Shot Noise in Transistors

The shot noise generated in a transistor may be represented in an equivalent circuit by a current generator ip across the collector junction and an emf es in series with the emitter junction. The characteristics of ip have been established by measurements of output equivalent saturated diode current made with the input open. The noise is independent of frequency up to approximately f¿¿1-¿0/L-l I-¿ o where¿fa is the a-cutoff frequency of the transistor. It increases sharply in the neighborhood of f¿, but then levels off at higher frequencies. The collector saturated current shows full shot effect up to frequencies well beyond the ¿-cutoff frequency. Information about es and about the correlation between es and ip has been obtained from measurements of the noise figure. At low frequencies (f<\n\n\t\t