Lab 7 (1)

docx

School

Capitol Technology University *

*We aren’t endorsed by this school

Course

100

Subject

Electrical Engineering

Date

Apr 3, 2024

Type

docx

Pages

Uploaded by UltraProton13572

Capacitor Charging and Discharging Lab 7 EL-100 Work done: 11/10/18 Date of Submission: 12/4/18 Christian Michael Allen Feldmann Purpose: In this lab, we used a simple circuit to charge and discharge capacitors to prove the charging equation v C = E(1 - e (-t / RC) ) and the discharging equation v C = V O * e (-t / RC) . We also used

this circuit to examine the directional change in current when charging and discharging the capacitor. Equipment and Materials: For this lab, we used the XK-150 digital trainer, the BK Test Bench 388A digital multimeter (DMM), various pieces of wire, two resistors with resistances of 100kΩ and 56kΩ, and a 220µF capacitor. Procedure: 1. Build circuit as shown in the diagram 2. Calculate the time constant for the circuit 3. Measure the time it takes for the capacitor to charge to the voltage value at 1 time constant, or 9.48V for the first circuit. 4. Compare the calculated and measured charge times. 5. Charge the capacitor completely. Note: if desired, a lower value resistor may be substituted here to decrease the charge time of the capacitor, since it is not being measured for this section. Be sure to swap back to the original resistor so you can measure the discharge time. 6. Measure the time required to discharge the circuit to the theoretical voltage it should read after 1 time constant of discharge, and compare it to the time constant. 7. Repeat the previous tests and calculations, now with a 56kΩ resistor instead of a 100kΩ resistor. Figure 1 The circuit used in charging position (changing the position of the switch would discharge the capacitor) Data & Calculations: τ computed Τ = R * C = 100kΩ * 220µF = 22s

τ measured (charging) From 0V to 9.48V: 22.52s τ measured (discharging) From 25V to 5.52V: 21.76s Table 1 Theoretical and measured values of τ with a 100kΩ resistor τ computed Τ = R * C = 56kΩ * 220µF = 12.32s τ measured (charging) From 0V to 9.48V: 12.82s τ measured (discharging) From 25V to 5.52V: 12.52s Table 2 Theoretical and measured values of τ with a 56kΩ resistor Conclusion: A: Questions 1Q) Describe how the results of Tests 1 and 2 confirm the theory. 1A) With both resistors, the amount of time it took to charge up to 63.2% of the final voltage or discharge to 36.8% of the final voltage was nearly equivalent to the theoretical value of τ, or R * C. 2Q) Move the switch to charge and note the sign of the multimeter reading. 2A) The sign was positive, therefore the current was flowing clockwise in the circuit. 3Q) Move the switch to discharge and again note the sign. 3A) The sign was negative, therefore the current was flowing counterclockwise in the current. B: Personal Conclusions C: Contributions Allen Feldmann- Purpose, Equipment and Materials, Data & Calculations, Conclusion Christian Michael- Procedure

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version