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.
We find this vibrato configuration with transistors in a 1987 documentation. The components are still...
This oscillator with the 4049 can generate signals up to about 14 MHz according to the article in the...
Found in a 90s Popular Electronics, this circuit provides sinusoidal signals at frequencies given by the...