We found this circuit in the 1983 edition of the Electronics Experimenter handbook. The circuit uses components that are common today, although many admit equivalents.
This circuit was published in a 1979 magazine, but it can still be easily assembled, as the...
This configuration found in GE documentation from the 90s, can also be seen elsewhere in this...
This simple circuit has good gain and can be implemented with any general-purpose transistor. The...