ECEN 214516
PostLab 3
Equivalent Networks and Superposition
Procedure
Task 1: Verify Thévenin's equivalent
 First we constructed the circuit in Figure 3.4 of the lab manual.
Figure 3.4: Task 1 Circuit
 For the power source instead of the batteries we used the voltage source on the PMD to generate a constant 3V power source.
 We measured the source first to make our calculations more accurate later.
 Next, we used the voltmeter to measure the voltage across the load resistor of
 Then, we tested the same voltage after trying a 470 resistor and then keeping the circuit open.
Task 2: Verify the superposition principle
 First we constructed the circuit in Figure 3.5 of the lab manual.
Figure 3.5: Task 2 Circuit
 For the power sources we used both wave generator power sources on the PMD, to generate the constant 3V and 4V.
 We then measured the sources for better calculation accuracy.
 Then, we measured the voltage accros the 1kΩ resistor with both power sources active.
 Next, we tested the same voltage but withopen, them again with open.
Task 3: Check the superposition principle validity for a nonlinear device
 First, we constructed the circuit in Figure 3.6 of the lab manual.
Figure 3.6: Task 3 Circuit
 For the rest of Task 3, we followed the same steps as Task 2. The key difference between Task 2 and 3 is that there is a diode between the 1kΩ and the 5.1kΩ resistors as shown in Figure 3.6.
Data Tables with Results
Task 1: Verify Thévenin's equivalent
 Power Supply Voltage: 2.993 V
Table 1: Load Voltage and Load Resistance
2180 Ω 
2000 Ω 
0.764 V 
1.597 V 
2180 Ω 
470 Ω 
0.280 V 
1.570 V 
2180 Ω 
Open Circuit 
1.605 V 
1.605 V 
Task 2: Verify the superposition principle
 Power Supply : 2.992 V
 Power Supply : 3.992 V
Table 2: Load Voltage Given Different Power Sources
Parameter 
Measured 
Calculated 
% difference 
SPICE 
% difference (SPICE to measured) 
3.992 V 
4 V 
0.200 
4 V 
0 

2.992 V 
3 V 
0.267 
3 V 
0 

0.283 V 
0.291 V 
2.75 
0.291 V 
2.75 

0.570 V 
0.556 V 
2.52 
0.556 V 
2.52 

0.280 V 
0.265 V 
5.66 
0.265 V 
5.66 
Task 3: Check the superposition principle validity for a nonlinear device
 Power Supply : 2.992 V
 Power Supply : 3.992 V
Table 3: Load Voltage Given Different Power Sources (with diode)
Parameter 
Measured 
Calculated 
SPICE 
% Error 
3.992 V 
4 V 
4 V 

2.992 V 
3 V 
3 V 

0.897 V 
0.15 V 

0.830 V 
2.255x10^9 V 

1.11 V 
1.125x10^9 V 
Equations and Calculations
Task 1: Verify Thévenin's equivalent
Task 2: Verify the superposition principle
Task 3: Check the superposition principle validity for a nonlinear device
Discussion:
Task 1: Verify Thévenin's equivalent
In, the prelab for task 1 we found that the theoretical was approximately 1.61 V. This was then proved while performing task 1 in the lab. For each circuit was extremely close to 1.61 V. There is error with our measurements, due to a variety of different factors. One factor is that everything has resistance, including wires, so there can be loss in electricity to different things that should not really be part of the system in an ideal world.
Task 2 and 3: Verify the superposition principle
In task three, superposition will not work simply because the diode will stop electrons from flowing in different directions. The diode forces everything to go in the same direction and so no voltages can cancel others out.
Conclusion:
Over all, I found this lab interesting. I think that it could be useful to use the Thevenin equivalent technique in the real world in order to simplify a problem and make it easier to understand. I think this definitely has real world applications and I am glad we learned more about it in lab. I look forward to learning about more electrical engineering topics as the semester progresses.
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