Which of the following is not true for JFET?

Detailed Explanation of the JFET Concept:

The Junction Field-Effect Transistor (JFET) is a type of field-effect transistor that is widely used in electronic circuits. It is a voltage-controlled device with three terminals: the Source, Gate, and Drain.

• Drain Current Control: The drain current (I_D) in a JFET is controlled by the voltage applied to the gate (V_GS) and the resulting channel width. When a reverse bias voltage is applied to the gate-source junction, the width of the conducting channel between the source and drain changes, thus controlling the current flow through the device.
• Gate-Source p-n Junction Biasing: - In a JFET, the gate-source p-n junction is always reverse biased during normal operation. This reverse biasing causes a depletion region to form, which modulates the conductivity of the channel. - Forward biasing the gate-source p-n junction is not a typical mode of operation for a JFET as it would lead to excessive current flow and loss of control over the drain current.
• Voltage-Controlled Device: The JFET is classified as a voltage-controlled device because the output current (drain current) is controlled by the input voltage (gate-source voltage) rather than the input current. This characteristic makes JFETs useful in applications requiring high input impedance and low noise.

Correct Option Explanation:

Option 2 states that "Gate-source p-n Junction is always forward biased," which is incorrect for a JFET. This statement contradicts the fundamental operating principle of a JFET, where the gate-source p-n junction is always reverse biased to control the drain current. Forward biasing the gate-source junction would compromise the device's ability to control current flow and is not a typical operating condition for JFETs.

Therefore, option 2 is the correct answer as it is the statement that is not true for a JFET.