FET Miller Sweep - Transient Response

Discussion in 'Homework Help' started by chrispo86, Jan 30, 2009.

  1. chrispo86

    Thread Starter New Member

    Jan 28, 2009
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    I've been given the attached circuit and been told to sketch the output from 0+ <= t <= ∞. I believe I'm correct in stating that the voltage across the cap at time 0+ is ecap = 9V, and the voltage at the output is eo(0+) = Vgs + 9V, and Vgs would be 0.7V so it would be 9.7V. At least, this is what it was in a similar problem which we did in class, so correct me if I'm wrong.

    This is where I get lost. I know the next step would be to find eo(∞). The capacitor would be replaced by an open once it reaches steady-state, so it can be taken out of the circuit, leaving the circuit in the second figure. What's confusing me is what do I do with the (gm Vgs)? Maybe it's just that I can't remember my classes where we covered transistors. It's been a couple years now.

    Thanks in advance for the help.
     
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