On the Application of Thévenin Equivalent Circuits to the Analysis of Vacuum Tube Circuits

Abstract

In this paper, we express Thévenin equivalent circuits seen looking into the terminals of the small-signal model of the vacuum tube triode in terms of the Thévenin equivalent circuits seen looking out of the other terminals and apply them to the analysis of the common-cathode, common-plate, and common-grid single-tube amplifier configurations, as well as a differential pair amplifier. This is an adaptation of equivalent circuit techniques for transistor circuits pioneered by Marshall Leach. The use of equivalent circuits can yield intuitive solutions that avoid solving sets of equations.