This type of answering machine was common at the time this circuit was published. Using two tape recorders, it was published in the June 1986 issue of Radio Electronics magazine.
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...