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 egg timer has been found in an English magazine that no longer exists in 1982. The...
This circuit was obtained in the publication 101 Electronics Projects of 1979. The circuit can be...
Found in Popular Electronics from the 1980s, this circuit uses two operational amplifiers from...