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help identifying this component (capacitor)? [Solved]

Discussion in 'Datasheets, Manuals or Parts' started by Protonus, Feb 18, 2015.

  1. Protonus

    Protonus New Member

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    Hi folks. Below is the circuit board out of a NewTrent USB battery charger. I believe I had a bad MicroUSB cable that I used with it one day and it stopped working. Opened it up to find this. Obviously I've to one or more failed components there, looks like it dead shorted the full 2 amps it outputs thru it.

    I'm guessing the scorched component is a filter capacitor, but beyond that, I'm not sure. I've never ran across this particular package before. Few questions:

    1.) Is it a cap?
    2.) If it's a cap, is it electrolytic?
    3.) It says 100 10V on it. Is that 100 uf, 10 Volts? Or 100 mf, 10 Volts?
    4.) Anyone know what brand that X symbol represents?
    5.) Is the red stripe for the positive end of the cap?

    Thanks so much in advance!

    NewTrent board.jpeg
     
  2. throbscottle

    throbscottle Well-Known Member

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    It's a 100uF 10v tantalum cap. Pretty sure the stripe is +. (opposite marking scheme to aluminium electrolytics)
     
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  3. Tony Stewart

    Tony Stewart Well-Known Member Most Helpful Member

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    POssible short or excessive ripple current with an aging battery.

    Of course a loose USB contact wreaks havoc with surge currents which might cause heat in connector and capacitor.

    If the ESR of the aging battery exceeds the ESR of C16, then the Cap takes more but not all the AC ripple current with I²ESR dissipation and possibly shorted now.


    Choose a replacement with low ESR. They range from 50 mΩ to >1 Ω in this size.
     
    Last edited: Feb 18, 2015
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  4. dave

    Dave New Member

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  5. throbscottle

    throbscottle Well-Known Member

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    That's interesting. So this thing could never be run with no load then? (unlikely to happen I know, but it's interesting!)
     
  6. Tony Stewart

    Tony Stewart Well-Known Member Most Helpful Member

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    Not quite.. The battery has effectively much higher capacitance and DC current depends on state of charge.
    So there would not be any significant AC ripple with no load. But a lossy battery could have less AC ripple current than the Caps.
     
  7. Protonus

    Protonus New Member

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    Thank you so much for the help folks. Now that I know what this is (I've only ever worked with the "bead" style Tantalum's before), I measured it, it's a C - case. I looked at digikey, and sought replacements that weren't very pricey, yet had a low ESR (thanks for the tip!). I picked out this one, and ordered a few of them: http://www.digikey.com/product-detail/en/TR3C107K010C0100/718-1324-1-ND/1663046

    It had a 10% tolerance, and is 100 mOhm ESR, which I assume should be low enough, as there weren't many much lower than that. Hopefully will be replacing it soon!
     
    Last edited: Mar 30, 2015
  8. Protonus

    Protonus New Member

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    Hey folks, sorry I forgot to update this. But I soldered in the new caps I ordered above in my prior post and.... it's all fixed and working great! Thanks so much for all your help!
     
  9. Tony Stewart

    Tony Stewart Well-Known Member Most Helpful Member

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  10. throbscottle

    throbscottle Well-Known Member

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    I'd never heard of those - are all SMD electrolytic caps in the round aluminium cans of this type? I must have dozens on various scrap boards!
     

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