The gate current in an ideal FET is
zero
The correct answer is zero.
In an ideal Field Effect Transistor (FET), the gate current (IG) is considered to be zero. This is because the gate is insulated from the channel by a layer of dielectric material (e.g., silicon dioxide). This insulation prevents the flow of current between the gate and the rest of the transistor. In reality, there is a very small leakage current, but this is usually negligible compared to other currents in the circuit and is treated as zero in ideal analysis.
Let's examine why the other options are incorrect:
- Equal to the drain current: This is incorrect. The drain current (ID) is controlled by the gate-source voltage (VGS), not directly related to the gate current.
- Very high: This is incorrect. A high gate current would indicate a significant short circuit, which is not characteristic of a correctly functioning FET.
- Proportional to the source current: This is incorrect. The source current (IS) is related to the drain current, but neither is directly influenced by the gate current in an ideal FET.
The near-zero gate current characteristic is a key advantage of FETs, leading to high input impedance and low power consumption, making them suitable for various applications.
Similar Questions
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Important Questions from Field Effect Transistors
Which of the following is the characteristic of Field-effect transistor?
- In junction field effect transistor, the drain current can be approximated as:
The expression for the transconductance (g m) of a JFET is:
Field Effect transistor is:
A FET has
