Gummel plot
In electronics, the Gummel plot is the combined plot of the base and collector electric currents,  and , of a bipolar transistor vs. the base–emitter voltage, , 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, , is kept constant.

A number of other device parameters can be garnered either quantitatively or qualitatively directly from the Gummel plot:
 The common-emitter current gain, , and the common-base current gain, ,
 Base and collector ideality factors, ,
 Series resistances and leakage currents.
Sometimes the DC current gain, , is plotted on the same figure as well.

See also
 Hermann Gummel
 Bipolar junction transistor
 Gummel–Poon model

References

Transistors
Plots (graphics)