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 simple alarm circuit was found in a 1998 documentation. When the sensors are activated, the...
This circuit was found in an old American documentation. The integrated circuit used is uncommon...
Found in a 90s Electronic Design, this suggestion to have a higher voltage in a fixed regulator...