Found in Motorola documentation from the 1970s, the circuit presented uses a component from the era that is not common today. The characteristics of the coils are given next to the diagram.
We found this simple alarm circuit in a 1986 documentation. The circuit uses sensors of the NA...
This sound relay or Vox was found in 70s RCA documentation. SCRs can be common types today and...
Placed near a common receiver, this oscillator is intended to generate a beating signal to receive...