This circuit was found in 1980s Radio Electronics. The circuit includes the power supply. The ICL8038 circuit was very common at the time in this type of application.
We found this circuit in a 1965 publication by General Electric. The zener is 8.2 V x 1 W and the...
This circuit was obtained in an Electronic Engineering of the 90s. The operational amplifiers and...
This circuit is suggested by Texas Instruments in his Optoelectronics Sourcebook. The transistors...