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When the Large negative bias is applied: When the large negative gate to source voltage is applied, then this large negative electric field will contribute to increment of the width of the depletion region.Besides, the current flowing from drain to source flows from the region of high resistance to low resistance, thus the voltage drop will be created.

This is because the gate is more negative at the points which are nearer to drain than to source. The width of the depletion region is more near the drain terminal and less near the source terminal.

This is because as the width of the depletion layer increases the space provided for electrons to flow from source to drain will decrease and eventually the drain current decreases. The wedge shape depletion layer so formed will reduce the magnitude of the current through the N-channel. Due to this the width of the depletion region is more in N-Channel than in P-channel. The N-channel is moderately doped while P-channel is highly doped.

Simultaneously, the positive voltage is applied to the drain to the source terminal. when the gate to source voltage is negative, then the width of depletion region starts increasing.

When small negative bias is applied: When a small negative voltage is applied to the gate terminal i.e.

The ohmic contacts are made at drain, gate and source to provide the connection. Thus, current will flow from drain to source terminal. The direction of flow of current is opposite to the direction of flow of electron. The electrons will flow from source terminal to gate terminal. In this case, the width of depletion region will remain constant. Besides, the voltage at drain terminal is also 0. It means the gate to source voltage (Vgs) in this case is 0.

When NO bias is applied: In this case, no bias is applied to the gate terminal.

Its working can be easily understood with the help of three cases. The N-channel involves the conduction due to the flow of electrons while the P-channel JFET involves conduction due to holes. The difference between these two JFETs is the current carriers involved in the conduction mechanism. To understand the working characteristics of JFET we need to consider one type of JFET either N-channel JFET or P-channel JFET. Therefore, the output current is termed as the drain current. The Drain (D) is a terminal through which electrons enter the semiconductor bar and from through which the electrons leave the semiconductor is source (S) terminal.The output current flows from the drain terminal towards the source terminal. The electrical connection which is also known as ohmic contact are made to both ends of the P type semiconductor and are taken out in the form of two terminals called drain (D) and source (S). A single wire is taken in the form of the terminal when both the N type regions are connected internally known as the gate (G).

The two PN junctions are form by the N region and the space between that is P region is called a channel. The JFET in which the current conduction takes place only due to holes as majority charge carriers is known as P channel JFET. Its construction is similar to the N channel JFET excepts that it consist of a P type silicon bar with two N type heavily doped regions diffused on opposites sides of its middle part. The construction diagram of P channel junction field effect transistor (JFET) is shown in above figure.