Two-Terminal Analysis and Synthesis of Junction Transistor Multivibrators

The basic junction-transistor multivibrator circuit is analyzed from the point of view of a circuit designer who Wishes to know: (a) how to predict the performance of a particular configuration, and (b) how to synthesize a multivibrator circuit, which may be either astable, bistable, or monostable, from a given set of specifications. The analytical method consists of breaking the multivibrator circuit (two basic, well-known configurations are treated) at a suitable point and using, the two terminals thus obtained as a driving-point pair to derive a useful V-I characteristic. In part I of the paper, the static driving-point resistance characteristics arc derived theoretically and compared to experimental measurements. In part II, transient and high-frequency effects are considered and the two-terminal analysis is extended to derive a prediction of the maximum frequency, or pulse repetition rate, at which the regenerative mode of operation can take place. Part III of the paper treats the problem of circuit synthesis. Using the results of parts I and II, straightforward methods are developed which permit the circuit designer to uniquely determine the seven circuit parameters which must be specified in the design of symmetrical multivibrators. Several design examples of astable, monostable, and bistable configurations are given.