Earphones

Almost everyone uses earphones. It is simply a wire with earpieces and a mini plug. They can come in many different colors. Earphones can be used for many different things. They can be used for entertainment purposes, like your i-pod, DVD player, or computer. They are also used in the profesional enviroment. They are used a lot in radio and TV. Singers use them in the studio and air traffic controllers use them to communicate with pilots.
The earphone came about at the turn of the 20th century. They were commonly used for radio work in 1919 and they had poor qulity early on. They enabled you to listen to things on your own. The headphone has eveolved since then into tiny earpieces. It can hurt your hearing if you blare them too loud. Earphones act as a sound reproducer and it can do this in several ways. A moving coil is wrapped around a stationary magnetic element that is attached to the frame of the headphone, which sets up a static magnetic field. The diaphragm is attached to a coil of wire which is immersed in the static magnetic field of the stationary magnet. The diaphragm is activated by the attached voice coil, when an audio current is passed through the coil. The alternating magnetic field produced by the current through the coil reacts against the static magnetic field in turn, causing the coil and attached diaphragm to move the air, thus producing sound. There are other kinds that work in a similar way.
I use my earphones mostly when I am working out with my i-pod. They make working out so much better. I also find them useful in cars or planes when traveling. The only problem is that my ears are really tiny, so somethimes they really hurt my ears.