What is the value & voltage ratings of this capacitor

• What is the value & voltage ratings of this capacitor
  Posted by Vindhyachal.takniki on 06 Feb, 2017 05:10
• What is the value & voltage ratings of this capacitor
  
  1. Attached find a pic of a board. This is capacitive supply board & two capacitor in series are used. The boards works upto 440V.
  
  2. What is capacitance & voltage rating of this capacitor.
  Is cap = 550uF
  & voltage rating=??
  
  3. H684K      C
  550MFF4
  
  Not sure if its C in first line end.

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• #1 Reply
  Posted by David Hess on 06 Feb, 2017 05:26
• 684K means 68 * 10^4 picofarads or 680,000 picofarads or 680 nanofarads or 0.68 microfarads.  I think 550 is the DC voltage rating.
  
• #2 Reply
  Posted by tautech on 06 Feb, 2017 05:36
• Quote from: David Hess on 06 Feb, 2017 05:26

  684K means 68 * 10^4 picofarads or 680,000 picofarads or 680 nanofarads or 0.68 microfarads.  I think 550 is the DC voltage rating.
  

  The K has nothing to do with the absolute value, it is the value tolerance indicator, in this case +10%
  
  http://www.robotoid.com/appnotes/electronics-capacitor-markings.html
• #3 Reply
  Posted by Vindhyachal.takniki on 12 Feb, 2017 05:56
• Thanks for your reply.
  I have to make a capacitive supply from 440Vac to 9vdc & then regulator 7805.
  Will make & see the results. Tested using these capacitors it is working fine.
  But I will connect two 2.2uF,400V in series to be used for this since current requirement is bit more, cap as in attaced pic. SO that end capacitance is 1.1uF/800V.
  Though They are not safe since they are not X2 type. But I have seen them in so many boards, none of them had any problem due to capacitor or capacitor every busted.
  
  1. Are these two capacitor in series can withstand 440Vac. Since combined voltage value will be 800V.  In ac 440Vac peak will be = 440*(2^0.5) = 622Vac. So I think I am well within limits?
  Theoretically for 800V max ac can be = 800V/(2^0.5) = 565Vac.
  
  2. What is voltage variation in these capacitors? is it +-10%?
  3. Which fuse value should be used in this? Max ac load comes out to 150mA. So I am placing 1A fuse.
  4. What is the MOV selection criteria for this.

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• #4 Reply
  Posted by deltalight on 12 Feb, 2017 06:25
• If I read your objective correctly, you are constructing a transformerless supply where the 2.2uF 400v film cap is in series with the A/C line (220VAC?).
  If this is the case, then you may want to use a Panasonic Class X sately film caps:
  
  ECQUA (Class X) Polypropylene
  http://datasheet.octopart.com/ECQ-UAAF684K-Panasonic-datasheet-22087606.pdf
  ECQUL (Class X2) Metalized Polyester
  http://www.farnell.com/datasheets/18742.pdf
  
  
  The film structure in these caps is made in a matrix such that if it fails, it opens and doesn't short for sately reasons. Should be available from DK and Mouser.