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 was found in the Electronics Experimenter Handbook of 1961. The circuit uses door...
The basis of this circuit is a National Semiconductor operational amplifier that functions as a...
This two-transistor amplifier can be used as power stage for intercom, experimental receivers,...