I'm confused between current and voltage sources; I get the text book definition but I am not able to understand real world difference. To me both current and voltage sources seem as the same. I understand that ideal sources doesn't exist. What is an example of practical current source? In order to produce current, we need voltage, so then isn't a current source also a voltage source? Since a battery is a voltage source and it produces current when connected to a circuit, isn't it also a current source?
Please help me understand real world example and usage of current source and how it is different from a voltage source.
Best Answer
A voltage source provides, as closely as it can manage to the ideal, a constant (or only slightly varying) voltage at whatever current is needed (in real supplies, to the limit of the current it can supply)
A current source provides, as closely as it can manage to the ideal, a constant (or only slightly varying) current at whatever voltage is needed (in real supplies, to the limit of the voltage it can supply.)
If you short-circuit a voltage source, you get extremely large currents (and normally blow a fuse/trip a breaker, etc.)
If you short-circuit a current source, you get the rated current at extremely low voltage, and nothing exciting happens.
If you open circuit a voltage source, it sits there at its rated voltage and does nothing interesting.
If you open circuit a current source, it shoots to its maximum voltage. If it was an ideal current source, it would drive itself to enough kilovolts to form an arc and get the rated current flowing in plasma. We don't really want ideal current sources in most situations for that reason.