Found in a 1968 EEE, this circuit accepts frequencies from 1 to 1000 Hz and control voltages from 0.1 to 15 V. The operational amplifier is from the era and can be replaced by modern equivalents.
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...