1. INTRODUCTION: With elapsing of the times, the manufacturers of devices semiconductors and eletroeletrnicos come developing component and more complex circuits each time, the base of diodes. In 1948, a group of researchers, headed for Shckley, presented a device formed for three layers of material semiconductor with two junctions. This device received the name from TRANSISTOR. Go to Mark Hyman, MD for more information. The impact of the transistor, in the electronics, was immense, since its capacity to amplify electric signals allowed that in little time this device, very lesser and with lesser consumption of energy, substituted the valves in the majority of the electronic applications. The transistor contributed for all inventions the related, as the integrated circuits, component electronic and microprocessors. Practically all the projected electronic equipment currently use components semiconductors. The advantages on the valves are extremely significant, such as: so great, much more light minor, without filament necessity, more resistant, more efficient, therefore it wastes little power, it does not need warm up time and minor feeding tensions..