CE 338 2021 Spring

Lab 1: Superposition and Thevenin's Review

Nic Theobald

nstheobald@fortlewis.edu

Superposition and Thevenin's Review

### Introduction

This
lab is a review of two circuit analysis methods, Superposition and
Thevenin's equivalent circuits. Superposition is useful for when there
are multiple voltage sources that can be turned on or off. Thevenin is
useful for when a simplified version of the circuit is needed for
further analysis.

## Methods and Materials

Superposition is the method of solving a circuit while
considering the affects of one voltage source at a time. The circuit in
Figure 1 was solved by
considering V1 and V2 independently. V2 was shorted and the voltages at
each node were calculated, as well as the current through each
resistor. The same voltages and currents were then calculated when
V1 was shorted. The voltages and currents were then summed to find the
resulting voltages and currents. The second example first found the
thevenin equyivalent of the original circuit. The thevenin equivalent
was then used to find a reasonable on/off tme for the RC circuit.

## Results

Task 1: Superposition Review

Figure 1: Original Circuit

First, the circuit was solved when V2 was shorted.

Then the circuit was solved when V1 was shorted.

Currents and Voltages were then summed.

s

The circuit was then simulated in LTspice.

Task 2: Thevenin Equivalent

First, V1 was shorted and Rth was found.

Then Eth was found.

Then the circuit was simulated.

### Discussion:

This lab reviewed Superposition and Thevenin equivalent crcuits.
The first example was a simple circuit easily solved by superposition.
The second example required the circuits Thevenin equivalent to
determine a reasonable pulse on/off time.