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 circuit, found in a 1980 publication, limits the amplitude of the output signal to a value...
This VFO was found in a 1980s documentation. The central frequency is given by the crystal and the...
This traditional complementary configuration is from 1990 documentation. The transistors must have...