for the common collector configuration shown i need to find the voltage gain. The voltage gain formula is AV = (β+1)(roll RE)/(rπ+(β+1)(roll RE) But in the circuit RE is absent . So how do we consider it ?? Nothing is given about the current source. from the circuit theory i know that the internal impedance of a current source is very high (am i correct ?). So in this case how do we relate it ?