Discussion in 'General Electronics Chat' started by f45hil, Feb 24, 2012.

  1. f45hil

    Thread Starter New Member

    Feb 24, 2012
    In which region MOSFET works as an amplifier and in which region MOSFET works as a switch? Does MOSFET work as a switch in the saturation region?
  2. nigelwright7557

    Senior Member

    May 10, 2008
    A MOSFET can work in the linear region for a class AB amp or in switching mode for a class D amplifier.
  3. Wendy


    Mar 24, 2008
    Generally if you need a transistor in the linear region you use a BJT, not a MOSFET. A BJT has a wider range that is truly linear, while a MOSFET is a really good switch, with a incredibly low conductance when it is on (well under 0.1Ω typically).

    If you must use a MOSFET in its linear region then be aware you are throwing away most of the advantages of a MOSFET. It will get hot, but that is true of a BJT also.

    There are logic level MOSFETs designed to work with lower voltages, but generally a conventional MOSFET requires 10V or more on the gate to turn fully on. Less than that can (not will) put it in it's linear region.