Properties of the super-alpha composite transistor at high frequencies

The equivalent circuit of the composite transistor, the input impedance and the current gain have been developed by analysing its equivalent circuit, in terms of the various parameters of the individual transistors in the common base and common emitter configuration. It is found that in the C.E. configuration, the short-circuit input impedance hi_e has a negative resistance component over a frequency range in which the current gain in the C.B. configuration h/b is greater than 1.