What are 500 hr / 1000 hr / 2000 hr capacitors used for?

Discussion in 'General Electronics Chat' started by DMahalko, Jun 27, 2012.

  1. DMahalko

    Thread Starter Senior Member

    Oct 5, 2008
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    What is the purpose of a capacitor with such a low stability rating?

    Example parts lookup:
    http://www.newark.com/jsp/search/browse.jsp?N=422+201222+810103540+810085441+810045637+810095263&No=0&getResults=true&appliedparametrics=true&locale=en_US&divisionLocale=en_US&catalogId=&skipManufacturer=false&skipParametricAttributeId=&prevNValues=422+201222&mm=1001090||,&filtersHidden=false&appliedHidden=false&autoApply=false&originalQueryURL=%2Fjsp%2Fsearch%2Fbrowse.jsp%3FN%3D422%2B201222%26No%3D0%26getResults%3Dtrue%26appliedparametrics%3Dtrue%26locale%3Den_US%26divisionLocale%3Den_US%26catalogId%3D%26skipManufacturer%3Dfalse%26skipParametricAttributeId%3D%26prevNValues%3D422%2B201222


    Is this for a short term design project where the device isn't expected to be used for very long anyway?

    Maybe for bomb timers and IED manufacturing? ;)

    Is this how the makers of poor grade capacitors that fail quickly, manage to sell off their stock in an honest manner?



    I can't really fathom why you'd want to use a capacitor with a rated stable lifespan of... 500hr / 21 days or even 3000hr / 125 days. How does it keep from going bad just sitting at the part distributor's warehouse?

    I assume the issue is really about "temperature excursions" and that the capacitor will remain stable indefinitely if the specified high temperatures are avoided.

    Though 500 hrs at 55 C makes little sense. You can hit those temps just leaving the parts bag in your car on a hot summer day.



    What would be considered a reasonable minimum hobbyist-grade capacitor life / temperature rating, for a project that should remain stable and functional for say 10-20 years?
     
  2. strantor

    AAC Fanatic!

    Oct 3, 2010
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    so you can work planned obsolesence into your designs
     
  3. DMahalko

    Thread Starter Senior Member

    Oct 5, 2008
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    Whether or not your response is a joke, I agree that you are probably correct.
     
  4. strantor

    AAC Fanatic!

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    I was jovial, but not joking.
     
  5. BreadCrum6

    New Member

    Aug 17, 2011
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    Thought so too. One of those " Wait, was that a joke" moments.
     
  6. strantor

    AAC Fanatic!

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    It's no secret, they do it. Look at the price of these low life caps and compare it to the price of higher life caps of the same rating. Nearly no price difference.

    100uF 500 hour caps
    100uF 10,000 hour caps

    I'm seeing plenty of 10,000hr caps that are cheaper than a lot of the 500 hour caps. There are a few 500hr caps that are really really cheap, but I the majority are around the same price as the 10,000hr ones. Why would you choose the 500hr caps over the 10,000hr ones if they are nearly the same price? Because if you put 10,000hr caps in there, it's a lot more likely to never quit working and you're a lot less likely to ever sell another unit to that customer again. sad but true.
     
  7. absf

    Senior Member

    Dec 29, 2010
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    I remember there are disposable cameras where they were used once and thrown away. They dont need to last 500 hours. Did they have any flash light built-in?

    And what about those electronic toys for children? I dont think they are designed to last for more than 10,000 hours. Not forgetting the christmas card that has sound chip inside.

    Allen
     
  8. WBahn

    Moderator

    Mar 31, 2012
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    Are you comparing apples to apples? There's a wide variety of caps in both of those lists? It's not at all surprising that a 500hr 200V rated cap is more expensive than a 10khr 25V rated cap.

    I picked the top one from the 500hr list and then found the closest equivalent in the 10khr list. For quantities of 1000, the prices were $1.20/ea and $1.65/ea. That is a HUGE price difference. Imagine you have a consumer product that you are selling 10 million units of a year. You do absolutely nothing except make this change. You've just added $4.5 million to the company's bottom line. There are four of those caps in that product? Now it's $18 million. You have ten products that each have comparable sales and contain the same number of these caps? Now it's $180 million a year.

    So the motive to use the cheaper cap is extremely strong and doesn't have to have anything to do with planned obsolescence. You do need to way the pros against the cons of using the cheaper caps and one of those is risk of market share. I know when I buy something and it lasts a week, I don't just buy another one of the same kind from the same place -- I never buy that brand again, not for many, many years any way.

    That's certainly not to say that all such decisions are made with the appropriate weights given to each factor or that short-sighted thinking can't play a disproportionate role in the process. Both of those are very real factors that come into play.
     
  9. strantor

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    WBahn consider yourself a minority. I perceive the majority to be lemmings, and I believe they would go out and buy the exact same thing when it breaks; in fact, I've seen it more times than I care to think about. Makes me sick when consumers (who I care about) play into the hands of those who make crap. Attention Walmart shoppers, special on aisle five; two appliances for the price of one, and trust me, you'll need both of them.
     
  10. DMahalko

    Thread Starter Senior Member

    Oct 5, 2008
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    It just depends on the obsolescence you've learned to accept vs the one you haven't.


    What are the specific physical reasons that fluorescent lamps eventually fail? (Oh, I should save this discussion for another thread. Resist. Urge. To. Post. Here.) :D
     
  11. strantor

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    I don't know much about flourescents, but it sounds like it's a hot button item?

    I think household printers are a big planned obsolescence thing.

    I just had a keurig coffee pot fall on it's face after 6 months. Tried to take it apart and fix it, and its assembled in never-never fashion, not meant to be serviced. By the time I got it apart there wasn't anything left to fix. I trashed it and vowed never to buy another one (on principle) despite the 200 k-cups in my pantry. So my mother bought me a new one.
     
  12. bountyhunter

    Well-Known Member

    Sep 7, 2009
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    Or PC hardware...... got a shock for you, most aluminum electrolytics (which populate the power supplies of most consumer products) have expected life spans of a few thousand hours.

    Why do you think you have to buy a new computer every three years.
     
  13. atferrari

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    Washing machines whose drum and associated parts cannot be disassembled precluding any repair. They exist for long time now.
     
  14. Markd77

    Senior Member

    Sep 7, 2009
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    I'm guessing it's the capacitor. I've taken a few brands of failed bulb apart and they all have bulging capacitor syndrome. This one is a Phillips.
    This is apparently a high quality capacitor, the Aishi CD11GA 105C 8000h, 130C 2000h
    [​IMG]
     
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  15. shortbus

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