Novel methods for parameter extraction for bipolar transistors are presented. Emphasis is placed on reliable measurements of small-size transistors, examples are shown for Si integrated circuit transistors with emitters smaller than 10 mu m/sup 2/. Advantages over measurements on large-area test devices are discussed. Parameters measured are the current-dependent base and emitter series resistances, emitter contact resistance, base-emitter and base-collector space-charge region capacitances, junction temperature, and base and collector saturation currents. Applications to heterojunction bipolar transistors are demonstrated. >