Gummel plot

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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:[1]

  • 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.

SiGe HBT Gummel plot

See also[edit]


  1. ^ A. S. Zoolfakar et N. A. Shahrol, «Modelling of NPN Bipolar Junction Transistor Characteristics Using Gummel Plot Technique», in 2010 International Conference on Intelligent Systems, Modelling and Simulation (ISMS), 2010, p. 396–400.