Vacuum-Tube Networks

The performance characteristics of vacuum-tube amplifiers are analyzed by combining the fundamental relations governing the motions of electrons within the vacuum tube with the methods of circuit-network theory. The result is an equivalent network based upon the electron-discharge stream rather than upon the external terminals of the tube. It is connected to the external terminals through simple impedance elements and allows the amplifier performance to be calculated in a comparatively straightforward manner even in the case of multielement tubes and when the electron transit time is not restricted to a small portion of the cycle. The phase delay in the transmission which results from electron transit time is calculated together with the input loading. This calculated loading must be increased to include the effects of Maxwellian distribution of electrons, which may be disregarded for a first approximation in many other applications. The analysis methods are applicable to velocity variation devices as well as to density variation or space-charge control and methods of handling such problems are briefly illustrated.