We found this circuit in an English publication from the 1980s. The circuit uses current components and can be tuned for frequencies between 300 and 1500 Hz.
This is the 4013 CMOS configuration as a flip-flop to divide the frequency of a rectangular signal...
This flasher was found in an 80's Electronic Engineering but can be easily implemented with modern...
We find this circuit in a 1995 documentation. It warns when the timing is nearing its end, with...