The integrated circuit used in this application is uncommon today. The circuit converts capacitances into voltages from 1 to 10 V for a capacitance range from 10 uF to 100 uF.
This circuit was obtained in the Linear Applications Handbook of the National Semiconductor of...
We find this circuit in an old technical documentation. The circuit can be drawn up with other...
Using a 555, this configuration appears elsewhere on this site. This is from American...