 1N914 diodes? By how much does the forward-bias voltage drop increase? 1. How does the waveform for the rectified output compare to your earlier results with the 1N914 diodes? By how much does the forward-bias voltage drop increase?
 2. Experiment with the three different waveform shapes while the waveform generator is set to 100 Hz, pay attention to the brightness of the LEDs. Discuss your observations of waveform shape and brightness and relate these observations to your measured effective DC values for each waveform shape. 2. Experiment with the three different waveform shapes while the waveform generator is set to 100 Hz, pay attention to the brightness of the LEDs. Discuss your observations of waveform shape and brightness and relate these observations to your measured effective DC values for each waveform shape.
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 ===== Hardware Setup: ===== ===== Hardware Setup: =====
  
-The waveform generator should be configured for a 100 Hz Sine wave with 6 volt amplitude and 0 volt offset. The scope channel 2 (2+. 2-) is used to measure the voltage across the load resistor, R<sub>L</sub>. Both scope channels should be set to 500mV per division.+The waveform generator should be configured for a 100 Hz Sine wave with 6 volt peak-to-peak amplitude and 0 volt offset. The scope channel 2 (2+. 2-) is used to measure the voltage across the load resistor, R<sub>L</sub>. Both scope channels should be set to 500mV per division.
  
 {{ :university:courses:electronics:bridge-bb.png |}} {{ :university:courses:electronics:bridge-bb.png |}}
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 ==== Further exploration: ==== ==== Further exploration: ====
  
-Replace all four diodes D<sub>1</sub>, D<sub>2</sub>, D<sub>3</sub> and D<sub>4</sub> with red and green LEDs. Increase the amplitude of AWG1 to 10V ( to accommodate the higher turn on voltage of the LEDs ). Slow the frequency of AWG1 to 5 Hz or less. Are two of LEDs ever both on at the same time? If so which two?+Replace all four diodes D<sub>1</sub>, D<sub>2</sub>, D<sub>3</sub> and D<sub>4</sub> with red and green LEDs. Increase the amplitude of AWG1 to 10V peak-to-peak ( to accommodate the higher turn on voltage of the LEDs ). Slow the frequency of AWG1 to 5 Hz or less. Are two of LEDs ever both on at the same time? If so which two?
 1. How does the waveform for the rectified output compare to your earlier results with the 1N914 diodes? By how much does the forward-bias voltage drop increase? 1. How does the waveform for the rectified output compare to your earlier results with the 1N914 diodes? By how much does the forward-bias voltage drop increase?
 2. Experiment with the three different waveform shapes while the waveform generator is set to 100 Hz, pay attention to the brightness of the LEDs. Discuss your observations of waveform shape and brightness and relate these observations to your measured effective DC values for each waveform shape. 2. Experiment with the three different waveform shapes while the waveform generator is set to 100 Hz, pay attention to the brightness of the LEDs. Discuss your observations of waveform shape and brightness and relate these observations to your measured effective DC values for each waveform shape.
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 ===== Hardware Setup: ===== ===== Hardware Setup: =====
  
-The first waveform generator should be configured for a 100 Hz Sine wave with 6 volt amplitude and 0 volt offset. The second waveform generator should be configured with 0 amplitude and 0 offset to start. The offset of the second generator will be varied and the effect on the output signal observed. Scope channel 2 (2+) is used to measure the clamped / limited voltage and should be set to 500mV/div. +The first waveform generator should be configured for a 100 Hz Sine wave with 6 volt peak-to-peak amplitude and 0 volt offset. The second waveform generator should be configured with 0 amplitude and 0 offset to start. The offset of the second generator will be varied and the effect on the output signal observed. Scope channel 2 (2+) is used to measure the clamped / limited voltage and should be set to 500mV/div. 
  
 {{ :university:courses:electronics:clamp-bb.png |}} {{ :university:courses:electronics:clamp-bb.png |}}
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 ===== Directions: ===== ===== Directions: =====
  
-Set up the breadboard with W1 attached to one end of the 1.0uF capacitor as shown in figure 16. The Diode (D<sub>1</sub>) is connected between the other end of the 1.0uF capacitor and the output of the second waveform generator, W2. Single ended input of scope channel 2 (2+) is connected to the common connection of the capacitor and the diode.+Set up the breadboard with W1 attached to one end of the 1.0uF capacitor as shown in figure 18. The Diode (D<sub>1</sub>) is connected between the other end of the 1.0uF capacitor and the output of the second waveform generator, W2. Single ended input of scope channel 2 (2+) is connected to the common connection of the capacitor and the diode.
  
 {{ :university:courses:electronics:a2_f6.png?600 |}} {{ :university:courses:electronics:a2_f6.png?600 |}}
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 ===== Hardware Setup: ===== ===== Hardware Setup: =====
  
-The first waveform generator should be configured for a 1KHz Sine wave with 2 volt amplitude and 0 volt offset to start. The offset will be varied and the effect on the output observed.  The second waveform generator should be configured with 0 amplitude and 0 offset to start. The offset will be varied and the effect on the output observed. Scope channel 2 (2+) is used to measure the voltage and should be set to 500mV/div.+The first waveform generator should be configured for a 1KHz Sine wave with 2 volt amplitude peak-to-peak and 0 volt offset to start. The offset will be varied and the effect on the output observed.  The second waveform generator should be configured with 0 amplitude and 0 offset to start. The offset will be varied and the effect on the output observed. Scope channel 2 (2+) is used to measure the voltage and should be set to 500mV/div.
  
 {{ :university:courses:electronics:DC_rest-bb.png |}} {{ :university:courses:electronics:DC_rest-bb.png |}}
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 <WRAP centeralign> Figure 20. DC Restoration waveforms </WRAP> <WRAP centeralign> Figure 20. DC Restoration waveforms </WRAP>
  
-Replace diode D<sub>1</sub> in the circuit with a 10K resistor. Using the measurement tab on the Scope, read and record the positive and negative peak values and mean value of channel2 (2+) as the offset of waveform generator channel 1 is changed between -1 and +1 volt. Now set waveform generator channel 1 to a square wave again with 2V amplitude value. As done before read and record the positive and negative peak values and the mean value as the duty cycle of the square wave is changed between 10% and 90%.+Replace diode D<sub>1</sub> in the circuit with a 10K resistor. Using the measurement tab on the Scope, read and record the positive and negative peak values and mean value of channel2 (2+) as the offset of waveform generator channel 1 is changed between -1 and +1 volt. Now set waveform generator channel 1 to a square wave again with 2V  peak-to-peak amplitude value. As done before read and record the positive and negative peak values and the mean value as the duty cycle of the square wave is changed between 10% and 90%.
 Now remove the 10KΩ resistor and put diode D<sub>1</sub> back in place. Repeat the same measurements, adjusting DC offset and duty cycle, that were just taken with resistor. How do they compare? Reverse the direction of diode D1 and again repeat these same measurements. How do they compare to the previous two?  Now remove the 10KΩ resistor and put diode D<sub>1</sub> back in place. Repeat the same measurements, adjusting DC offset and duty cycle, that were just taken with resistor. How do they compare? Reverse the direction of diode D1 and again repeat these same measurements. How do they compare to the previous two? 
      
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 ===== Directions: ===== ===== Directions: =====
  
-Set up the breadboard with the first waveform generator attached to one end of the 0.1uF capacitor as shown in figure 19. Resistor R<sub>1</sub> is connected between the second end of C<sub>1</sub> and junction of D<sub>1</sub>, R<sub>2</sub> and C<sub>2</sub>. The other end of D<sub>1</sub> is connected to ground. The second end of resistor R<sub>2</sub> is connected to the wiper of the potentiometer R<sub>3</sub>. The ends of R<sub>3</sub> are connected to ground and Vp (5V) respectively. Scope channel 2 (2+) is connected to the common connection of capacitor C<sub>2</sub> and load resistor R<sub>4</sub>.+Set up the breadboard with the first waveform generator attached to one end of the 0.1uF capacitor as shown in figure 21. Resistor R<sub>1</sub> is connected between the second end of C<sub>1</sub> and junction of D<sub>1</sub>, R<sub>2</sub> and C<sub>2</sub>. The other end of D<sub>1</sub> is connected to ground. The second end of resistor R<sub>2</sub> is connected to the wiper of the potentiometer R<sub>3</sub>. The ends of R<sub>3</sub> are connected to ground and Vp (5V) respectively. Scope channel 2 (2+) is connected to the common connection of capacitor C<sub>2</sub> and load resistor R<sub>4</sub>.
  
 {{ :university:courses:electronics:a2_f7.png?600 |}} {{ :university:courses:electronics:a2_f7.png?600 |}}
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 ===== Hardware Setup: ===== ===== Hardware Setup: =====
  
-Waveform generator W1 should be configured for a 10KHz Sine wave with 200 mV amplitude (or less) and offset set to 0. The set scope channel 1+ at 100mV per division and scope channel 2+ connected R4 at 100mV per division. Set the measurements tab to display Ch1 peak-peak and Ch2 peak-peak.+Waveform generator W1 should be configured for a 10KHz Sine wave with 200 mV peak-to-peak amplitude (or less) and offset set to 0. The set scope channel 1+ at 100mV per division and scope channel 2+ connected R4 at 100mV per division. Set the measurements tab to display Ch1 peak-peak and Ch2 peak-peak.
  
 {{ :university:courses:electronics:var_atten-bb.png |}} {{ :university:courses:electronics:var_atten-bb.png |}}
university/courses/electronics/electronics-lab-2.txt · Last modified: 03 Nov 2021 20:29 by Doug Mercer