This circuit was found in a Hands On Electronics from the 90s. The circuit does not need a symmetrical power source. The signals with which it operates are alternating.
This circuit was found in an old 1970s telecommunication documentation. It is suitable for...
Suggested by General Electric in a 1967 publication, this circuit makes use of an SCR of the time....
This circuit allows selective relay actuation in the same line according to the applied voltage....