capacitor identification.

Discussion in 'Electronics Resources' started by DenisM, Aug 27, 2014.

  1. DenisM

    Thread Starter New Member

    Apr 23, 2012
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    Capacitor value ?
    Hi,

    Can anybody say what the value of this capacitor is ?

    I think disc ceramic 4.1 nanofarad ?

    3 Bands Yellow Black Red

    Maybe 41 * 100 = 4100 picofarad = 4.1 nano ?

    http://www.photobox.ie/album/2742761241
     
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
    5,450
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    If it follows the "modern" convention it is 4.1 x 10^2 = 4.1 x 100 = 410pF
     
  3. DenisM

    Thread Starter New Member

    Apr 23, 2012
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    It dates from the early eighties.
    Is that modern ? :)

    DenisM
     
  4. ericgibbs

    AAC Fanatic!

    Jan 29, 2010
    2,500
    380
    hi D,
    It looks more like Brown than Red to me.??
    Which part of the circuit is it from.?

    As a colour check I have added a Brown and Red bar to your image

    E
     
  5. DenisM

    Thread Starter New Member

    Apr 23, 2012
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    You know - It could be brown !

    It sits from pin1 (Vcc) of a TBA810S to ground.
    It's in an amplifier module from a Polish Transistor Radio - circa 1980.
    (Actually the IC is a UL1481P - obsolete) . TBA810 is an equivalent.
    This capacitor does not appear in the schematic.

    This version of the radio is Mono , with only one Amp ic. The schematic I have refers to the Stereo version. ( same pcb but only one chip).


    DenisM
     
    Last edited: Aug 27, 2014
  6. MaxHeadRoom

    Expert

    Jul 18, 2013
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    So its just a decoupling cap? If so it should not be that critical.
    Max.
     
  7. DenisM

    Thread Starter New Member

    Apr 23, 2012
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    Thanks.

    I was just looking for a complete understanding of the schematic before attempting a repair.

    Denis
     
  8. ericgibbs

    AAC Fanatic!

    Jan 29, 2010
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    Using the colours in the Bn, Bk, Yw, order would make it a 100nF, a common value for decoupling.

    E
     
  9. DenisM

    Thread Starter New Member

    Apr 23, 2012
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    Ah!

    I was reading the bands the other way !

    It reads a value of 82 n on my meter.

    I guess the tolerance on those would accommodate that value.

    reading 82 when the bands told me 4100 was just too illogical for me !

    Thanks to all.

    Denis
     
  10. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    According to this source, bands are read from the top edge toward the pins:

    Capture.PNG

    As for color, we all seem to agree the first color is yellow. The second looked blue, but could be black, and the third looked more red than brown on my monitor.

    John

    Edit: Source: http://www.electronics-tutorials.ws/capacitor/cap_5.html
     
    Last edited: Aug 27, 2014
  11. DenisM

    Thread Starter New Member

    Apr 23, 2012
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    I can see why marking with numbers/letters is the better way :)

    D.
     
  12. BR-549

    Well-Known Member

    Sep 22, 2013
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    Can you measure the capacitance?
     
  13. DenisM

    Thread Starter New Member

    Apr 23, 2012
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    It reads about 82 nF as I said above.

    I've since compared it with other capacitors of the same properties else where in the radio and by checking the schematic, I realise that the bands *are* read from the bottom up. thus it is (Brown or Red) , Black, Yellow = 1 , 0, + 0000 = 100nF . (or 200 if Red)

    I guess 80 nf is close enough to 100 :)

    Thanks for all your help/comments.

    Denis
     
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