Source Transformation Method in Circuit Analysis
Prepared by Engr. A.C.Patricio
Learning Objectives:
To be able to identify series or parallel resistance connected on a given source
To be able to simplify the number of meshes in the network.
To be able to solve circuit problems using source transformation method.
Source Transformation simply means replacing one source by an equivalent source. A
practical voltage source can be transformed into an equivalent practical current source and similarly
a practical current source into voltage source.
Voltage Source to Current Source Conversion
Assume a voltage source with terminal voltage V and the internal resistance r. This resistance is in
series. The current supplied by the source is equal to:
when the source of the terminals are shorted.
This current is supplied by the equivalent current source and the same resistance r will be connected
across the source. The voltage source to current source conversion is shown in the following figure.
Current Source to Voltage Source Conversion
Similarly, assume a current source with the value I and internal resistance r. Now according to the
Ohm’s law, the voltage across the source can be calculated as
Hence, voltage appearing, across the source, when terminals are open, is V.
