# Current source

electroboy12
hello.. this is my first post..forgive me if my question is wrong.. Why does a current source is modeled in such a way that it has its internal resistance in parallel ? Why can't it have its internal resistance in series ? The question may seem awkward , but please answer me.. thanks in advance..

## Answers and Replies

Gold Member
This may not be intuitive but Thevenin and Norton theorems tell you that any network of emf / current sources and resistances can be characterised by either an emf in series with or a current source in parallel with an appropriate resistance. That is not to say that it would be the best way to produce either, in practice! You could be making a lot of smoke if you chose the inappropriate one to use.

otto9K9otto
A current source is defined as, well, a source of current that has zero ohms source resistance. Electrically, this current source, when it is paralleled with a resistor, behaves identically to a voltage source that is in series with that same resistor. The amount of equivalent voltage is the product of the current (source) times the paralleled resistor.