SOURCE TRANSFORMATION AC CIRCUIT

SOURCE TRANSFORMATION

Source transformation in the frequency domain involves transforming a voltage source in series with an impedance to a current source in parallel with an impedance, or vice versa. As we go from one source type to another, we must keep the following relationship in mind:

Example:

Calculate Vx in the circuit using source transformation

First we transform the voltage source to a current source  where

Is=20angle-90/5

Is=4angle-90 or -j4A

The parallel combinations of 5ohms resistance and (3+j4) impedance gives

z1=5(3+j4)/8+j4

z1=2.5+j1.25ohms

We must convert the current source to a voltage source yields the circuit in the figure where

Vs=IsZ1=-j4(2.5+j1.25)=5-j10v

By voltage division,

Vx=(10/10+2.5+j1.25+4-j13)(5-j10)

Vx=5.519angle-28V