This circuit found in the February 1992 issue of Radio Electronics magazine is designed to adapt an audio signal for use in a computer's ADC. It can be adapted to operate with microcontrollers.
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....