The reference voltage for this circuit can be selected digitally. The circuit is from Radio Electronics dated February 1981. The 741 must be powered by a symmetrical source.
This circuit compensates for the brightness of an LED as a function of temperature. We found it in...
This very sensitive circuit works almost like an electroscope. The FET can be the BF245 and it...
Constant currents from 10 mA to 1 A can supply the load, depending on the selection made by S1. Q1...