Transducer, in electronics, a device that converts electric energy into some other form of energy, or vice versa. Transducers are used in sound systems, in video equipment and in many measuring devices. A transducer used in a measuring device produces an electric current proportional to the strength or intensity of the physical quantity—such as heat, light, or mechanical stress—to which the transducer is subjected. Piezoelectric crystals (crystals that produce an electric current when deformed) and photoelectric cells are transducers; so are loudspeakers, which produce sound from electric energy.
We first reported on the possibility of an invisibility cloak last year. Now a different invisibility cloak is making the news -- one that uses metamaterials to redirect light away from the wearer.
Whether they're sorting out scrap metal or helping us unlock the secrets of the universe, electromagnets are pretty nifty devices. What's so great about magnetism on demand? We'll electrify you with the details in these videos.