transistor manufactured using semiconductors.For a long time they did not recognize, using a variety of devices to create only conductors and insulators.Such devices have many disadvantages: low efficiency, high power consumption and short life.The study of the properties of semiconductors became a turning point in the history of electronics.

electronic conductivity of various substances

All substances in their ability to conduct electrical current are divided into three groups: metals, dielectrics and semiconductors.Dielectrics are so named because they are not able to practically carry current.Metals have superior conductivity due to the presence in them of free electrons, which move chaotically among the atoms.When an external
electric field, the electrons begin to move toward the positive potential.At current metal held.

Semiconductors able to conduct current metal worse, but better insulators.Such substances are the main (electrons) and non-core (holes) electric charge carriers.What hole?This lack of a single electron in the outer atomic orbital.The hole is able to move through the material.With special impurities donor or acceptor, can significantly increase the number of electrons and holes in the starting material.N-semiconductor can be obtained by creating an excess of electrons and the p-conductor - with an excess of holes.

diodes and transistors

diode - a device obtained by connecting n- and p-semiconductors.He played a huge role in the development of radar in the 40's of last century.Studying its options active in the American team of employees of Bell headed by UBShokkli.These people invented the transistor in 1948, adding to the crystal germanium two contacts.At the ends of the crystal are tiny copper tip.Features of this device made a revolution in electronics.It was found that the current through the second contact can be controlled (amplify or attenuate it) with an input current of the first contact.This is possible provided that the germanium crystal is much thinner than the copper point.

first transistors were imperfect design and rather weak specifications.Despite this, they were much better than vacuum tubes.For this invention Shokkli and his team were awarded the Nobel Prize.Already in 1955 there were diffusion transistors that outperforms germanium several times.