Current and voltage specfics for a PNP transistor or mosfet

Discussion in 'General Electronics Chat' started by Drmario5237, Apr 24, 2019.

  1. Drmario5237

    Thread Starter Member

    Oct 14, 2018
    53
    0
    Since a PNP transistor or mosfet switches off when certain amount of current or voltage is applied to it or shuts off when any current or voltage is applied to it's base can you over heat or blow up a PNP transistor or mosfet by applying to much current/voltage to it's base or will it just shut the transistor or mosfet off. Thanks.
     
  2. danadak

    Distinguished Member

    Mar 10, 2018
    3,068
    685
    In case of MOSFET if Vgs gets too high the gate oxide will rupture internally
    causing (typically) a short and is destructive.

    In case of Bipolar too much base current can create extreme junction heating,
    can melt internal silicon, can destroy gain of transistor, can simply wind up
    shorting one or more junctions.

    Regards, Dana.
     
  3. BobTPH

    Senior Member

    Jun 5, 2013
    1,740
    446
    Where did you get that idea?

    Current in the base emitter junction turns a PNP or NPN transistor on, not off.

    Bob
     
    Last edited: Apr 25, 2019
  4. Wolframore

    Active Member

    Jan 21, 2019
    743
    202
    In fact this is why the mosfets are sensitive to electrostatic discharge. High voltage from ESD can permanently damage mosfets and should handled with care before they are placed in circuitry. This includes ICs.
     
  5. crutschow

    Expert

    Mar 14, 2008
    22,231
    6,483
    The data sheet for a specific device will tell you the maximum voltages and currents it can tolerate.
     
  6. wayneh

    Expert

    Sep 9, 2010
    16,099
    6,212
    It will be destroyed. Unlike some ICs, a discrete transistor has no overload protection. If you exceed the specifications, you risk immediate failure. And since transistors can fail to a short, they can bring down other components as well. Many devices will have a fuse on board to prevent a transistor failure (or other problem) from causing a fire.
     
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