Found in an Electronic Design of 1964, this circuit is intended to the signal amplification in the 88 to 108 MHz band. The transistor can be a modern equivalent.
Using SCRs, this circuit from a 1967 General Electric manual allows full wave load control with SCRs....
This interesting circuit from a publication from the 1970s, measures the intensity of the sound...
This simple NPN and PNP transistor tester configuration can use the low current range of a common...