DC current source
A current source with infinite internal impedance is considered to be an ideal or constant current source. An ideal current source supplies a constant current to a load even if its impedance changes.
An ideal current source does not exist because any source cannot supply constant current even if its terminals are open-circuited.
A current source with infinite internal impedance is considered to be an ideal or constant current source. An ideal current source supplies a constant current to a load even if its impedance changes.
An ideal current source does not exist because any source cannot supply constant current even if its terminals are open-circuited.
Practical DC current source
Practically the current sources don’t have infinite resistance across them but has some finite and high resistance. Due to the finite resistance the practical current source shows some dependency on the voltage across it. So the current delivered by a practical current.
The current to delivered to the external circuit It is given by,
It=Is-(V/R)
It=Is-(V/R)
V-I characteristics
The below figure shows the V-I characteristics of a practical current source along with its comparison with the characteristic of ideal current source. The reduction of the current is due the internal resistance R.
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