This transistor tester with different gain ranges was found in documentation from the 1980s. The circuit can still be implemented with more modern components and used with general purpose transistors.
This application is from a circuit manual from the 90s and only works with incandescent lamps. The triac...
This circuit was found in an American magazine in 1978. It activates a relay when the speed of a...
This circuit is from 1976 documentation, but it can be assembled with more modern transistors like...