tell about common collector base amplifier and it's respective gains??

Question

i know about common base and emmiter but tell me weather using common collector is of any use??

Answer 1

One application for the common collector is to use it as a current source. Since the collector is a relatively high impedance source, it would work quite well in a constant current source for a fixed current to a load.

Answer 2

gain in terms of voltage is almost 1. Can be used as a bufer