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Small size 2.2µF , 400 volt Capacitors

  1. Feb 14, 2014 #1
    Hello Guys, I am looking for an alternative for the big size electrolytic capacitors. Can you suggest me any alternatives or solutions. I need a small solution with dimensions of 2.2μ, and 440 volt.

    Thanks in Advance,
     
  2. jcsd
  3. Feb 14, 2014 #2

    berkeman

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    Welcome to the PF.

    Does the cap need to be non-polar? Or can it be polarized? What is the ripple current (magnitude and frequency)? What is the application?
     
  4. Feb 14, 2014 #3
    Thanks Berkeman, The cap would be used in a rectifier circuit that transforms from 110 Ac to 5 volt DC , I am not an electrical engineer, so I don't know if it should be polarized or not (but I think yes).
     
  5. Feb 14, 2014 #4

    berkeman

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    Why does the cap need to have a voltage rating of 440V if it is just smoothing the 5V output of the transformer?
     
  6. Feb 14, 2014 #5
    It should be for a mobile charger, I opened a smasung charger, and an charger apple, and both had a 400v, capacitor, What do you think ?
     
  7. Feb 14, 2014 #6

    berkeman

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    Well, if they are rectifying the AC Mains input, and then using a DC-DC converter to make the 5V, then I can see a high-voltage polar cap being needed. In your initial post, I assumed that this was a traditional transformer followed by the rectifier and smoothing cap.

    Can you post a picture?
     
  8. Feb 14, 2014 #7
    yes of course! 1608525_10202346250830315_1286911159_n.jpg

    1615029_10202346370833315_704095345_n.jpg
     
  9. Feb 14, 2014 #8

    berkeman

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    Yeah, that's the AC Mains input storage cap after the half-wave rectifying diode. You won't be able to reduce its size by much from the polar electrolytic that is being used already. For what reason are you looking for a smaller alternative?
     
  10. Feb 14, 2014 #9
    I am creating a multi-tasking system with led lights, speakers and charging, and system for a course at the university, and I will use that system, I am kinda copying it. so by that, I understand that no titanium capacitors, or SMT capacitors ? I dont want to do the circuit by my hand, but only a plan of how it can be done, and what it needs
     
  11. Feb 14, 2014 #10

    berkeman

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    I think you mean tantalum instead of titanium... :smile:

    No, that's pretty much the size of it. If you are going to show connection to the AC Mains in your project drawing, be sure to include a fuse in line with the Hot lead, and a power switch in line with the Hot lead. Do not actually build anything that involves AC Mains high voltage connections, until you know a lot more about electronics. It can be very dangerous to work with (shock and fire hazard).
     
  12. Feb 14, 2014 #11
    Yes, I definitely meant that :P. Thank a lot for your advice, I am not going to do that. So you think there's no other systems can be used with small size to do the same job of transforming 110v AC into a 5v DC ? Plus, a polarized capacitor should be used , right ?
     
  13. Feb 14, 2014 #12

    berkeman

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    I don't think you can reduce the size of that cap much, especially not knowing what other specs are important for it (like ESR, ripple current, etc.).

    A polar cap is usually smaller than a non-polar cap in physical size (for large value capacitors like this one). So if you are dealing with a DC voltage and want smallest/cheapest, yes you use a polar capacitor.
     
  14. Feb 14, 2014 #13
    Aha, I see your point. I googled some stuff and I found this, what do you think ? they seem very small in size, and with about 500 volt, and 2.2uf.
    View attachment vjcommercialseries.pdf
     
  15. Feb 14, 2014 #14

    davenn

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    No you cant use that cap as the main smoothing cap after the rectifier
    for a start it's not a polarised cap
    you have no choice but to use what has already been suggested and what is in your photos

    cheers
    Dave
     
  16. Feb 15, 2014 #15
    For electronic components, try using www.digikey.com for a big part reference. It has a very comprehensive inventory and you should find the part you want there.
     
  17. Feb 15, 2014 #16
    Thanks a lot guys.
    How can I know the circuit design of this pcb? or get anything close to it ? any ideas please ?
     
  18. Feb 15, 2014 #17

    davenn

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    reverse engineer it
    draw the circuit out, its a very basic circuit :smile:
    The only thing you wont be sure of without some serious effort is the number of turns on the transformer windings. Everythuing else is straight forward

    Dave
     
  19. Feb 15, 2014 #18

    meBigGuy

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    @davenn

    Why can't he replace the 2.2uF 400V electrolytic with a 2.2uF 500V Ceramic? You said "because it is not polarized, which I don't get.
     
  20. Feb 15, 2014 #19

    berkeman

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    You don't need to use this exact circuit, since you say that you are just writing a schematic to do similar things. Use Google Images to look for AC Mains to 5V switching power supplies, and use one of them.
     
  21. Feb 15, 2014 #20

    berkeman

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    Interesting parts. Can you summarize the difference in physical size between the two parts? A ceramic non-polar capacitor will generally have superior performance compated to an electrolitic capacitor. It will also generally be more expensive...
     
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