Circuit Analysis Applied to the Screen-Grid Tube

General radio-frequency circuit theory is discussed in this paper. The theoretical work and discussion is divided into two parts, amplification and stability. General amplification equations for impedance and transformer coupling, using an untuned primary whose period is above the highest frequency considered, are derived and discussed for the case of a screen-grid tube such as Cunningham type CX-322. Feedback through the mutual capacity plate to grid capacity is also considered. A general expression for the limit of stable amplification per stage is inferred for n stages from the expressions found for one and two stages. This general expression Av. < V/ 2gm/ nwco is in terms of the mutual conductance, total grid to plate capacity, frequency and number of stages.