FET Basics

At this post I'll share some basics about FET (Field Effect Transistor).

• FET is a Voltage controlled device (Were BJT is a Current controlled device.)
• FET also have 3 terminals like BJT.

    The three terminals of a field effect transistor are named gate, drain and source, which are the valve, output and input in the above analogy. The mechanism behind the operation of a FET is the exploitation of a doped semiconductor. Depending upon how the semiconductor was doped, a certain type of field needs to exist for electrons to be able to pass from source to drain. Control of this field is through the gate terminal.

Construction:
    FETs are traditionally made from silicon, although other semiconductors are used as well. The main body of the FET is doped based upon if the FET is N-type and P-type, while the source and drain are doped in an opposite way. Between them, an insulating oxide is present to which the gate is connected. Applying a voltage to the gate will permit or prohibit electrons from flowing between source and drain.

The most common FET, used in every digital device, is the metal oxide semiconductor field effect transistor, or MOSFET. The MOSFET typically employs a silicon dioxide layer between the gate and body of the FET.
Other types of FETs include the

• JFET
• MESFET
• MODFET
• FREDFET and quite a number more.

Ok, Thats fine about FET, After this i'll post biasing and connections for FET as soon as possible

reference: http://www.ehow.com/about_5181217_fet-basics.html