JFET and MOSFET comparison

jojo September 8, 2009 17 Comments



JFETs and MOSFETs are quite similar in their operating principles and in their electrical characteristics. However, they differ in some aspects, as detailed below :



  1. JFETs can only be operated in the depletion mode whereas MOSFETs can be operated in either depletion or in enhancement mode. In a JFET, if the gate is forward biased, excess- carrier injunction occurs and the gate current is substantial. Thus channel conductance is enhanced to some degree due to excess carriers but the device is never operated with gate forward biased because gate current is undesirable.
  2. MOSFETs have input impedance much higher than that of JFETs. This is due to negligibly small leakage current.
  3. JFETs have characteristic curves more flat than those of MOSFETs indicating a higher drain resistance.
  4. When JFET is operated with a reverse bias on the junction, the gate current IG is larger than it would be in a comparable MOSFET. The current caused by minority carrier extraction across a reverse-biased junction is greater, per unit area, than the leakage current that is supported by the oxide layer in a MOSFET. Thus MOSFET devices are more useful in electrometer applications than are the JFETs.

For the above reasons, and also because MOSFETs are somewhat easier to manufacture, they are more widely used than are the JFETs.

  • jayanarayan sahoo
    January 23, 2015

    thanks for clear my doubt..plz send me the details about MOSFET and difference between the DMOSFET and EMOSFET

  • Asish GB
    November 20, 2011

    Very useful description. Nice website. Thanks..

  • shijin
    July 26, 2011

    pls send me some difference betweens of jfet and mosfet

  • sisir maity
    May 31, 2011

    thanks for making such a useful wabeside

  • Sreedilal
    July 30, 2010

    Plz send some details about PCB Designing…..Free Software Or Related sites…..

  • June 17, 2010

    All the Description about JFET, & MOSFET is perfect specially performing my Electronic Circuits Experiments.
    I am thoroughly studying .

    Engineer Rashid

    February 20, 2010

    plz send me about these verifications

  • vrijeshpandey
    January 24, 2010

    your descriptions are very logical.

  • vrijeshpandey
    January 24, 2010

    your discriptions are very logical.

  • vikas
    January 14, 2010


  • suresh
    September 16, 2009

    this website is amazing

    September 10, 2009

    thanks for sending e-mail.i am really very happy with your services.that is very useful for me because it is totally related to my study.ones again thanks.

Leave a Reply