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.
When you watch crime drama on TV, you don't usually see what happens after the police and ambulance leave a murder scene. One thing those people do not do is clean up the blood. That's the work of a whole different team.
If a drugstore is the equivalent of a 7-Eleven where you can pick up ready-made apple pie pockets, then a compounding pharmacy is your corner bakery where an individual tart is made just for you. But are these specialized pharmacies safe?