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Capture CIS PSpice

  1. Oct 12, 2006 #1
    Hi...I'm trying to learn how to use these programs. I have the demo versions of OrCad 10...The whole suite. I've been trying to lay out a basic 1-channel audio amplification schematic. I've attached what I have so far. Can someone explain to me how to add a power source, and how to simulate this?

    Attached Files:

    Last edited: Oct 12, 2006
  2. jcsd
  3. Oct 12, 2006 #2


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    I don't see an attachment :confused:
  4. Oct 13, 2006 #3


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    Staff: Mentor

    For adding a power source, do you just mean Place Power.... ? Or do you mean something else as in the sense of an AC source to use in an AC simulation?

    Also, there is an error in the potentiometer portion of your schematic. (Beyond the strange choice of value 500k.) Hint -- why is zero wiper current a bad idea with a potentiometer?
  5. Oct 14, 2006 #4
    Yes, how do I add an AC source? Also, can you maybe fix what is wrong with it and send it back to me? Thanks a lot.
  6. Oct 14, 2006 #5
    Are you using PSPICE or the orcad lite suite?

    In PSPICE you can add the part:

    And example setting would be:

    This gives you a 2Vpp sinusoid at 1kHZ.

    The orcad version is much more involved (from my limited use of it), and it would probably be more beneficial to pick up a tutorial/guide book.

    EDIT: I just looked at your file, and I see that you are using the orcad suite. I have a different parts library (it came with the tutorial). I believe we used VAC as the part. It might be best to just disregard what I said above, and wait for someone who is more knowledgable to help you.

    I hope I didn't add any confusion.
    Last edited: Oct 14, 2006
  7. Oct 16, 2006 #6


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    Staff: Mentor

    It's not hard to fix. Just make sure that you run some current through the wiper of any potentiometer. The pot datasheet may list a number, or you can just use a few percent of whatever the main pot current is. The issuse is that if there is zero or almost-zero wiper current, the contact can become noisy over time. An opamp input current is generally too low to qualify, so you need to configure your pot circuit to have some wiper current included.
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