Question

Define Ideal constant voltage source.

Answer 1

It is that that voltage source whose internal resistance is infinite. Here, source possesses very high resistance as compared to that of external load.

6 V battery has an internal resistance of 1 MΩ and load resistance varies between 20 KΩ to 200 KΩ. So, current supplied by the source varies from 6/1.02 = 5.9 μA to 6/1.2 = 5 μA. So, it is seen that even when load resistance increases 10 times, current decreases by 0.9 μA.

Hence source can be considered constant current source.

Answer 2

A constant voltage source is a power source which provides a constant voltage to a load, even despite changes and variance in load resistance. In other words, the voltage which a constant voltage source provides is steady, even if the resistance of the load varies