This circuit is from Ferranti documentation from 1967. The operational is of the time, but the configuration is valid for modern equivalent components, including higher current capacity.
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...