This circuit is from an1966 General Electric documentation. The Triac can be equivalent to 6 A or more, mounted on a good heatsink. Any diac can be used.
This circuit triggers in 100 microseconds in case of excess voltage. The adjustment is made in the...
This relay circuit with a dual channel MOSFET (not very common today) was found in an old American...
This circuit for audio signals was found in the March 1990 Radio Electronics magazine. The circuit...