Noise in diffused transistors

Extensive measurements of noise figure have been made on diffused silicon and diffused germanium transistors intended for use as high-frequency amplifiers. The measurements serve the twofold purpose of providing an adequate characterization of the devices for circuit designers and of permitting a comparison to be made with existing theory. Although data have been obtained at suitably spaced frequencies extending from 1 kc to 150 mc, emphasis will be placed on shot noise rather than on the excess noise component which is significant only at frequencies below 1 mc. The dependence of the noise figure on source resistance, current and frequency will be discussed from the point of view of obtaining optimum circuit performance.