Based on the CA3161 and CA3162, this circuit was found in the July 1990 Radio Electronics magazine. The circuit is two digits only.
This circuit for cars with mechanical ignition systems was found in the Electronics Experimenter handbook...
This code practice circuit was found in a 1990s issue of Radio Amaterur Today magazine. It...
The circuit presented was found in the Linear Applications Handbook of the National Semiconductoir of 1994....