2/26/2024 0 Comments Fet transistor lecture in hindiThe flow of electrons from source to drain is now restricted to the narrow channel between the no conducting depletion regions. Therefore the depletion region width increases as we move towards drain. ![]() Both depletion regions are therefore subject to greater reverse voltage near the drain. The potential at any point along the channel depends on the distance of that point from the drain, points close to the drain are at a higher positive potential, relative to ground, then points close to the source. The conductivity of this channel is normally zero because of the unavailability of current carriers. The depletion region width increases with the magnitude of reverse bias. The current carriers have diffused across the junction, leaving only uncovered positive ions on the n side and negative ions on the p side. The word gate is used because the potential applied between gate and source controls the channel width and hence the current.Īs with all PN junctions, a depletion region is formed on the two sides of the reverse biased PN junction. 2.īoth the gates are internally connected and they are grounded yielding zero gate source voltage (V GS =0). These impurity regions are called gates (gate1 and gate2) as shown in fig. Now on both sides of the n-type bar heavily doped regions of p-type impurity have been formed by any method for creating pn junction. If V DS increases, I D increases proportionally. The resulting current is the drain current I D. Hence the circuit behaves like a dc voltage V DS applied across a resistance R DS. For an N-channel device, electrons are the majority carriers. The terminal through which majority carriers leaves the channel is called drain and designated by D. The terminal from where the majority carriers (electrons) enter the channel is called source designated by S. Thus if a voltage is applied across the bar, the current flows through the channel. Ohmic contacts are then added on each side of the channel to bring the external connection. This is called N-channel and it is electrically equivalent to a resistance as shown in fig. The main disadvantage is its relatively small gain bandwidth product in comparison with conventional transistor.Ĭonsider a sample bar of N-type semiconductor. It exhibits no offset voltage at zero drain current. It is less noisy than a bipolar transistor. The input to FET involves a reverse biased PN junction hence the high input impedance of the order of M-ohm. The input to conventional transistor amplifier involves a forward biased PN junction with its inherently low dynamic impedance. In FET the operation depends upon the flow of majority carriers only. That is why it is called bipolar transistor. In a conventional transistor, the operation depends upon the flow of majority and minority carriers. Measurements with the cathode ray oscilloscope.Principle and types digital instruments.Introduction of minimization using K-map.Nonassociativity of NAND and NOR Gates: universal gates.Basic Theorems & Properties of Boolean algebra.Sign-and-magnitude method:2s complement Representation.Rules of Binary Addition and Subtraction.Conversion of decimal to binary ( base 10 to base 2).Switching Theory and Logic Design (STLD). ![]() Power Calculations for Class B Push-Pull Amplifier.Power Amplifiers: Biasing a class B amplifier.Power Amplifiers:Cross over distortion(Class B amplifier).Analysis of a transistor amplifier using h-parameters.Biasing Techniques:Voltage Divider Bias.Biasing Techniques:Collector Feedback Bias.Relation between different currents in a transistor.Steady- State Analysis of Single Phase AC Circuits and AC Fundamentals.Biasing Techniques:Emitter Feedback Bias. ![]()
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