This electronic Morse Key for telegraph message transmission was found in an American 1980s amateur radio documentation. The circuit uses TTL technology and must be powered by a 5V voltage.
This experimental TTL circuit is from 1992 documentation. It produces programmed sounds set in the...
This simple receiver, which requires a good antenna and grounding, was found in an Argentine...
This circuit is from an old Signetics documentation. It can be implemented with modern operational...