MEASURING AC EMITTER AND BASE SERIES RESISTANCES IN BIPOLAR-TRANSISTORS

A convenient method for determining emitter and base resistances from small signal measurements has been developed. This method is based on Neugroschel's method, but the frequency has been varied instead of varying beta0. It is demonstrated that the base resistance was successfully extracted. The extracted emitter resistance depended on the collector current because of the difference between the exact g(m) value and the approximated one, I(C)/V(T). It has also been shown that the proposed method is more robust than the conventional impedance-circle method even when cross-talk ocuurs.