Transcript Learning about AC signals

Learning about AC signals
ES 110
Basic Components
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Function generator
LED
Relay
Speaker
Pot
Ohm’s Law
Drawing the circuit
Schematic capture:
http://phet.colorado.edu/simulations/sims.php?sim=
Circuit_Construction_Kit_ACDC
Part I: Checking the function Generator
Connect the setup as shown
Change the frequency; what happens?
Make sure you can measure
the voltage and frequency
of the signal on the scope.
Take a snap shot of the
signal and save it in a file.
Part II: Tone Generator with Volume Control
Connect the setup as shown
Change the frequency; what do you hear as you change the
Pot value? What happens as you change the Frequency?
Show to your instructor what you observe.
Part III: LED Brightness Control
Connect the setup as shown – Use the 5V
Change the frequency; what happens to the LED as you change the
Pot value?
Draw the circuit on paper.
LED
Create a table with 3 columns:
Pot value, Voltage across the LED
And Color of the LED.
Record values for R=100, 1K, 2K, 5K ohms
NOTE: to measure the Pot you must disconnect all wires
Part IV: Blinking LED
Connect the setup as shown
Change the frequency; what happens? Draw the circuit on paper.
LED
Keep the POT=500 ohm.
Change the frequency. What happens?
Explain.
Submission (create a file and submit the
file. Don’t forget your names)
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Part I:
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Part II:
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Take a snapshot of the signal
On the signal show the frequency and voltage of the signal
What do you hear as you change the frequency?
Can you make a siren using two frequencies and a switch? Do this at the end.
What happens as you change the potentiometer? Explain why.
Part III:
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Create the table:
Resistor
V(LED)
V(POT)
V(Total)
100
1K
2K
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Part IV:
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5K
For what frequency ranges you can still see the LED blinking?
LED Brightness
Second Part
Part V: Checking the function Generator
Connect the setup as shown
Vpp=2V
T=1 msec
F=1KHz
This is the reference
Using Cursers on the Scope
Click on the Curser Button
Use Y to measure Vpp and X to measure the frequency.
This is one period
Using Multimeter to make AC and
DC measurements
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Watch this video and make sure you
understand it. Let me know if you have any
questions.
http://www.youtube.com/watch?v=iJxXjn2Gl
Ec
A- Make the following measurements:
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Adjust the generator so you see a 2V peak-to-peak square wave signal with
frequency of 8.5 KHz. DON’T forget UNITS!
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Take a snapshot of the signal (your snapshot must contain at least 2 cycles of the
signal)- Use the figure in the previous slide.
On you snapshot indicate how you measure Vpp, DC voltage (also called the offset),
and the period (as shown the previous slide). Watch the video for more information.
Use MSWord Equations to calculate the frequency of the signal from your plot. Show
all your work.
What is Vp of this signal?
Take another snapshot of the signal. This time make sure you set the voltage cursers
to show the Vpp.
Calculate the Vrms for this signal. Show your work using MSWord Equations.
Connect the signal to a multi-meter, and measure the frequency of the signal.
Connect the signal to a multi-meter, and measure the DC offset and V(AC) Can you
hear this signal?
B- Make the following measurements:
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Adjust the generator so you see a 12V peak-to-peak sine wave signal with
frequency of 750 Hz. DON’T forget UNITS!
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Take a snapshot of the signal (your snapshot must contain at least 2 cycles of the
signal)- Use the figure in the previous slide.
On you snapshot indicate how you measure Vpp, DC voltage (also called the offset),
and the period (as shown the previous slide). Watch the video for more information.
Use MSWord Equations to calculate the frequency of the signal from your plot. Show
all your work.
What is Vp of this signal?
Take another snapshot of the signal. This time make sure you set the voltage cursers
to show the Vpp.
Calculate the Vrms for this signal. Show your work using MSWord Equations.
Connect the signal to a multi-meter, and measure the frequency of the signal.
Connect the signal to a multi-meter, and measure the DC offset and V(AC) Can you
hear this signal?
Schematic Capture and Simulations
Go to
http://phet.colorado.edu/simulations/sims.php?sim=Circuit_Construction_Kit_ACDC and
build the circuit below. What happens when you change the value of the resistance?
More Information:
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Read about Voltage Dividers:
http://www.acroname.com/robotics/info/articles/interface/interface.html
A good tutorial on building a photoresistor circuit:
http://www.societyofrobots.com/schematics_photoresistor.shtml
Build a photoresistor circuit:
http://www.acroname.com/howto/photoresistor/photoresistor.html
Investigate photoresistors, infrared light emitting diodes (IRLED),
phototransistors, and fiber optic cable.
http://online.sfsu.edu/~larryk/engr206/Lab%20project%202.pdf
Other photoresistor related projects:
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Tone generator when the light dims
Light meter
How fast are you moving?
LED Brightness Control
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Go to
http://phet.colorado.edu/simulations/sims.php?sim=
Circuit_Construction_Kit_DC_Only
Build the circuit using POT=100 ohms and switch.
Take a snapshot and show it to the instructor. Use
schematic symbols – lifelike symbols.
Build the circuit using POT=1000 ohms and switch.
Take a snapshot and show it to the instructor.