Found in an Electronics Now from the 90s, this circuit is used to control the supply of accessories in the car. Components are common today.
This is the traditional configuration of na Astable Multivibrator using two NPN ttransistor....
This circuit was adapted from an Italian publication that no longer exists. This is “Onda Quadra”...
This FET stage circuit was obtained from old American documentation but can be applied to any FET....