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.
The figure shows how to obtain clocks in phase opposition using the 4013 IC. The circuit is from a...
The assembly of this circuit with 3 transistors was described in an article in Radio Electronics magazine...
This small amplifier uses a loudspeaker as a microphone and can be used in a simple intercom. The...