Under this name, Radioelectronics magazine published in the January 1974 issue a light exposure meter for photographers. The circuit used general-purpose transistors and a FET, with an LDR sensor.
This circuit is based on the light comparison of two LDR sensors. We found it in a 90s Popular...
This circuit was found in a 1975 documentation. Operational amplifiers must have a symmetrical source and...
This configuration can be applied to other transconductance operationals. The circuit has a gain...