NORTON THEOREM

Equivalent current INO is the current obtained at terminals A-B of the network with terminals A-B short circuited.

Equivalent resistance RNO is the resistance obtained at terminals A-B of the network with all its voltage sources short circuited and all its current sources open circuited.

or

Calculate the output voltage, VAB, when in open circuit condition (i.e., no load resistor — meaning infinite load resistance). RNO equals this VAB divided by INO.

way to simplified the complicated circuit with only dependent source and resistance into simple circuit by Norton theorem

Connect a constant current source at the output terminals of the circuit with a value of 1 Ampere and calculate the voltage at its terminals. This voltage divided by the 1 A current is the Norton impedance RNO. This method must be used if the circuit contains dependent sources, but it can be used in all cases even when there are no dependent sources.

way to simplified the complicated circuit with independent source and resistance into simple circuit by Norton theorem

**CHAPTER 4**

source transformation

voltage source in Thevenin theorem can be converted into current source in Norton theorem for making circuit more simple

RTH = RNO

VTH = INO*RNO, *=time

INO = VTH/RTH, /=divide

or

Thevenin teorem

superposition

The strategy used in the Superposition Theorem is to eliminate all but one source of power within a network at a time, using series/parallel analysis to determine voltage drops (and/or currents) within the modified network for each power source separately. Then, once voltage drops and/or currents have been determined for each power source working separately, the values are all “superimposed” on top of each other (added algebraically) to find the actual voltage drops/currents with all sources active. Let's look at our example circuit again and apply Superposition Theorem to it:

I=20/10 - 150/10 + 120/10 = -1A

Quite simple and elegant, don't you think? It must be noted, though, that the Superposition Theorem works only for circuits that are reducible to series/parallel combinations for each of the power sources at a time

Any linear electrical network with voltage and current sources and only resistances can be replaced at terminals A-B by an equivalent voltage source VTH in series connection with an equivalent resistance RTH.This equivalent voltage VTH is the voltage obtained at terminals A-B of the network with terminals A-B open circuited.This equivalent resistance RTH is the resistance obtained at terminals A-B of the network with all its independent current sources open circuited and all its independent voltage sources short circuited.

example 1

try it!

answer: RTH=1.153k ohms and VTH= 3.06V

example 2

example 3

example 4

**example 2**

**example 1**

**example 3**

example 4

**RN=3 OHMS, IN= 1A**

**TRY IT**