A systematic method of linear small-signal V.H.F. analysis for valve circuits

While equivalent circuits of the valve with properties simulating electron inertia effects are known, the increased use of the V.H.F. band and the use of valve connections other than the once customary cathode-separation type has brought about the need for a simpler and more direct system of valve circuit analysis which ensures that electron inertia effects are inherent in the results. This paper outlines such a system of small-signal analysis. A basic functional circuit system of the triode is developed, in which the valve is regarded as a passive circuit element described by a set of linear equations expressing the mesh current associated with each adjacent pair of electrodes in terms of external small-signal voltages applied between a common point and each electrode. The general method of applying this basic system to any specific problem is to substitute an impedance (or a short-circuit) for one or more of the ideal external generators, in accordance with the substitution theorem of network analysis. The system is particularly applicable to the calculation of the noise factor of V.H.F. valve circuits Typical examples which illustrate the method of application are given.