Help Identify This Yellow Critter

Discussion in 'General Electronics Chat' started by Seeking, Mar 8, 2013.

  1. Seeking

    Thread Starter New Member

    Mar 8, 2013
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    This looks like a capacitor to me, but how would I find a replacement. I can barely read resistors (with a chart). I would be forever in your debt if I could find a place to order a couple of these.
     
  2. GopherT

    AAC Fanatic!

    Nov 23, 2012
    6,045
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    It is a 3.3 microFarad capacitor. The u is shorthand for micro in the 3u3.
     
  3. Seeking

    Thread Starter New Member

    Mar 8, 2013
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    Thank you for the quick ID. How would I go about determining what voltage I should order?
     
  4. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    6,357
    718
    What voltage does the circuit run at?

    Supply voltage? Types of components next to it, etc?

    Looks like a MLCC Ceramic Chip cap, available from 6.3V (very tiny) to 250V (large 1206 SMD). Middle range 50V are the easily used 0805 size.

    Could also be a tantalum, but I doubt it for that small of capacitance. The stripe on one side does make me wonder, though.
     
  5. Seeking

    Thread Starter New Member

    Mar 8, 2013
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    The board runs at 24v ac. These appear to connect to a pair of L2722 Op Amps for dc motor control.
     
  6. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    Across the power supply pins at the op amp IC itself, or as part of a filter?

    Are there polarity markings on the board, such as a bold edge, an edge with + on it, shaped edges, etc? Since you state AC, that puts tantalum out as a choice.

    I guess the question is, does the circuit work, or are you trying to reverse engineer the values and types from a board? Tantalum are polarized, ceramic/MLCC aren't. If the capacitor is in a location where polarity never changes, it could be either. If it is in a place where polarity does change, it would pretty much need to be ceramic.

    Both types of caps are tan/yellow, and available in that value range and voltage range.

    For 24Vac input, the 100V cap would be what I'd suggest (due to peak-peak voltages of AC). What are the dimensions of the one in the photo?
     
    Seeking likes this.
  7. MrChips

    Moderator

    Oct 2, 2009
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    Show a photo of the whole board if it is not too large and tell us where the board is from.
    Why do you want a replacement?
     
  8. Seeking

    Thread Starter New Member

    Mar 8, 2013
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    0
    I had one cap char and want to replace the one. It was working, but began to fail. It's about 1/10 inch wide. I'll pick up some 100v tantalum and give that a try. I'm not out much if it ends up being something else. I have just seen plenty of things that a single Cap swap fixed over the years. Figured it was worth a try here.

    Thanks for the assist!
     
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