Learning about AC signals ES 110 Basic Components

Learning about AC signals ES 110

Basic Components o o o o 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 5 V 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, 1 K, 2 K, 5 K 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) n Part I: o o n Part II: o n 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: o Create the table: Resistor V(LED) V(POT) V(Total) 100 1 K 2 K n Part IV: o 5 K 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=2 V T=1 msec F=1 KHz 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 o Watch this video and make sure you understand it. Let me know if you have any questions. http: //www. youtube. com/watch? v=i. Jx. Xjn 2 Gl Ec

A- Make the following measurements: o Adjust the generator so you see a 2 V peak-to-peak square wave signal with frequency of 8. 5 KHz. DON’T forget UNITS! n n n n 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: o Adjust the generator so you see a 12 V peak-to-peak sine wave signal with frequency of 750 Hz. DON’T forget UNITS! n n n n 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: o o o Read about Voltage Dividers: http: //www. acroname. com/robotics/info/articles/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. html Investigate photoresistors, infrared light emitting diodes (IRLED), phototransistors, and fiber optic cable. http: //online. sfsu. edu/~larryk/engr 206/Lab%20 project%202. pdf Other photoresistor related projects: n n n Tone generator when the light dims Light meter How fast are you moving?

LED Brightness Control o o o 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.