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 a Popular Electronics from the 90s. The circuit uses a general purpose...
This 2000 circuit can work with one of the many infrared remote-control transmitters described in this...
We found this amplifier for automotive use in the Philips Databook of 1990. The circuit has a...