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    Why is the capacitance between gate and drain is almost zero after pinch off?

    Initially we have oxide capacitance between gate and body. But once we have the channel the capacitance gets distributed between source and drain. I just could get this "distribution" thing - Does that mean that there are some static negative charges in source and drain? Also after pinch off there is no capacitance between gate and drain. Why is that so?

    Thanks in advance.
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    Re: Why is the capacitance between gate and drain is almost zero after pinch off?

    Quote Originally Posted by iVenky View Post
    Initially we have oxide capacitance between gate and body. But once we have the channel the capacitance gets distributed between source and drain. I just could get this "distribution" thing - Does that mean that there are some static negative charges in source and drain? Also after pinch off there is no capacitance between gate and drain. Why is that so?

    Thanks in advance.
    Hi friend.........

    I think the current Igs is zero, so there is no capacitance between drain and gate.
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  3. #3
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    Re: Why is the capacitance between gate and drain is almost zero after pinch off?

    The channel is what connects gate plate capacitance to the drain
    (and source). When the channel goes away only the overlap &
    fringing capacitance is "hooked up", the rest is returned to body
    instead of the inversion sheet when not inverted.



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