Trouble finding the correct capacitor level

Discussion in 'The Projects Forum' started by Ashton Ellison, Nov 19, 2015.

  1. Ashton Ellison

    Thread Starter New Member

    Nov 17, 2015
    So I'm still fairly new to all of this, but as I'm gathering all my parts together I can't find the right capacitors. The ones in particular are the 1000uF and 5uF capacitors from the amplifier. When I try searching for the 1000uF capacitors the only ones that come up are electrolytic. Can these be subbed?

    Also, I cannot find any 5uF capacitors besides the bottom image, which is listed at a ceiling fan motor capacitor, and obviously way too big for my board. Can this be subbed for a 10uF capacitor?
  2. AnalogKid

    AAC Fanatic!

    Aug 1, 2013
    Both the 5 uF and 1000 uF almost always are aluminum electrolytic in this application. For the 1000 there is no other choice, and for the 5 uF anything else is either huge, expensive, or both. The 5 uF can be subbed with 4.7 uF or 10 uF. Figure out the average DC voltage level across each cap and get one rated for at least twice as much. For example, if the amp is running on 16 V then its output is probably sitting at around 8 Vdc and the speaker is tied to GND, so a 16 V cap would be ok, 25 V would be better.

  3. ian field

    AAC Fanatic!

    Oct 27, 2012
    You won't find many 1000uF capacitors that *ARENT* electrolytic.

    The nearest preferred value to 5uF is 4.7uF - it can be electrolytic, but a foil type probably won't be all that huge. Multilayer ceramic chip capacitors can be pretty tiny.
  4. #12


    Nov 30, 2010
    The 1000 uf capacitor sets the low frequency pole of an 8 ohm speaker at 20 Hz like this:
    F = 1/(2 Pi C R[of the speaker])

    Almost always an aluminum electrolytic capacitor, but you can see the size (in microfarads) is negotiable.
    It takes a pretty good speaker to present 20Hz to your ears, so that size capacitor might be a bit much.;)