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.
Found in old documentation, this circuit uses components that are still common on the market. The...
This circuit activates a relay by activating one of a series of optical sensors that can be...
We found this circuit in a 1996 publication. Equivalent components can be tried, especially in the...