This circuit for cars with mechanical ignition systems was found in the Electronics Experimenter handbook from 1991. It inhibits the ignition system, preventing theft.
This conventional series reducer circuit reduces the voltage of a 12 V battery to the selected value...
In the figure we have a converter that generates a negative voltage from a positive voltage...
This circuit covers the bands from 1.8 to 150 MHz, with plug-in coils whose characteristics are...