This 6-transistor commercial radio with 6 V supply was found in a Japanese publication from the 1960s. The circuit is a commercial superheterodyne with 150mW to 200mW of battery powered output.
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...