This old automotive circuit was found in an August 1971 Radio Electronics magazine article. The transistor is a Darlington transistor rated for the wattage of the bulb.
This circuit activates a water pump when the sensors detect lack of humidity in a vessel, for...
This circuit was obtained from an Electronics World of 1969. General-purpose transistors can be...
This circuit was found in many record players with crystal phono pickups. The output power is 800...