Shingles is the reactivation of a viral infection in the nerves to the skin that causes pain, burning, or a tingling sensation, along with an itch and blisters in the skin supplied by the affected nerve. It is caused by the varicella zoster virus[1] , or VZVâthe same virus that causes chickenpox.
Types of electrical circuits. There are three main types of circuits encountered in a domestic situation. They are ring circuits, radial circuits and lighting circuits.
Types of transistor. There are two types of standard (bipolar junction) transistors, NPN and PNP, with different circuit symbols. The letters refer to the layers of semiconductor material used to make the transistor. Most transistors used today are NPN because this is the easiest type to make from silicon.here are two types of standard (bipolar junction) transistors, NPN and PNP, with different circuit symbols. The letters refer to the layers of semiconductor material used to make the transistor. Most transistors used today are NPN because this is the easiest type to make from silicon.