# Internal resistance of non ideal current and voltage sources

Why is real current source represented with resistor parallel with the source, while in the real voltage source resistor is in series with the generator? Can you give me an example for this situations?

• Think a bit for yourself. Would a resistor in series with a current source change the current to the load at all? Would a resistor in parallel to a voltage source affect the voltage on the load? The reason for those resistances is to model that the sources are not ideal. In an ideal voltage source, the series resistance is zero. In an ideal current source, the parallel resistance is infinite. In a real voltage source, part of the voltage is wasted in its series resistance. In a real current source, part of the current is wasted going thru its internal resistance. Commented Apr 3, 2016 at 16:21
• @ClaudioAviChami: You should post that as an answer.
– Rev
Commented Apr 3, 2016 at 17:19
• Related (not a duplicate): electronics.stackexchange.com/q/137020/17387 Commented Sep 13, 2017 at 5:36