CS amplifier problem.

Discussion in 'General Electronics Chat' started by alphacat, Nov 5, 2009.

  1. alphacat

    Thread Starter Active Member

    Jun 6, 2009
    186
    0
    Hey,

    I built up the following circuit and for some reason I received VG = 0.38V, instead of VG = VCC/2.

    I have measured the resistance of RG2 when it was connected to the circuit, and the Fluke read 3.1KΩ.

    When I picked up RG1=RG2=100Ω, then VG was indeed VCC/2.

    Could someone explain it to me please?
    Does the Gate-Source have some kind of resistance? (around 3KΩ)

    Thank you.

    [​IMG]
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,646
    2,345
    Hello,

    Did you connect it correctly?

    [​IMG]

    Greetings,
    Bertus
     
  3. The Electrician

    AAC Fanatic!

    Oct 9, 2007
    2,281
    326
    You have probably damaged your MOSFET. Try a new one in the circuit.
     
  4. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    I think electrician has nailed it. Extra care should be used when handling MOSFET devices. They are much more likely to be damaged by electro-static discharge than their BJT cousins.

    hgmjr
     
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