The main difference this time is that MOSFETs are available in two basic forms:ġ.

Like the previous JFET tutorial, MOSFETs are three terminal devices with a Gate, Drain and Source and both P-channel (PMOS) and N-channel (NMOS) MOSFETs are available. Also like the JFET, this very high input resistance can easily accumulate large amounts of static charge resulting in the MOSFETbecoming easily damaged unless carefully handled or protected. The isolation of the controlling Gate makes the input resistance of the MOSFET extremely high in the Mega-ohms ( MΩ ) region thereby making it almost infinite.Īs the Gate terminal is isolated from the main current carrying channel 'NO current flows into the gate' and just like the JFET, the MOSFET also acts like a voltage controlled resistor were the current flowing through the main channel between the Drain and Source is proportional to the input voltage. This insulated metal gate electrode can be thought of as one plate of a capacitor. The IGFET or MOSFETis a voltage controlled field effect transistor that differs from a JFET in that it has a 'Metal Oxide' Gate electrode which is electrically insulated from the main semiconductor N-channel or P-channel by a thin layer of insulating material usually silicon dioxide (commonly known as glass). The most common type of insulated gate FET which is used in many different types of electronic circuits is called the Metal Oxide Semiconductor Field Effect Transistoror MOSFET for short. Round Shell Connector/Aviation ConnectorĪs well as the Junction Field Effect Transistor (JFET), there is another type of Field Effect Transistor available whose Gate input is electrically insulated from the main current carrying channel and is therefore called an Insulated Gate Field Effect Transistor or IGFET.

Fet transistor tutorial