This triac circuit was found in the July 1995 Electronics Now magazine. The triac is based on the heating element current and must be equipped with a heat sink.
This circuit is from an English publication from 1976 but can be easily assembled with BC548...
This configuration, found in many publications, is from an American book from 1981. The power...
The purpose of this circuit is to ensure that an auxiliary 12 V battery continues to supply power...