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Exactly how evil are Capacitors?

Discussion in 'General Electronics Discussion' started by blaablaaguy, Dec 6, 2015.

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  1. blaablaaguy

    blaablaaguy

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    Exactly how dangerous are Capacitors? Its just that their awesome but im afraid of getting electrocuted or killing myself. ):
     
  2. Martaine2005

    Martaine2005

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    That is how awsome they are! IF they are high voltage ones :D



    Martin
     
    Last edited by a moderator: Dec 7, 2015
  3. blaablaaguy

    blaablaaguy

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    So its safe for a completely irresponsible noob to mess around with them? And you wouldnt mind explaining what a flashover is?
     
  4. Martaine2005

    Martaine2005

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    TBH, most circuits (today) have a bleed resistor.
    But if it doesn't, that's when you get zapped!!
    And they can KILL!!!

    Don't play with something you are unfamiliar with! Would you pet a Hyena? Expect to get bitten!!

    Martin
     
    Tha fios agaibh and blaablaaguy like this.
  5. BobK

    BobK

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    They are only as dangerous as the voltage they charged to. Under 30V, not dangerous at all.

    Bob
     
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  6. hevans1944

    hevans1944 Hop - AC8NS

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    [mod deleted irrelevant stuff]


    When you need a capacitor there are no workarounds. Learn some more about electricity and the properties of electrical components so you won't be an "irresponsible noob" anymore. All of us here had to start somewhere. No one I know of was born with an innate knowledge of electricity. And, as @Minder said, I also know of no one who has been killed by a charged capacitor. That doesn't mean it can't happen. There have been plenty of injuries, some minor and some not so minor, from charged capacitors.

    Learn and be safe. It's a fun hobby, and for someone with proper training and experience, a well-paying vocation. Come back here often when you have a problem to solve or a question that needs answering and you can't, with due diligence, solve it or find the answer yourself. Just don't expect us to do everything for you.
     
    Last edited by a moderator: Dec 7, 2015
    Martaine2005 likes this.
  7. davenn

    davenn Moderator

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    OK guys, I have done a major cleanout in here
    Everyone has gone off on a wild tangent of assumptions without specifically asking the OP
    what the query was all about

    SO, a fresh start
    where does this query stem from ? is it just a learning thing or do you have a project in mind ?

    3 hours later ......... damn got tied up at work and forgot to hit post

    AGAIN keep on topic once we find out what it is wait for the OP to respond to my Q's
     
  8. dorke

    dorke

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    Jun 20, 2015
    Disagree!
    Low voltage can't electrify a person but,
    in some cases the current can cause very serious injures.
    Have you ever seen a thin wire short out a car battery(which is actually a capacitor charged to "only" 12V)?
    The current will melt the insulation and burn the wire.
    If there is a person holding that wire with his bare hands...
    he will be branded worse than cattle with a branding iron...:eek:


    Have you ever seen a low voltage(5V circuit) electrolytic or ceramic capacitor
    blow-up?
    That can blind and destroy a face of person working/measuring the board the cap is in...:eek:

    To sum up,
    Energy(charge), stored in capacitors may be very dangerous ,
    low or high voltage!
    That doesn't mean we shouldn't use them,quit the contrary .

    some precaution rules:
    1.Always discharge big value capacitors properly and with great care.
    2.Same for High voltage ones.
    3.Make sure you don't put your face too close to capacitors under voltage(low voltage as well).

    And here is an under 3V demolition video for you,enjoy ;)
     
    Last edited: Dec 7, 2015
  9. blaablaaguy

    blaablaaguy

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    I suppose its just for learning purposes. I might want to use them later on but for now I haven't got a project in mind.
     
  10. cjdelphi

    cjdelphi

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    Capacitors can be dangerous.... high voltage ones 100+ can kill you if the cap discharges through your body ..

    Under 50v or so, caps with enough storage capacity can burn you..

    I have a few 350F 2.5v caps I'm still undecided on what to do with yet, charging them safely is the only thing putting me off (an atx power supply is the only thing up to the job if I can control current surges, maybe an opamp?.. anyways)

    Caps are safe if not safer than regular batteries, their low energy storage and low internal resistance keeps things cool compared to say a lithium battery.
     
  11. cjdelphi

    cjdelphi

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    Oh they're safer if 1. You don't charge to a higher voltage than rated, Eg 9v cap will die possibly explode if you supply say 15v, and don't wire them up back to front unless you enjoy fire crackers going off...
     
  12. ecollen

    ecollen

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    Blaablaa guy, if you haven't yet, be sure to take a look at this video link of dorke. Those things can be lethal unless you're 100% sure what you're doing. Please don't take any chances.
     
  13. Martaine2005

    Martaine2005

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    That's because we are psychic!:D
    We instinctively knew that he wanted to play, like in the videos all over Youtube!.

    Martin
     
    hevans1944, Harald Kapp and ecollen like this.
  14. blaablaaguy

    blaablaaguy

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    Exploding, fireworks, melting stuff... KEEP THOSE THINGS AWAY FROM ME!
     
    ecollen and Martaine2005 like this.
  15. Martaine2005

    Martaine2005

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    May 12, 2015
    Now, those are wise words...:)
    You have finally seen the light !... Well, on video only.:D
    Just stay safe my friend and play safe!

    [​IMG]
     
    ecollen likes this.
  16. cjdelphi

    cjdelphi

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    Cars can blow up too! Do you avoid them as well? Lol
     
  17. ecollen

    ecollen

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    Preferably!
     
  18. ecollen

    ecollen

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    The interesting question now is, how do you discharge a capacitor safely, bearing in mind that in many cases you don't know how much power is stored in the thing
     
    Last edited: Dec 8, 2015
  19. cjdelphi

    cjdelphi

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    Really, it /can/ kill you, not likely unless you're stupid and simply asking for it lol

    Someone in the Army or Navy? Was learning Electronics and his tutor said pretty much the same here ... low voltage being safe, and one of the exercises was to measure skin resistance from a multimeter running off a 9v battery..

    Well being a tough (insert profession) guy he wanted to measure how much resistance under the skin!

    He never really found out, the internal body has a lot lower resistance than skin even wet skin, as a result there was enough current to stop his heart! He died from a 9v battery...[/QUOTE]
     
  20. cjdelphi

    cjdelphi

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    Oct 26, 2011
    Well, it's called a resistor :)

    Without a multimeter, attach a 1k resistor to both terminals then go bed!

    1 - 5v cap 1k resistor
    5 - 18v cap 5-10k

    For 240vac, nor sure not done the calculation, but probably in the 20k range a 1w or so..

    240/0.02 (volts/amps = resistor bleed value) just don't exceed wattage
     
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