Capacitors values

Discussion in 'General Electronics Chat' started by erich_7719, Jan 21, 2010.

  1. erich_7719

    Thread Starter Active Member

    Oct 14, 2009
    92
    7
    Just a general question...

    I you had to make a list of the most commonly used values of Electrolytic and ceramic disc capacitors, what would those values be? And what general purpose would they serve? Ie…1pF decoupling.

    Thank you in advance
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,645
    2,344
  3. erich_7719

    Thread Starter Active Member

    Oct 14, 2009
    92
    7
    I guess that I was looking more for a preference of which values get used the most. I do not want to buy a bunch of caps I may never use but would rather buy those that would have a higher likeliness of being used, for general experimentation.
     
  4. Bernard

    AAC Fanatic!

    Aug 7, 2008
    4,170
    395
    A lot depends on type of electronics that you are interested in, digital, audio, rf,hi V. For digital & GP , all in uF. .01, .1, .5, 1, 4.7, 10, 20, 100, 1000; all @ 25V.
     
  5. erich_7719

    Thread Starter Active Member

    Oct 14, 2009
    92
    7
    Digital and GP works for me, Thank you.
     
  6. cumesoftware

    Senior Member

    Apr 27, 2007
    1,330
    10
    For capacitors, you should use some value inside the E6 range (1.0, 1.5, 2.2, 3.3, 4.7 and 6.8), since those values are more common to be found, and preferred by retailers (most capacitors sold out there have 10% tolerance). As for decoupling (digital and analog ICs) I normally prefer 100nF polyester capacitors (one per IC). On power amplifiers, I normally use a 100uF electrolytic capacitor paralleled with a 100nF polyester capacitor for decoupling, unless otherwise noted (that is, if the datasheet requires a different value to be used).

    100nF is a preferred value for decoupling, but some folks prefer using something as low as 10nF, which is fine in most cases.
     
    Last edited: Jan 24, 2010
  7. erich_7719

    Thread Starter Active Member

    Oct 14, 2009
    92
    7
    Thank you both, for your advice just one last question. For the most basic power supply (either 5 or 12V), IE... transformer, couple Caps, Positive regulator, couple more caps.

    [​IMG]

    Would 1000uF electrolytic followed by a 4.7uF Disk be sufficient?
     
  8. cumesoftware

    Senior Member

    Apr 27, 2007
    1,330
    10
    A regulator usually won't require a polyester capacitor at it's input (as it is not very sensitive to fast transients), only if it is 3 inches away from the main filter capacitor (the LM78XX series requires a 330nF poly cap at the input if that is the case). And the capacitance of the main filter capacitor pretty much depends on the ripple voltage you want and the current demanded. Use the formula for a full wave rectifier:

    C = I / (2 * f * Vripple), being f the mains voltage frequency

    At the regulator output, simply use a 100nF poly cap. The electrolytic is not needed.
     
  9. lmartinez

    Active Member

    Mar 8, 2009
    224
    6
    All of the values available in the market are popular. It all depends on the type of application.
     
  10. erich_7719

    Thread Starter Active Member

    Oct 14, 2009
    92
    7
    Thank you all for you input.
     
  11. loosewire

    AAC Fanatic!

    Apr 25, 2008
    1,584
    435
    Take the good advise you get here on A.C.C. ,if your go to a capacitor
    site you want see anything that you reconize.They show you ball point
    pen tip among small metal shapes that you would not have a clue what
    you are looking at.They want you to know the part no- or value.
     
Loading...