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Why the output is zero??

Discussion in 'Homework Help' started by kostfere, May 26, 2012.

  1. kostfere

    kostfere New Member

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    View attachment 64554 View attachment 64555

    Hello everybody, I made in Spice the circuit that you see in the photos.
    The picture with the blue font shows the circuit, and is correct as it is from our professor.
    The other circuit was created by me in Spice and as far as I see they are the same.
    My problem is that when i run simulation is Spice the voltage output (the yellow marker) is zero when it should not be!!
    If you could help me you would also save me!!!
    Thnx a lot in advance!!
     
  2. kostfere

    kostfere New Member

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    also if someone wants to ask something more about the circuit or has an answer and i am not online feel free to contact me on Skype!!
     
  3. cowboybob

    cowboybob Well-Known Member Most Helpful Member

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    Have you considered the effect of your grounding schemes?
     
    Last edited: May 26, 2012
  4. dave

    Dave New Member

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  5. crutschow

    crutschow Well-Known Member Most Helpful Member

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    I believe you have the N-channel and P-channel MOSFETS interchanged (look at the N and P designations). The symbol your professor used for MOSFETs is not common and is drawn with the arrow in the source lead (similar to a BJT symbol having the arrow in the emitter lead) instead of in the substrate lead as your symbols do. When you do that, the arrow directions are reversed.
     
  6. panic mode

    panic mode Well-Known Member

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    in addition to previous comments, you may want to check to circuit, and in particular voltages.
    second image shows four of them (Vdd, Vss, Vin, Vbias) while your schematic only has three.
     
  7. WTP Pepper

    WTP Pepper Active Member

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    If you could draw the circuit in a more conventional standard may help yourself to understand.
     

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