This circuit is suggested by General Electric in 1966 documentation. The Triac must match the engine. The resistors depend on the triac's sensitivity to firing.
This 1965 General Electric circuit uses a "Thyrector" that is a suppressor of the time. The...
This circuit is from a 1992 publication, but can be mounted very easily today. The circuit is...
We found this circuit in the 1990 Motorola Linear Databook. The circuit must use symmetric source and has...