This circuit was obtained from a 1967 GE SCR manual. The SCRs must be rated for the wattage of the controlled heating element.
This circuit with the 741 operational amplifier was found in the March 1995 issue of Electronics Now...
This circuit was found in a General Electric documentation from 1966. It uses discrete components...
We found this circuit in a French technical documentation from 1982. The circuit can be...