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Capacitor neutralization circuit not discharging

Discussion in 'General Electronics Discussion' started by ratstar, Aug 20, 2018.

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  1. ratstar

    ratstar

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    Aug 20, 2018
    [​IMG]

    the double diodes are led's.

    the cap in this circuit has effectively its legs touching, but its not discharging!
    this cant possibly be the case, but it has been this way for a long time with a lot of tests!

    Can I get some advice on this?
     
  2. ratstar

    ratstar

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    Aug 20, 2018
    Heres a vid for demonstration.



    Ive tested it alot of times, with this result.
    It actually just doesnt make sense, im starting to get superstitous.
     
    Last edited: Aug 20, 2018
  3. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Maybe whatever resistor you have there is to high a value to be able to see any visible light from the led.
     
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  4. ratstar

    ratstar

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    Aug 20, 2018
    If you notice in the video, I actually connect the wire and the reverse polarity led lights up, its when its solidly connected it doesnt seem to want to go down it. (even when i disconnect from battery straight away!)
    Its only a 14cm of nichrome wire ( looked it up ->1.50 × 10^−6 Ωm ) , its not much resistance at all.

    And the led is still pulsing, even during the loop being connected - which means the cap is filling all the way, its just not discharging at all.

    hmm... I might be missing something...
     
    Last edited: Aug 20, 2018
  5. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Maybe the capacitor has already self discharged?

    Or maybe you have poor connections.

    I would connect a multimeter across the capacitor so I had a good indication of the voltage across it.

    In addition, you are not limiting the current through the LEDs. If you've been discharging into a short circuit the led in the discharge path may well have been damaged. One thing I've seen with damaged LEDs is that they may not turn on at low currents, or exhibit delayed turn on. Either or these could cause you not to see the discharge LED illuminate.
     
  6. ratstar

    ratstar

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    Aug 20, 2018
    Thanks for the help.
    Indeed I admit I am very lazy with my equipment - yes ive gone through a fair few leds... and the connections are an issue with just twisting wire together.
    I dont have a multimetre, im just debugging off my leds.

    If the capacitor was discharged then id be able to put more current through it - and I cant, unless its all seeping through invisibly.


    and. some more madness - ive drawn up a circuit (tested) which is even more wrong...

    [​IMG]

    This circuit is supposed to discharge MORE than it charges! (I think this because there is the fork and about 50/50 sans the capacitor should be going down both) and if you count the resistance of the led's the discharge path has more freedom (the charge path has a fanout before it.) - so the cap should be empty, but it just seems like its plugged up.

    (about deillumination)
    I had an idea tho, it could be that discharging and charging at the same time is giving me 0 amps through the cap, but I dont think its supposed to be that way? the cap should just end up becoming a constant leak no?
     
    Last edited: Aug 20, 2018
  7. WHONOES

    WHONOES

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    The LED's will reach a point where they stop conducting. The capacitor will not discharge below this value although self discharge of the Cap' will eventually get you there.
    I'm not saying that this is the issue here but, depending on the type of capacitor, there is the phenomenon of dielectric absorption to deal with. This manifests itself when you discharge a capacitor with a dead short then remove the short and find that there is still a voltage present on the Cap'. It can take many attempts to remove the residual voltage. See the link below for an explanation.
    https://en.wikipedia.org/wiki/Dielectric_absorption
     
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  8. ratstar

    ratstar

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    Aug 20, 2018
    Thanks for kind info Whonoes.

    They can just be resistors instead of the Leds, ive tried both and im getting the same results, im just using leds because they seem about what I need and my resistors are all too high in ohmage (and to tell the truth im hopeless at reading the value. :) ) When I use nichrome wire (which is a very light resistor for its length.) I just drop out completely, as if it all going down the other line skipping the capacitor.

    Something is funny is going on... im desperate. 4 months no (solid state) oscillator. Im dizzy and im frustrated, and its not making any sense.

    About the dielectric absorption - Ill read up on it for sure, adds physical complexity to your bug finding. My "conduction model" I have in my head is too simplistic to explain everything that happens.
     
    Last edited: Aug 20, 2018
  9. WHONOES

    WHONOES

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    What is the other line that you mention? Also the solid state oscillator. Could you expand on what you are doing, diagrams or explanation or both.
     
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  10. ratstar

    ratstar

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    Aug 20, 2018
    [​IMG]

    About the solid state oscillator-> this is the "main part" of it, and unless I can sort this out it has to stay a broken idea. I use a couple of 1 wire inverters, and when one cap charges it causes the other cap to spill, but it doesnt work unless I can get this cap to discharge itself, when the charge current drops to 50% (its 50% drop during a charge from a side, because both sides are symmetrical.), from side b to side a, between a positive pole and a negative pole.

    Its a bit like a multivibrator, its a 2 section system. when one side is charging, the other side gets weaker (it has power stolen from it, from the other cap charging.) and put into discharge. then over and over.
     
  11. ratstar

    ratstar

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    Aug 20, 2018
    better clearer video of the situation

     
  12. ratstar

    ratstar

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    Aug 20, 2018
    GEEZE!!! All I added was a tad more resistance on the loop and it started working!!!

    sorry, this is confusing!!!
     
    Last edited: Aug 21, 2018
  13. WHONOES

    WHONOES

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    May 20, 2017
    Still don't understand what you are trying to do.
     
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