Types of Transistors

Types of Transistors

The letters N and P here refers to the layers of semiconductor material used to make the transistor.
The transistor are of two types:

1. NPN: when a p-type is sandwiched between two n-type, the resulting transistor is a n-p-n transistor. Here N denotes N-doped semiconductor.
2. PNP : A p-n-p transistor is obtained by sandwiching a n-type semiconductor between two p-type semiconductors. Here P denotes P-doped semiconductor.

   
   

Graphene Transistors

The modern transistors are based on semiconductor technology. The numbers of transistors on the single chip are quickly reaching its physical limits. The scientists all over world are working on alternative of semiconductor.
In 2006, Walter de Heer and his team had successfully built an all-graphene transistors. The graphene is one atom thick pure carbon layer.
The advantage of using graphene as a substitute is that it offer very little resistance to the flow of electrons so it can perform large number of operations without heating much and moreover it is good thermal conductor so the heat can be dissipated from it very quickly.