A General Junction-Transistor Equivalent Circuit for Use in Large-Signal Switching Analysis

This paper describes a general medium-speed junction-transistor equivalent circuit that is valid for large- and small-signal operation. Solutions of nonlinear differential equations written from the equivalent circuit for its response to large-signal driving pulses are obtained by graphical, analytic, and analog computer techniques. The static base-to-emitter V-I characteristic is used extensively in the various analysis techniques and produces the proper response to a driving source of any internal resistance. In Section II a charge-control equation is employed for constructing the equivalent circuit in a common-emitter hybrid π configuration. Section III deals with the techniques for solving large-signal switching problems. Section IV discusses some of the required measurements.