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 well-crafted speed game setup for two competitors was found in a 1998 Poptronics. The circuit...
I found this electronic organ in magazine published in 1976 from my vast collection of foreign...
This circuit was found in an application note of the LTC1164 from Linear Technology of the 1990s....