The Common-Collector Transistor Amplifier at Carrier Frequencies

Expressions are derived for input resistance, output resistance and ratio of input to output voltage and current at low frequencies for transmission in both the base-to-emitter and the emitter-to-base directions. These expressions are extended to the carrier frequency range (up to approximately twice the alpha-cutoff frequency) by considering the effect of the variation of alpha with frequency, of collector capacitance and of load capacitance. Experimental evidence is presented which verifies the equations obtained.