Inconsistent symbol

Discussion in 'Feedback and Suggestions' started by Unregistered, Nov 10, 2009.

  1. Unregistered

    Thread Starter Guest

    http://www.allaboutcircuits.com/vol_3/chpt_3/8.html

    In the Cockroft-Walton schematic at the end of the page, inconsistent symbols are used for the capacitors, implying (to me) that one is polarized and the others unpolarized.

    I have no idea what would be correct.
     
  2. Wendy

    Moderator

    Mar 24, 2008
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    Polarized capacitors are used with DC, because you can get much smaller sizes that way. There isn't any difference between them other than polarization. A 10µF polarized is the same as a non-polarized 10µF cap as long as it isn't being used for AC. The conventions as used are valid.

    Oddly enough, if you put two polarized caps of the same value back to back they are equivalent to an unpolarized cap that is half the value.

    A lot of what might be confusing is the plus and minus symbols, used to illustrate the voltages and polarities as distributed through the circuit.

    I assume this is the illustration that is bothering you...

    [​IMG]

    If you want to discuss theory please register. If you still think the AAC book has an issue this is the place to discuss it.
     
  3. Unregistered

    Thread Starter Guest

    "The conventions as used are valid."

    I don't disagree.

    "If you still think the AAC book has an issue this is the place to discuss it. "

    The schematic I'm referring to has one cap indicated as polarized, and all the others in that "chain" are shown as unpolarized. With my bit-pusher's view, I'd see no reason why that particular one would be polarized and none of the others. thus, I think it is probably an error in that schematic.
     
  4. Wendy

    Moderator

    Mar 24, 2008
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    You're talking as if it is a different part, it isn't, both are capacitors. In the schematic it is shown it is part of a DC circuit. Either work identically in that context.

    The editor of the book (which I am not) will be here eventually and make the call.
     
  5. AlexR

    Well-Known Member

    Jan 16, 2008
    735
    54
    Bill;
    I imagine that op is referring to the diagram below and the capacitor that is connected to earth.
    For some unknown reason it is drawn using a polarised capacitor symbol while all the other capacitors of the same value are shown as unpolarised.

    But the example you refered to is also wrong since I very much doubt that you would be able to find a 1000 picofarad electrolytic capacitor. Either the symbol is wrong or more likely the value should be uF rather than pF.

    [​IMG]
     
  6. Wendy

    Moderator

    Mar 24, 2008
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    Hmmm, I'd missed that picture. It'll be easy enough to fix though.
     
  7. Dcrunkilton

    E-book Co-ordinator

    Jul 31, 2004
    416
    11
    I have updaed image 03288.eps, 03288.png to show unpolarized capacitors only. thanks for pointing out this inconsistency. I will post back here when I upload to ibiblio.
     
  8. Dcrunkilton

    E-book Co-ordinator

    Jul 31, 2004
    416
    11
    I have updated the ibiblio copy for numerous corrections (not just for this thread) over the last few days. The list of affected files and images follows:
    DC V1:dcmeter.sml contrib.sml 00502.png
    AC V2:basicac.sml contrib.sml
    Semi V3: bjt.sml diode.sml contrib.sml theory.sml 03288.png 03304.png 03392.png
    Digital V4: boolean.sml contrib.sml
     
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