From a construction point of view, these are N or P channels, as is evident from symbols. In figure 5.1, the construction of FET(Field Effect Transistor) and its symbols have been portrayed. It is a vacant space between two gates through which the majority of carriers pass from source to drain (supplying V DS voltages from drain to source) or the conductive path of a semiconductor found between source and a drain, which is called a channel. This terminal junction resembles a junction transistor’s base. Input signal voltage is supplied on the gate. Gate source voltage (V GS) reverses the bias of a gate. Gate are two mutually interconnected heavy doped regions, which form two P-N junctions. In other words, it is an electrode, which controls channel conductance found between a source and drain. Through variations in it, the conductivity of a channel can be modulated. It is a control terminal of a FET(Field Effect Transistor) which generates an electric field. This FET terminal resembles a BJT collector. In other words, it is such a terminal by means of which current passes out from the channel. Drain to source voltage (V DS) operates drain current (I D). It is a terminal through which the majority of carriers emit. In other words, it is a terminal, through which charge carriers penetrate into the channel bar.

It is a terminal, through which the majority of carriers pass. holes and electrons).įollowing terms regarding a “FET(Field Effect Transistor)” should be indoctrinated in mind. Whereas operation of bipolar junction transistors (BJTs) depends on the movement of both charge carriers (i.e. Remember, the operation of a FET(Field Effect Transistor) depends on the movement of only one charge carrier (holes or electrons), due to which are called unipolar junction transistors (UJTs). Gate input resistance of FET(Field Effect Transistor) is very high, therefore, a very low current passes through its gate. Through changing gate voltages, the charge is provided via changing resistance found between source and drain. Voltages are supplied on the gate of the field-effect transistor. Terminals of an ordinary transistor are known as emitter, base, and collector while three terminals of a field-effect transistor are known as source, gate, and drain respectively. This particular component is a voltage control amplifier. Apart from the field-effect transistors, the rest of the transistors are current amplifiers. The basic difference between a transistor and a vacuum tube is that a transistor is controlled via current, whereas a vacuum tube is controlled through voltage. In other words, the main current (between source and drain) of the FET(Field Effect Transistor) is controlled through the electric field effect caused as a result of voltages supplied between source and gate.

Introduction of Field-Effect TransistorsĪ field-effect transistor (briefly called FET) is a unipolar semiconductor device that like a bipolar junction transistor, consists of three terminals (like vacuum tubes), in which current is controlled through an electric field.

Field effect transistor