Charge-step-derived transfer functions for the junction transistor

The small-signal transient behavior of junction transistors may be considered to be dependent on two factors: the response to an instantaneously injected charge increment, and the relationship between excess minority-carrier charge and steady-state collector current. Simple approximations to the charge-step response waveform result in transfer functions which closely approximate that from the one-dimensional diffusion model. Certain types of experimentally observed nonideal behavior may be approximated by suitable choice of coefficients.