This 1.5W tube amplifier was found in an American documentation from 1947. It is a direct rectification circuit without the need for a power transformer.
This interesting automotive alarm was found in a 90's Popular Electronics. The circuit uses...
Using the 4001 integrated circuit, this latching relay can employ any general-purpose transistor. The...
The PA222 integrated circuit used in this project from an American 1967 documentation is not...