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Transistor equivalent resistance

  1. Dec 1, 2008 #1
    Hi all:

    I am trying to design an LNA using an Hewlett Packard BJT, model AT-31011. The equivalent resistance at the frequency of interest is given as RN = 0.18; this is very strange to me because I am used to getting RN values closer to 20. I tried to use this RN value to plot a constant noise figure circle on a Smith Chart, but since the RN was so small, the circle was almost the same size as the entire Smith Chart! Can someone please clarify the issue here :D Maybe I need to use a different set of formulas to get the constant noise figure circle? Any help is appreciated!
  2. jcsd
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