The measurement of transistor transient switching parameters

New parameters for use in the design of switching circuits are defined. These parameters relate the charge in the base region of the transistor to the terminal currents at given collector-base voltages. The relation of these parameters to small-signal parameters and rise-and-fall times is summarized, and methods of measurement using either normal small-signal techniques or transient techniques are described and discussed. The transient tests involve driving the transistor in the common-emitter configuration, through a parallel RC coupling circuit, by means of a square-wave generator. Under certain conditions the coupling capacitances and resistances yield values of the switching parameters.