This circuit was obtained in an Electronic Engineering of the 90s. The operational amplifiers and the sensor are from that time. The circuit has symmetrical power supply.
This circuit was found in a Electronics Handbook (1989). The shown amplifier provides a few...
The SCR used in this 80's circuit depends on the load. The control is half wave and instead of the neon...
This circuit was found in Delco documentation from 1966. The components are from that time....