Homework SourseInductor Properties and Functions iLab Steps Part I Basic In
Inductor Properties and Functions
iLab Steps
Part I: Basic Inductor Functions
Step 1: Open Circuit File
Open the circuit file Class Activity 1 Ind in the Week 1 folder found in Document Sharing utilizing MultiSim.
Step 2: Energize Circuit
Click the switch to turn on the circuit.
Step 3: Operation and Observation Procedure
Accomplish the following procedure to observe the operation of the circuit and to assist in the answering of questions at the end of the Part I.
1. Press the space key to energize the inductor and observe the effect for 30 seconds.
2. Press the space key to open the circuit.
3. Triple the supply voltage and repeat Steps 1 and 2.
Return the supply voltage to the original setting, double the inductance, and repeat Steps 1 and 2.
Step 4: Answer Questions
5. What happens to the inductor current as time passes?
6. What happened to the inductor current when the supply voltage was tripled?
7. What happened to the inductor current when the inductor value was doubled?
8. What would be the current if the inductor were allowed to energize indefinitely?
Part II: Basic Inductor Functions
Step 1: Open Circuit File
Open the circuit file Class Activity 2 Ind in the Week 1 folder found in Document Sharing utilizing MultiSim.
Step 2: Energize Circuit
Click the switch to turn on the circuit.
Step 3: Operation and Observation Procedure
Accomplish the following procedure to observe the operation of the circuit and to assist in the answering of questions at the end of the Part I.
1. Press the space key to energize the inductor. Once the current exceeds 1 amp, press the space key and observe the inductor voltage on the oscilloscope. Repeat several times.
2. Repeat Step 1, but allow the inductor current to exceed 5 amps.
3. Reduce the resistor value to 500 ohms and repeat Step 1.
Step 4: Answer Questions
1. What happened to the inductor voltage when the circuit was switched after exceeding 1 A?
2. Was the value negative or positive? Explain.
3. What was the peak inductor voltage? Explain.
4. What happened to the inductor voltage when the current exceeds 5 amps?
5. What happened to the inductor voltage when the resistor was reduced?
Part III: Resistors and Inductors in DC Circuits.
Step 1: Circuit Construction
Construct the circuit in Figure 1 with a 470 ohm resistor and a 10 mH inductor utilizing a 1 Vp square wave at 5 kHz as the source, in MultiSim.
Figure 1: RL Time Constant Circuit
Step 2: Calculation
Substitute the following RL combinations in the circuit and calculate the theoretical values of the time constants. .
a. 470 ohm, 10 mH
b. 220 ohm, 10 mH
Step 3: Operation and Observation Procedure
Connect channel A of the oscilloscope to the source and channel B to measure inductor voltage and measure the actual values from the original circuit configuration. Measure the inductor voltage for the times given in the table below for the energizing portion of the wave starting when the inductor begins to energize.
Table 1 Inductor Voltage vs. Time
Time (?s)
Measured (V)
Theoretical (V)
0
20
40
60
80
100
1. Calculate the theoretical inductor voltage values for the times in the table.
2. Reverse the position of the inductor and resistor in the circuit and measure the resistor voltage for the times given in the table below.
Table 2 Voltage vs. Time
Time (?s)
VR (V)
VL(V)
VT (V)
0
20
40
60
80
100
3. Copy the inductor voltages from Table 1 into Table 2.
4. Add the two voltages to obtain the total series voltage.
Step 4: Answer Questions
6. What was the theoretical and measured time constant?
7. What is a valid explanation for any differences observed?
8. What happens to the time constant when the resistance was decreased?
9. What would happen to the time constant if the inductance were decreased?
10. Where there any appreciable differences between the expected values and measured values?
11. Does the resistor voltage waveform appear correct for a series RL circuit?
12. Which law addresses the relationship of the series RL circuit?
| Time (?s) | Measured (V) | Theoretical (V) |
| 0 | ||
| 20 | ||
| 40 | ||
| 60 | ||
| 80 | ||
| 100 |
Solution
MULTIPLE QUESTIONS PLEASE SPLIT:
1) As the circuit is on the current throught the inductor increases. If the source is an DC source then ultimately the inductor acts a short circuit and the current = V/R.
2) When the switch is opened at first the inductor tries to oppose any change in the current through it, but eventually the current decreases to zero.
3) if the voltage source is tripled then the maximum current value is tripled but the rate remains the same as the charging and discharging of inductor cicuit depends on the resistance and the inductor.
4) doubling the inductor doubles the time constant and hence slower charging and discharging
