This simple transistor tester was found in a Japanese magazine in 1967. It tests general purpose transistors of both the NPN and PNP type and is powered by 4 batteries (6 V).
This circuit was obtained in an English publication from 1978. It generates a ladder that goes up and...
This circuit was obtained in a 1964 magazine, but it can be easily assembled today, as the...
This circuit uses an optocoupler with a phototriac or optotriac to drive an external triac. The...