In electronics, the Gummel plot is the combined plot of the base and collector electric currents, I c and I b , of a bipolar transistor vs. the base-emitter voltage, V b e , on a semi-logarithmic scale. This plot is very useful in device characterization because it reflects on the quality of the emitter-base junction while the base-collector bias, V b c , is kept at a constant.
A number of other device parameters can be garnered either quantitatively or qualitatively directly from the Gummel plot:
the common-emitter current gain, β , and the common-base current gain, α base and collector ideality factors, n series resistances and leakage currents.Sometimes the DC current gain, β , is plotted on the same figure as well.
