This circuit was obtained in a 1968 manual of General Electric. The components used are of the time, but they admit equivalent. Observe the optical feedback system for control.
This simple thermostat circuit was found in the September 1976 issue of Radio Electronics...
We found this circuit in the 1982 SGS Linear Integrated Circuits manual. The integrated circuit used...
This circuit uses a FET to drive an LED with constante currente. The current up to 20 mA can be...