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 1969 Philips documentation circuit makes it possible to control an engine through the sound...
We find this circuit in the manual of the used integrated circuits. The manual is from Linear...
This circuit can be used as a residential doorbell. We found it in an English publication from...