We found this circuit in the April 1996 issue of Electronics Now magazine. The circuit uses a symmetrical source and is part of an instrumentation project.
Originally, this 2000 documentation circuit was created to operate as a sensor for the parallel...
For those who have multimeters that do not test transistors, in the figure we have a circuit that...
Used with infrared remotes at the time, this circuit was found in a 1991 RE Experimenter Handbook....