I give several simple examples of model Langmuir probe current-voltage I-V characteristics that
help students learn how to interpret real I-V characteristics obtained in a plasma. Students can also
create their own Langmuir probe I-V characteristics using a program with the plasma density,
plasma potential, electron temperature, ion temperature, and probe area as input parameters. Some
examples of Langmuir probe I-V characteristics obtained in laboratory plasmas are presented and
analyzed. A few comments are made advocating the inclusion of plasma experiments in the
advanced undergraduate laboratory.