This circuit uses an unusual sensor nowadays, but the configuration can be adapted to more modern types, as well as the operational amplifier. The circuit is from an 80's documentation.
This circuit came out in a publication called Electronics Handbook of 1993. The circuit shows how...
This is the conventional version of capacitance multiplier with operational amplifier that appears in...
) The integrated circuit used in this control is uncommon today and the maximum current obtained allows...