Eye Current

Field Effect Transistors

Part A
Basically there are two types of field effect transistors. One is the Junction Field Effect Transistor commonly known as a Junction FET or JFET. The other type is an Insulated Gate Field Effect Transistor (IGFET), but is referred to as a Metal-Oxide Semiconductor Field Effect Transistor (MOSFET).

Both types can be either a N-Type or P-Type material (usually made of silicon) used to make the conducting current carrying channel. Both the JFET and the MOSFET are controlled by voltage on the gate. The bipolar transistors are controlled by current on the base. The JFET uses reverse-bias gate-to-source giving this unit a very high input resistance, where as the bipolar transistors base-to-emitter is forward-biased giving the transistor a low input resistance.

In the JFET, the gate is connected to the conducting channel and in the MOSFET, the gate is insulated from the conducting channel.

Labels: Tutorial

posted by Elvin S. @ 11:27 AM