Non-ideal voltage and current source

[erece]

1. What is the difference between non-ideal voltage and non-ideal current source ( not in terms of circuit diagram like ideal voltage source plus series resistance )?

2. And how to decide that which source is used where and when ? ( because output of both is not constant)

 

[yungman]

Ideal voltage source has 0Ω output impedance so it can maintain the output voltage regardless of load. Ideal current source has infinite output impedance so it can drive the same current regardless of load and regardless of the output voltage.

So non ideal voltage source has non zero output impedance so the output voltage change with different load impedance. Non ideal current source has finite output impedance so the output current change when the output voltage is forced to change.

Which one to use depends on the application. One is a constant voltage, one is constant current regardless of load impedance!