RL Circuit Lab
Purpose: Today you are going to use the RCL circuit board. The inductor states that it has an 8.2 mH inductance. If you put the solid metal core into the inductor, will the inductance increase or decrease?
Procedure:
1. Connect the 750 to the computer with the USB cord. Connect the power cord and turn on the 750.
2. Plug a red cord into the output (sine wave below it) and bring the other end to the resistor of your choice.
3. Plug a black cord into ground (to the left of where you put the red cord) and bring the other end to the inductor. Verify that you have a complete circuit.
4. Plug a voltage sensor into channel A
5. Plug the other ends of the voltage sensor to each side of the inductor.
6. Double click on the “Data Studio” icon
7. Choose “Create an Experiment”
8. Click on Channel A. A pop-up menu will come up that allows you to choose “voltage sensor”.
9. Now click on the space that is in-between the two OUTPUT holes (remember where the sine wave and ground symbols were). Another pop-up window will appear that gives you the option for your signal generator. Choose “Square Wave”
10. Now choose “scope” from the display by double clicking on it. When it comes up with Channel A; click “OK”
11. Click the trigger switch and choose “rising level”
12. Hit start, and play around with the ms/div until you get a nice curve
13. Hit stop; then click on the “transfer data” button
14. Notice how it now has “data” listed in the data section
15. Now in displays, drag and drop “graph” onto your data so that you can better analyze your data.
16. Click on fit and choose “Natural Exponent Fit”
17. All you need to record is your value for “C”
18. Export your graph as a jpg file so that you can incorporate it into your lab write-up.
Analysis:
1. Starting from Maxwell’s version of Faraday’s Law, derive an equation for V(t).
2. Have your graph in the analysis section
3. From your “C” value of your lab, calculate the inductance of the metal core inductor.
4. Show that the time constant for a LR circuit has units of seconds.
Conclusions:
Discuss reasons for error and why your inductance was altered by the metal core and why it changed in the direction it did.