The circuit shown is from a 1994 National Semiconductor documentation and can be implemented with more modern operational amplifiers. The power supply must be symmetrical.
This circuit emits a sound when a magnetic field, of a magnet, for example, approaches the sensor....
Suggested by a 90's Linear Databook, this circuit compensates for capacitor hysteresis. The main...
This circuit was found in the Texas Instruments 1996 linear applications manual. It consists of a...