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Diode when wet

Discussion in 'General Electronics Discussion' started by marky1993, Aug 5, 2012.

  1. marky1993

    marky1993

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    Aug 5, 2012
    Hello there... I was wondering what will happen if i let a diode get wet by rain water? I have installed 2 solar panels in our home but i hanged a blocking diode outside. I used 2 diodes (1 each) namely 1n5401 and 1n4001.
     
  2. donkey

    donkey

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    Feb 26, 2011
    getting electronics wet is never a good idea. it can cause a short. its best to insulate the exposed wires/ components with a case, heat shrink(for wires) or in an absolute rare occasion tape.
    if a single diode gets wet then the electricity can flow backwards using the water as a conductor. this will render the diode a useless piece of equipment in your setup.
    at worst if you have 2 diodes close together they can short both the batteries and the panels which again will lead to issues.
     
  3. marky1993

    marky1993

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    Aug 5, 2012
    THanks for the info sir but during the testing stage, i noticed that the max voltage at the bigger panel is 20 and when i connect that to the load, it gives me approx. 2 Amps. will that be enough to use the water as a conductor?
     
  4. donkey

    donkey

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    Feb 26, 2011
    I could answer this but it will take along time. simply put pure water will not conduct at all but even rain is not PURE water. the thing that makes water a good conductor is the impurities.
    as the impurities are different from drop to drop I could not tell you how much current will be conducted, but rule no1 of electricity is NEVER EVER EVER mix water and electircity. EVER
     
  5. duke37

    duke37

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    Jan 9, 2011
    Water will conduct at any voltage if it is not pure. Pigeon poo does not help!
    If conduction occurs it may upset the operation of the gubbins but will also give electrolytic corrosion which can give all sorts of problems. Transistors do not work very well with only two legs, so keep it dry.
     
  6. donkey

    donkey

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    oh and just an addition to my last post
    EVER EVER!!!!!!!!!!!!!!

    and what duke said is also a great contribution I clean forgot about corrosion
     
  7. marky1993

    marky1993

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    Aug 5, 2012
    I put a waterproof junction box for the circuit to prevent the water. thanks once again... =)
     
  8. john monks

    john monks

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    Mar 9, 2012
    I remember when I tested electric motors submerged in water. I wanted to make a small submarine. During my last test the motor lasted 10 days under water continuously before failure. In that case the brushes wore out.

    Should high tension lines be insulated?
     
  9. KJ6EAD

    KJ6EAD

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    Aug 13, 2011
    Yes and they are, by air and glass/ceramic insulators.

    At an old job, I had an AT power supply submerged in dirty water while powered until it failed. The electrolytic corrosion effects were fascinating. I remember seeing large diode leads concentrically eroded to the point of separation. I didn't look for the deposition site but it was probably the entire ground rail or some of the power rails.
     
    Last edited: Aug 5, 2012
  10. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Depends in whether they're immersed in a large amount insulating fluid or not.
     
  11. Harald Kapp

    Harald Kapp Moderator Moderator

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    That's why oil is used to cool e.g. large transformers (and I don't mean the alien species) :)
     
  12. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    I was thinking of the insulating fluid used as an insulator for the majority of power distribution cables. (air)
     
  13. Alchymist

    Alchymist

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    Apr 16, 2011
    I do occasional derusting of steel such as machine parts. A bucket of water right from our tap, a scrap steel anode, a rusty part, battery charger and some wire is all that's needed. With the metal parts several inches apart in the water and 12 volts applied, currents in the 2-3 amp range can be expected.
     
  14. marky1993

    marky1993

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    Aug 5, 2012
    how long do you think will the diodes be fully corroded after it first got wet by rain water? I used the blocking diode that I used when i didn't put yet the junction box...
     
  15. duke37

    duke37

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    Jan 9, 2011
    I do not think it possible to answer your question. The rate of corrosion will depend on many factors. The wires may last minutes or months. I suggest that you change any components which have corroded leads. I have seen the leads breaking off transistors close to the can.

    I use Waxoil which is intended to rust proof cars to keep moisture at bay in equipment which may get damp.
     
  16. john monks

    john monks

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    Mar 9, 2012
    If you have a 12 volt system I would not worry about it.
    Rain water conducts at such a low rate it almost can't be measured.
     
    Last edited: Aug 12, 2012
  17. Raven Luni

    Raven Luni

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    Oct 15, 2011
    Dam - what are we going to dissolve electrolytes in now? :p
     
  18. john monks

    john monks

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    Mar 9, 2012
    Funny you mention that.
    Electrolytic capacitors is one example where water and electricity are mixed together.
    On a more serious note I understand and appreciate the concern about mixing water and electricity. Normally I would be very concerned about it to but in this situation I believe things are getting a bit out of hand. We are talking about very low voltage and rain water and a diode. I assume this is up high and not siting in a mud puddle. I remember testing rain water for conductivity and I was stunned with how poor a conductor it is. And besides I remember running about 300 meters of audio line from a church to a transmitter site much of it bare in the rain and snow for years and never had a problem.

    I'm not to interested in desolving any electrolytes.
     
    Last edited: Aug 12, 2012
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