A method for analysis of direct-coupled transistor amplifiers

Graduation date: 1964The demand for transistor circuitry to perform within more\ud exacting specifications has created the need for a method to accurateIy predict transistor circuit performance. A method utilizing an\ud electronic digital computer for the analysis of direct-coupled transistor\ud amplifiers is explained in this paper.\ud The dc bias levels and the mid-band ac voltage amplification\ud of a circuit are discussed. The dependence of these parameters upon\ud changes in value of circuit components is investigated. The method\ud for analysis generated a mathematical model consisting of a system\ud of simultaneous equations for the physical model of the circuit.\ud From this system of equations the values of the node voltages and the\ud loop currents are found by solving these equations with a digital computer. The method of analysis provides a means to predict the circuit performance without physically constructing it. The predicted theoretical\ud values and experimental results showed good correspondence.\ud Where a digital computer is unavailable, the application of signal flow\ud graph techniques may be used as illustrated herein; however, the algebraic\ud manipulations may be awkward to handle