====== Transistor ======

{{ :neonking:transistor.jpg?direct&300 |}}

===== Introduction =====

A Transistor is a device composed of semiconductor material that **amplifies a signal or opens or closes a circuit**, like a switch. 

It can cause changes in a large electrical output signal by small changes in a small input signal. That is, a weak input signal can be amplified (made stronger) by a transistor. For example, very weak radio signals in the air can be picked up by a wire antenna and processed by transistor amplifiers until they are strong enough to be heard by the human ear. 

A transistor consists of three layers of silicon or germanium semiconductor material. Impurities are added to each layer to create a specific electrical positive or negative charged behavior. "P" is for a positive charged layer and "N" is for a negative charged layer. 

Transistors are either **NPN** or **PNP** in the configuration of the layers. 

<wrap info>**BC547 / BC557 / BC337** are useful costless references to test with</wrap>

=====Transistor Specifications=====
  * Polarity: NPN, PNP 
  * Vce
  * Wattage Dissipation