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 was found in an American documentation from the 80's. The components are from that...
The circuit shown is from the Texas Instruments optoelectronics manual. It is intended for audio...
This circuit drive an LED with constant current determined by the values of the resistors of 10...