Mechanical Devices are physical devices which have at least one part that moves with respect to another one of its parts. Thus a spoon is not a mechanical device, but a pair of scissors is, as are more complex devices such as vacuum cleaners and the Challenger Space Shuttle.
Electrical Devices are powered devices that require an input of electrical current (as its energy source) in order to perform its intended function(s). Electrical devices include both complex devices (for example, stereo systems or computers) and simpler ones (for example, electrical components). Some non-examples are wagon, door knocker, ball, rowboat, and bicycle.