When a voltage (V DS) is applied between drain and source terminals and voltage on the gate is zero, the two PN junctions at the sides of the bar establish depletion layers. In a n-channel FET, the gate and the channel from a PN junction, the gate arrow points inwards and in p-channel FET, the gate and channel from an PN junction, the gate arrow points outward. The vertical line in the symbol can be visualized as the channel to which the source and drain are connected. The third terminal gate is connected at the center of the vertical line. The schematic symbol of a FET is shown in figure. Thus a FET has essentially three terminals viz., gate (G), source (S) and drain (D). Other terminals of FET are source and drain taken out from the bar. The two PN junctions that make up the diode are connected internally and the common terminal is called a gate. When the bar FET is of n-type, it is called n-channel FET and when the bar of FET is of p-type, it is called p-channel FET. The bar forms the conducting channel for the charge carriers. The FET has high input impedance and low noise level.Ī FET consists of a p-type and n-type silicon bar containing two PN junctions at the sides. either by holes or electrons and is controlled by the effect of electric field. It is a three terminal semiconductor device in which current conduction is by one type of charge carrier, i.e.
0 Comments
Leave a Reply.AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |