This 80's Exar circuit has a carrier detector for frequencies up to 500 kHz. The circuit uses a company 567 which is still a common component.
This dual-LED circuit indicates three signal levels. It was found in the January 1996 issue of...
This circuit was obtained in a 90s Electronic Design. The circuit uses components from that time....
We found this circuit in Linear Technology Applications 1993. The maximum output current is 5 A...