MOSFET VS JFET | The Main Differences

The main differences between MOSFET and JFET are explained in this article. MOSFET stands for Metal Oxide Semiconductor Field Effect Transistor and JFET stands for Junction Field Effect Transistor. Before going to know the differences let's see some similarities. 

MOSFET and JFET both are the voltage controlled device.
Both of them are the unidirectional device that means they allow the flow of current in one direction only.
Both of them have same numbers of terminals with same name - Drain, Gate, Source

The Symbolic Difference between JFET and MOSFET

Here you can see the symbolic difference between JFET and MOSFET in the below figure.

difference between MOSFET VS JFET

Main Differences between MOSFET and JFET

1. JFET can operate only in Depletion Mode but MOSFET can operate in both Enhancement Mode and Depletion Mode. It is a very important difference between JFET and MOSFET.

2. JFET has less input impedance than MOSFET. The input impedance of a JFET is 109 Ω whereas the input impedance of a MOSFET is 1015 Ω

3. As the JFET has less input impedance so it provides a higher Gain but MOSFET has lower Gain compared to JFET.

4. The drain resistance of the JFET is higher than the MOSFET. The drain resistance of the JFET is 1 MΩ whereas the drain resistance of the MOSFET is 50KΩ. For this reason, the output characteristics curve of the JFET is flatter than the output characteristics of MOSFET.

5. The gate leakage current of a conventional JFET is approximate 10-8 A whereas the gate leakage current of a conventional MOSFET is 10-13 A. So it clear that JFET has more leakage current than MOSFET.

6. The JFET offers low switching speed and low flicker noise than MOSFET. As the MOSFET provides high switching speed, it is used for very high-speed switching applications.

Other differences are given below.


1. The fabrication process of the MOSFET is easier than the fabrication of JFET because a metal layer is used in MOSFET.

2. JFET can work only reverse input voltage, it cannot work properly if the forward input voltage is given but the MOSFET work with both, in fact, it can work with the large input voltage.

3. JFET provides very low noise than MOSFET although the MOSFET has a very high switching speed than JFET. High speed switching means high noise.

4. The JFET has less propagation delay compared to the MOSFET because there is more capacitive effect occurs in MOSFET.

5. JFET is used in small amplifiers, electronic switches, digital circuits, sensitive circuits where very low noise is mandatory but MOSFET is used in Motor speed control circuits, power amplifier circuits, inverter circuits, etc where high-speed switching is mandatory.

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MOSFET VS JFET | The Main Differences MOSFET VS JFET | The Main Differences Reviewed by Author on July 10, 2019 Rating: 5
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