what is difference between voltage source and current source

Question

farcher · Answer

An ideal voltage source has zero internal resistance and a constant emf.  
An ideal current source has an infinite internal resistance and delivers a constant current..

In practice a voltage source has a finite internal resistance as does a current source.

anonymous · Answer

A voltage source is assumed to deliver energy with a specific terminal voltage which does not depend upon the current from the source, this is a constant voltage source.

A current source on the other hand is assumed to deliver current with a specified current through the terminals, this is a constant current source.

Well in the batteries the voltage ideally remains constant for a period of time, but the current can be different. To get constant current smart ics are invented.