This sound relay or Vox was found in 70s RCA documentation. SCRs can be common types today and transistor a BC558. The circuit is for the 110V power grid.
This circuit was found in documentation from the 80s. It is based on unijunction transistors not...
The speed of the motor connected to this circuit depends on the amount of light that strikes the...
This sensor circuit from a 1967 Ferranti documentation uses components from the era. The circuit...