The sensor used in this circuit is uncommon today, however equivalent types can be tried. The comparator also supports modern equivalents. The circuit is from 80's documentation.
The circuit shown in the figure uses two of the four operational amplifiers found on the LM324...
Found in an Electronic Design, this small power source uses a battery as a voltage reference,...
This circuit was found in a 1969 US documentation. It provides a signal that can be externally...