Advantages of FET | disadvantages of FET

This page covers advantages and disadvantages of FET. It mentions FET advantages or benefits and FET disadvantages or drawbacks.

What is FET?

Introduction:
FET is the short form of Field Effect Transistor. It is called unipolar transistor as current flow is carried out by majority charge carriers only. FET transistor is controlled by voltage rather than current unlike BJT.

Refer FET versus BJT >>. Following are the advantages of FET over BJT.

Based on the principle of operation and construction, FETs are classified as follows.
• JFET-Junction Field Effect Transistor
• MESFET-Metal Semiconductor Field Effect Transistor
• HEMT-High Electron Mobility Transistor
• MOSFET-Metal Oxide Semiconductor Field Effect Transistor

Benefits or advantages of FET

Following are the benefits or advantages of FET:
➨High input resistance
➨Low noise figure
➨High efficiency as compare to BJT
➨Operating frequency range is higher compare to conventional BJT transistor.

Drawbacks or disadvantages of FET

Following are the disadvantages of FET:
➨It has relatively lower gain-bandwidth product compare to BJT.
➨Transconductance is low and hence voltage gain is low.
➨FET has slower switching times compare to BJT. The internal junction capacitance of FET is responsible for high delay times.
➨FET performance degrades as frequency increases. This is due to the feedback by internal capacitance.
➨They are more costly compare to junction transistors.
➨FET of MOSFET type is very susceptible to overload voltages, hence special handling is required during installation.
➨In MOSFET, the layer between Gate and Channel is very fragile which is vulnerable to electro-static damage during installation. Once it is installed in a well designed circuit, there is no issue found.