# CHAPTER 5

*Circuit Theorems*

**IN THIS CHAPTER**

**5.1** Introduction

**5.2** Source Transformations

**5.3** Superposition

**5.4** Thévenin's Theorem

**5.5** Norton's Equivalent Circuit

**5.6** Maximum Power Transfer

**5.7** Using MATLAB to Determine the Thévenin Equivalent Circuit

**5.8** Using PSpice to Determine the Thévenin Equivalent Circuit

**5.9** How Can We Check … ?

**5.10 DESIGN EXAMPLE**—Strain Gauge Bridge

**5.11** Summary

Problems

PSpice Problems

Design Problems

## 5.1 *Introduction*

In this chapter, we consider five circuit theorems:

- A
**source transformation** allows us to replace a voltage source and series resistor by a current source and parallel resistor. Doing so does not change the element current or voltage of any other element of the circuit.
**Superposition** says that the response of a linear circuit to several inputs working together is equal to the sum of the responses to each of the inputs working separately.
**Thévenin's theorem** allows us to replace part of a circuit by a voltage source and series resistor. Doing so does not change the element current or voltage of any element in the rest of the circuit.
**Norton's theorem** allows us to replace part of a circuit by a current source and parallel resistor. Doing so does not change the element current or voltage of any element in the rest of the circuit.
- The
**maximum power transfer theorem** describes the condition under which one circuit transfers as much power as possible ...