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novice question

Discussion in 'Electronic Basics' started by Andy C, Mar 6, 2007.

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  1. Andy C

    Andy C Guest

    hi all,
    i'm building a small electronics project which was bought in kit form...
    bear with me i'm a beginner ;)
    everything is soldered onto the board except for a few components i'm not
    sure about...
    there are places on the board left for 4x 1microF capacitors (the tiny ones
    which aren't polarity sensitive- not sure the proper name!) i have 4x
    capacitors with just the number "105" on them left over- do you think they
    have sent the wrong capacitors or is "105" actually a 1microF capacitor?

    there are also 9 places on the board left for 9x 100nF capacitors... i have
    9x capacitors with the number "104" left over - are these the wrong ones?

    many thanks!!
  2. Puckdropper

    Puckdropper Guest

    Capacitors are labeled funny. (To me, at least.) What I usually do is
    search for "104 capacitor" via Google, and often I get a page with the
    value of the capacitor. If you're doing a lot of work with capacitors,
    you'll want to learn the codes. If it's just a "now and then" thing,
    there's no need.

  3. Yes, the 105 means a 10 followed by 5 zeroes or 1,000,000pF (pico-Farads)
    which is exactly equal to 1uF (micro-Farad), or even 1,000nF (nano-Farads)
    Those are the correct caps. 104 is 10 followed by 4 zeroes or 100,000pF
    which is the same has 100nF and .1uF. Does that help?

    In descending order it goes Farads(F), mill-Farads(mF), micro-Farads(uF),
    nano-Farads(nF), and pico-Farads(pF).
  4. Chris

    Chris Guest

    Hi, Andy. You're doing fine -- your caps marked 105 are 1uF, and the
    104s are 0.1uF or 100nF caps. You can complete your kit with the
    parts you have.

    This is a common newbie question. For many good answers to your
    question, go to Google Groups s.e.b. and search in that group for the
    phrase capacitor codes (no quotes).

    Congratulations on getting the parts right. That's not the easiest
    thing for a newbie. Hope everything works OK. If not, feel free to
    post again -- be sure to mention the kit manufacturer and kit number
    -- it helps.

  5. Andy C

    Andy C Guest

    What I usually do is
    thank you! don't know why i didn't think of that !!
  6. Ceramic capacitors are often marked with their values in picofarads,
    using a three digit code: two digits plus a multiplier.

    Your "105" capacitor is 1, 0, 00000 pF, or 1,000,000 pF which equals 1
    uF. the "104" parts are 0.1 uF or 100 nF or 100,000 pF.

    Peter Bennett, VE7CEI Vancouver BC, Canada
    peterbb4 (at)
    new newsgroup users info :
    GPS and NMEA info:
    Vancouver Power Squadron:
  7. Use of milli-Farads can be confusing and/or hazardous.

    In ancient times, before the Greek alphabet was invented, we used "mF"
    or "MF" to mean microfarad (and mmf for micro-micro farad, now called
    picofarad), so using mF for millifarad will confuse many older techs,
    and mislead newer techs looking at old schematics.

    Peter Bennett, VE7CEI Vancouver BC, Canada
    peterbb4 (at)
    new newsgroup users info :
    GPS and NMEA info:
    Vancouver Power Squadron:
  8. You're right, and I just saw a schematic using mF for uF, why oh why.

    Have a look at Fig. 2 and Fig. 3. As you can see it all looks very simple.
    If a capacitor is marked like this 105, it just means 10+5 zeros = 10 +
    00000 = 1.000.000pF = 1000 nF = 1 µF. And that's exactly the way you write
    it too. Value is in pF (PicoFarads). The letters added to the value is the
    tolerance and in some cases a second letter is the temperature coefficient
    mostly only used in military applications, so basically industrial stuff.
  10. Rich Grise

    Rich Grise Guest

    Those are the right caps. The numbers are just the standard color code
    printed in numbers instead of colors. So, for the 105, that's one '1',
    one '0', and five more '0's, or 1,000,000 pf, which is 1 uF. Same with
    the 104: 1 0 0000, which is 100 nf == 0.1 uF == 100,000 pf.

    You might try googling on "color code" or "resistor color code".

    Have Fun!
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