This circuit, found in a 1958 magazine, is for reference only, since the components are not easy to find today. The transistors are germanium types and power supply is made by common cells.
This wired intercom circuit was found in an English publication from the 80's. The integrated...
This triac temperature control circuit was found in an 80s power semiconductor documentation. The circuit...
This circuit is from 1998 documentation. The coils consist of the number of turns indicated on...