THE´ VENIN’S AND NORTON’S THEOREMS

THEVENIN’S AND NORTON’S THEOREMS

 

 

A linear, active, resistive network which contains one or more voltage or current sources can replaced by a single voltage source and a series resistance (The´venin’s theorem)or by a single currentsource and a parallel resistance (Norton’s theorem). The voltage is called the The´venin equivalentvoltage, V0, and the current the Norton equivalent current, I 0. The two resistances are the sameR0. When terminals ab in Fig.  are open-circuited, a voltage will appear between them

 

 

 

 

 

SUPERPOSITION

SUPERPOSITION

 

 

 

at super position method Voltage sources to be suppressed while a single source acts are replaced by short circuits; current sources are replaced by open circuits then we added the current in each branche at the two cases

EXAMPLE

Compute the current in the 23Ω resistor of Fig. by applying the superposition principle 

 

THE NODE VOLTAGE METHOD

THE NODE VOLTAGE METHOD

In the node voltage method, one of the principal nodes is selected as the referenceand equations based on KCL are written at the other principal nodes At each of these other principalnodes, a voltage is assigned, where it is understood that this is a voltage with respect to the referencenode. These voltages are the unknowns and, when determined by a suitable method, result in the network solution

[(V1 – 12)/3] + [(V1 -0)/6] + [(V1 –V2)/10] = 0

 

[(V2 – V1)/ 10 + [(V2 – 0)/12] -2 =0

 

then we can solve the two equation to get the value

of v1 and v2