## Superposition, Thevenin’s Norton’s circuit theorems

Almost all electric circuits are complex, but it is an engineer’s goal **to reduce their complexity to analyze them easily**. In this guide, we will introduce **new techniques** to strengthen our armoury to solve complicated networks. Also, these new techniques in many cases do provide **insight into the circuit’s operation** that cannot be obtained from mesh or nodal analysis.

Most often, we are interested only in the detailed performance of an

isolated portion of a complex circuit.

If we can model the remainder of the circuit with a simple equivalent network, then our task of analysis gets greatly reduced and simplified.

**to deliver maximum power to load**such as an audio speaker in a stereo system.

Here, we develop the required relationship betweeen a load resistor and a fixed series resistor which can represent the remaining portion of the circuit. Two of the three theorems that we present in this guide will permit us to do just that.

### Superposition theorem

The principle of superposition is applicable **only for linear systems**.

### Thevenin’s theorem

The main objective is **to reduce some portion of a circuit to an equivalent source and a single element**. This reduced equivalent circuit connected to the remaining part of the circuit will allow us to find the desired current or voltage. Thevenin’s theorem is based on circuit equivalence.

### Norton’s theorem

It states that a linear two-terminal network can be replaced **by an equivalent circuit consisting of a current source i _{N} in parallel with resistor R_{N}** , where i

_{N}is the short-circuit current through the terminals and R

_{N}is the input or equivalent resistance at the terminals when the independent sources are turned off.

If one does not wish to turn off the independent sources, then R_{N} is the ratio of open circuit voltage to short–circuit current at the terminal pair.

Title: | Circuit Theorems – Chapter 3 |

Format: | |

Size: | 3.20 MB |

Pages: | 118 |

Download: | Right here | Get Download Updates | Get Technical articles |

FAJERI

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