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What does this circuit diagram mean?

  1. Sep 13, 2009 #1
    The attached picture shows four diagrams that I do not understand. To me electrical diagrams have to be circular and closed in nature, thats why these confuse me.

    Once that question is answered I need to understand why II and III act as a high pass filter.


    Attached Files:

  2. jcsd
  3. Sep 13, 2009 #2


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    The attached picture does not seem to be working. Could you try attaching it again?

    Edit.........The diagram has to be renamed as a PNG file. Now it works.

    These drawings are just part of a circuit and assume you have something like a signal generator on the left and an oscilloscope on the right.

    To work out what would happen in each case you regard the two devices as a voltage divider and work out what would happen to the reactance of the capacitor and inductor as you change frequency.

    For example, the formula for reactance of an inductor is
    XL = 2 * Pi * F * L where F is frequency and L is the inductance in Henries.
    Can you see that if the inductance stayed the same, the reactance would go up as frequency goes up?
    So, what would happen if the inductor was in a voltage divider? Depends if it was at the top or the bottom, doesn't it?

    Then do the same for the capacitor
    XC = reciprocal of ( 2 * Pi * F * C)

    Note that the actual voltage you would get is not exactly like you would get with resistors in series. In diagram 1, the inductor has a higher reactance as the frequency increases so the output decreases.
    Look up LCR networks somewhere and get more detail if you like.

    Attached Files:

    Last edited: Sep 13, 2009
  4. Sep 13, 2009 #3
    sorry for the image... and thanks to vk6kro for fixing my mistake.

    I don't understand how the circuit gets completed... does it look something like the image i have attached now (second image.jpg)[this one works, check on my windows box]

    I understand the inductance I just don't understand how to interpret the diagram.

    thanks Dominik

    Attached Files:

  5. Sep 13, 2009 #4


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    Yes, that is all.

    It is just a part of a circuit shown like this to show the principle.
  6. Sep 13, 2009 #5
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