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 1-transistor reflex receiver was found in a 1963 publication. The coil is for the mid wave...
This circuit was found in the National component manual which is not currently simple to obtain....
We found this cable tester in a Popular Electronics from the 90s. The circuit uses a connector...