Page 1 of 2 12 LastLast
Results 1 to 10 of 13

Thread: Is leakage current of capacitor important?

  1. #1
    Join Date
    Aug 2018
    Location
    Korea
    Posts
    295
    Thanks Thanks Given 
    144
    Thanks Thanks Received 
    18
    Thanked in
    13 Posts

    Default Is leakage current of capacitor important?

    Is leakage current of capacitor important in psu? For each primary and secondary...

  2. #2
    Join Date
    Oct 2006
    Location
    jonnyGURU forums, of course!
    Posts
    16,185
    Thanks Thanks Given 
    544
    Thanks Thanks Received 
    302
    Thanked in
    218 Posts

    Default

    Umm.. Yeah.

    You kind of what as little as possible.

  3. #3
    Join Date
    Oct 2017
    Location
    Grand Junction, CO
    Posts
    2,020
    Thanks Thanks Given 
    114
    Thanks Thanks Received 
    62
    Thanked in
    55 Posts

    Default

    Quote Originally Posted by rgbodosk View Post
    Is leakage current of capacitor important in psu? For each primary and secondary...

    When I replace secondary capacitors it is one thing that I don't worry about.
    Last edited by ashiekh; 3 Weeks Ago at 05:57 PM.

  4. #4
    Join Date
    Oct 2006
    Location
    jonnyGURU forums, of course!
    Posts
    16,185
    Thanks Thanks Given 
    544
    Thanks Thanks Received 
    302
    Thanked in
    218 Posts

  5. #5
    Join Date
    Oct 2017
    Location
    Grand Junction, CO
    Posts
    2,020
    Thanks Thanks Given 
    114
    Thanks Thanks Received 
    62
    Thanked in
    55 Posts

    Default

    The capacitors I replace are for smoothing, not precision; I assumed the original poster was referring to such large electrolytics.

    After capacity, voltage, temperature rating and physical size I look for low ESR and long life.
    Last edited by ashiekh; 3 Weeks Ago at 06:01 PM.

  6. #6
    Join Date
    Aug 2018
    Location
    Korea
    Posts
    295
    Thanks Thanks Given 
    144
    Thanks Thanks Received 
    18
    Thanked in
    13 Posts

    Default

    Do I need to really consider that when choosing PSU? or it's just minor-ish thing..?

  7. #7
    Join Date
    Oct 2017
    Location
    Grand Junction, CO
    Posts
    2,020
    Thanks Thanks Given 
    114
    Thanks Thanks Received 
    62
    Thanked in
    55 Posts

    Default

    Have you ever read a power supply review that was concerned about leakage current in the capacitors? if not, then since they don't worry, maybe you don't need to.

    Says he nervously in anticipation of a link from the Guru showing a review with just such a concern...

  8. #8
    Join Date
    Oct 2006
    Location
    jonnyGURU forums, of course!
    Posts
    16,185
    Thanks Thanks Given 
    544
    Thanks Thanks Received 
    302
    Thanked in
    218 Posts

    Default

    Reviewer's don't look at it because it's a footnote spec in the data sheet.

    Heck... reviewers don't even do the cap life calculation to see if the caps are even suitable for the application. They only care if they're Japanese.

    I wouldn't worry about it. They'd have to be pretty cheap caps to have any kind of detrimental leakage current.

    Your original question was "is it important", to which my answer is "yes".

  9. The Following User Says Thank You to Jon Gerow For This Useful Post:

    rgbodosk (3 Weeks Ago)

  10. #9
    Join Date
    Oct 2017
    Location
    Grand Junction, CO
    Posts
    2,020
    Thanks Thanks Given 
    114
    Thanks Thanks Received 
    62
    Thanked in
    55 Posts

    Default

    One adds a bleed resistor across the primary capacitor for safety, i.e. one has greatly increased the leakage current intentionally; so I would argue that in the context of a power supply leakage current is of no great concern. Now for medical grade power supplies leakage to ground is an issue.

    I am now beyond my limitations and very much aware of it, so please don't get mad with me; I'm just learning.

  11. #10
    Join Date
    Oct 2006
    Location
    jonnyGURU forums, of course!
    Posts
    16,185
    Thanks Thanks Given 
    544
    Thanks Thanks Received 
    302
    Thanked in
    218 Posts

    Default

    Quote Originally Posted by ashiekh View Post
    One adds a bleed resistor across the primary capacitor for safety, i.e. one has greatly increased the leakage current intentionally; so I would argue that in the context of a power supply leakage current is of no great concern. Now for medical grade power supplies leakage to ground is an issue.

    I am now beyond my limitations and very much aware of it, so please don't get mad with me; I'm just learning.
    Leakage current of a capacitor is not in direct proportion to the leak current measured of a power supply. Don't confuse the two.

    And yes, there has to be bleeder resistors in order to meet most safety certifications in the world.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •