The skin is composed of two layers: the epidermis and the dermis. Underneath these layers lies the hypodermis. The epidermis is stratified squamous epithelium. The dermis is composed of a papillary layer and a reticular layer. The reticular layer of the dermis is made up of dense irregular connective tissue. The hypodermis is a layer of loose connective tissue.
The Hall effect is the production of a voltage difference (the Hall voltage) across an electrical conductor, transverse to an electric current in the conductor and a magnetic field perpendicular to the current.It was discovered by Edwin Hall in 1879.all effect in semiconductors [edit]. When a current-carrying semiconductor is kept in a magnetic field, the charge carriers of the semiconductor experience a force in a direction perpendicular to both the magnetic field and the current. At equilibrium, a voltage appears at the semiconductor edges.
Hall sensors are commonly used to time the speed of wheels and shafts, such as for internal combustion engine ignition timing, tachometers and anti-lock braking systems. They are used in brushless DC electric motors to detect the position of the permanent magnet.