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How to find a particular capacitor?

Discussion in 'Datasheets, Manuals or Parts' started by fractal5, Sep 22, 2015.

  1. fractal5

    fractal5 New Member

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    I need a 1 uF 5 volt capacitor. It has to have a size that is suitable for through-hole soldering. I find it quite hard to just browse online stores such as RS Components for this. There are so many types of capacitors that I don't even know what category I should be looking at.
     
  2. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    There isn't enough info. Axial/Radial, electrolytic, tantalum, metalized polyester etc. What pitch are you looking for? Voltage? Application?

    Do you have a pic of the original, if this is a replacement?
     
  3. fractal5

    fractal5 New Member

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    This is my problem, I don't know. :)

    http://www.z80.info/z80test0.htm

    I'm trying to build this circuit, just for fun.
     
  4. dave

    Dave New Member

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  5. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    The 100nf to 1 uf cap is a bypass cap. Typically these are ceramic, but could be tantalum or could even be a parallel combination of the two. I'd probably use a tantalum electrolytic there. The value isn't critical. Capacitor values ad when in parallal, so a 0.1 || 0.47 is equivalent to a 0.57 capacitor. Tantalum capacitors are polarized - pay attention to polarity. Ceramic generally isn't. Metalized Polyester aren't polarized, but sometimes it matters .

    The 1 uf capacitor should be a metalized polyester with a better tolerance.

    Any voltage greater than 2x the supply will work within reason.

    I only got one decent hit at digikey: http://www.digikey.com/product-detail/en/168105J50G-F/338-3265-ND
    Film cap, under 50 V, 1uf, +-5% tolerance (timing circuit). Filling in your country would help me.
     
  6. fractal5

    fractal5 New Member

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    Thanks for your suggestion. I thought the Z80 uses 5 volts, will it still work with a 50 volt capacitor?

    I'm from Norway.
     
  7. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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  8. fractal5

    fractal5 New Member

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    I don't shop at RS, I don't usually buy components at all, except the odd grab bag and such from eBay.

    As for RS, it costs me 41 USD to get one of these capacitors (RS require a minimum purchase of 10, and the shipping is costly).
    As for Farnell, they only sell their products to businesses (they require a Business Registration Number when creating an account).
     
  9. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    How about: http://no.mouser.com/Passive-Compon...Z1yznbzr&Keyword=polyester+capacitors&FS=True

    Lots of choices.

    I think this http://uk.farnell.com/ is your farnell link. I'm surprised they require a business registration. My counterpart in the US www.newark.com doesn't. newark.com, farnell.com and element14 are all the same company. Some places require company names and I just put my name there. No issues.

    You may have the funky VAT stuff. The tax on a tax on a tax. The taxID or whatever is usually necessary if your going to resell it. I'm also lucky, I'm in a state in the US with no sales tax. GENERALLY in the US, unless the company has a presence in the shipping destination AND the shipping destination has a tax, sales tax isn't collected.

    I physically bought audio stuff in a nearby state that had a tax and shipped home or the same store in my state that had no tax and so I didn't pay any. Automobiles are wierd (simplified), but people can buy over the state line (my tax free state) and not pay sales tax because we don't have any.

    There are companies that only do business to business. Once, I used my work address for the already paid invoice and that was fine. I was allowed to ship home.
     
  10. fractal5

    fractal5 New Member

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    Thanks a lot for your help, it is a shame that I have to pay $17 in shipping for just getting a single small capacitor. Do I even need this particular capacitor? Can I use something else? I have a bunch of capacitors laying around, do you happen to know what range would be applicable for that Z80 circuit and I wouldn't even have to order a new one.
     
  11. atferrari

    atferrari Well-Known Member

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    Don't you have two .47uF caps around? Put them in parallel and try!

    The worst could be the circuit not working but most probably it will. Give a try instead of hesitaing that much for a simple cap. There is always a chance for things to fail or not work at all. Go and try.
     
  12. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    It appears they want it visble, so they chose 28 Hz.

    You can try any R from about 1K to 1 Meg ohm where the product of R and C remain proximately the same. K= 68,000 * 1e-6

    (1) xt=x1+x2+....Xn

    (2) 1/xt=1/x1+1/x2+...1/Xn

    I used x here for a reason:
    Resistors in series follow rule 1, in parallel rule 2
    Capacitors in series follow rule 2, in parallel rule 1 (backwards)

    The special case 1/x rule says if two identical values are used they half. 8 ohms || 8 ohms is 4 ohms and that the value will always be smaller than the smallest value.

    Just use a non-polarized capacitor. Ceramic or polyester. An electrolytic might work.

    1 uf is where manufacturers use electrolytics because of cost, particularly in audio coupling, but polyester is more appropriate. Electrolytics have low tolerances like +80, -10%.

    Paralleling and series will affect tolerances.
     
  13. Les Jones

    Les Jones Well-Known Member

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