A Sixty-Cycle Bridge for the Study of Radio-Frequency Power Amplifiers

A selective bridge, consisting of three resistive arms and a fourth arm comprising a sinusoidal sixty-cycle voltage, has been devised and applied to the study of radio-frequency power amplifiers. In Part I the measuring circuits are described, and in Part II some typical data on a type 10 tube are presented. The observed linearity of contours of constant plate loss on a diagram plotted to the coördinates of output carrier-frequency voltage and plate-battery voltage is discussed, and a very simple circuit, based on this result and useful for rough measurements, is described.