ENGR336 Lab 2022 Fall
Lab 1: Review Superposition, Thevenin's Equivalent Circuit, and LTSpice
Name: Seth VanMatre
Email: sgvanmatre@fortlewis.edu

Review Superposition, Thevenin's Equivalents, and LTSpice

Introduction
The objective of this lab is to review Superposition, Thevenin's Equivalent Circuit, and being able to simulate the theoritical circuit in LTSpice. Both of these circuit techniques are derived from applying the simple principle of Ohms Laws, Kirchhoff's Voltage Law, and Kirchhoff's Current Law.       

Materials and Methods
Task 1
Apply SuperPosition Theorm on the circuit in 'Task 1' to find all the voltages and current throughout the circuit. Then without the use of symbols/schematics simulate the circuit in LTSpice only using Spice code.

Task 2
Apply Thevenin's Equivalent Circuit to the circuit in 'Task 2'. Use the 4nF capacitor as the load for this circuit to find Rth and Vth. Once the equivalent circuit is calculated use LTSpice, only using Spice code, to simulate the circuit. 

Results
Task 1
Figure 1 shows the hand calculation for 'Task 1' applying Superposition to solve for all the voltages and currents throughout the circuit. These values can be seen in Table 1.  Figure 2 represents the simulation of  the circuit in LTSpice. The currents and voltages going through each resistor can be seen- blue line is the current and the green line is the voltage.  

CalcWork
 Figure 1: Calculations for Superposition Theorm.


VR1 = .3vVR2 = .3vVR3 =.3v
IR1 = .2mAIR2 = .2mAIR3 =.4mA
Table 1: Voltages and currents across 'Task 1' circuit.


R1
Figure 2a: Voltage and current across R1.

R2
Figure 1b: Voltage and current across R2.

R3
Figure 2c: Voltage and current across R3.


Task 2
The calculations for Thevenin's Equivalent Circuit can be seen in Figure 3. The values for VTH and RTH were calculated out to be 1.6v and 2k ohms. Figure 4 shows the simulation of the Thevenin's Equivalent Circuit using the 'PULSE' function to charge up the capacitor.


Work2
Figure 3: Calculation for Thevenin's Equivalent Circuit for "Task 2'.



Task2s
Figure 4: Simulation of the calculated Thevenin's Equivalent Circuit.



Discussion
Reviewing how to do Superposition Theorm, Thevenin's Equivalent Circuit, and LTSpice has helped me not only in this class but also in Anolog. The theoritical calculations matched up exactly to what was being measured using LTSpice.