This CW circuit was found in a Radio Amateur Today from the 890s. The CMOS circuit must be powered by an isolated source and has different dash and dot timings.
This circuit was found in a 1986 publication. However, it can still be easily assembled, as the...
In the figure we have an anti-ring circuit with 4093. The duration of the pulse is given by R1 and...
This circuit was originally indicated to generate audio signal for analog TV sound. The circuit is from...