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Transformer for a stun gun circuit.

Discussion in 'High Voltage' started by zoom, Feb 1, 2012.

  1. be80be

    be80be Well-Known Member

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    Don't use a transformer from a camera flash it could kill you. There a lot of good stuff on the net about these Looks like the best transformer would be a bobbin type I seen one made where

    you wrap the primary then a paper then a coil that would step up say 500 volts paper and add next 500 more and keep going till you added 10 or so coils and then seal it in epoxy.

    The voltage rating have to be off 100kv would jump 10 inches you sure couldn't hold it in your hand.
     
    Last edited: Feb 5, 2012
  2. colin55

    colin55 Well-Known Member

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    use a transformer from a camera flash. It is powered by a 1.5c cell. Use 6v. This will produce about 2,500v output. Put a number of 450v electros in series from the camera modules and connect them to an air gap.

    In series with the air gap you put the final high-voltage transformer primary of about 40 turns on a 10mm ferrite rod 50mm long. Wind layers of turns over the primary and interleave with high-insulation material.
    Each layer will produce about 10kV. It's a flyback transformer and everything you have read from the replies above does not apply to this design. No-one above knows what they are talking about.


    .
     
    Last edited: Feb 5, 2012
  3. be80be

    be80be Well-Known Member

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    Don't use a transformer from a camera flash it could kill you. This is the kind of shock it can make if you don't watch out View attachment 60847

    I no this collins the flash transformer can

    As shown in the chart, shock is relatively more severe as the current rises. For currents above 10 milliamps, muscular contractions are so strong that the victim cannot let go of the wire that is shocking him. At values as low as 20 milliamps, breathing becomes labored, finally ceasing completely even at values below 75 milliamps.
    As the current approaches 100 milliamps, ventricular fibrillation of the heart occurs - an uncoordinated twitching of the walls of the heart's ventricles which results in death.

    Above 200 milliamps, the muscular contractions are so severe that the heart is forcibly clamped during the shock. This clamping protects the heart from going into ventricular fibrillation, and the victim's chances for survival are good. View attachment 60848
     
    Last edited: Feb 5, 2012
  4. dave

    Dave New Member

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  5. colin55

    colin55 Well-Known Member

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    Who says the picture is from a camara electro???????
    Can you stop giving completely false and misleading information.
     
  6. be80be

    be80be Well-Known Member

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    It's not misleading information it's just fact's , And seeing I handle high voltages at work I no what can and will happen if your not careful.

    The bulb in a flash doesn't flash with low current like 20mA it's in the 100 to 200 mA range just get a bulb and see what it takes to make it flash or better just look it's rating up

    And I really don't see where you come off with your statements I tell the OP to watch out with a flash transformer it was for his safety.
     
  7. audioguru

    audioguru Well-Known Member Most Helpful Member

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    It is the high voltage capacitor in a camera's flash circuit that can deliver a few hundred milliamps for a moment. The circuit produces a fairly low current that slowly charges the capacitor.

    Most criminals in my part of the world wear clothing so tens of thousands or hundreds of thousands of volts are needed to arc through it. A few hundred volts from a camera's flash circuit will not arc through clothing but will zap a naked and wet criminal.

    Stun-guns have killed many people, some of them were innocent (the police zapped and killed the wrong guy).

    Why are we talking about an illegal and deadly stun-gun?
    MODERATOR, please close this thread.
     
  8. 4pyros

    4pyros Well-Known Member Most Helpful Member

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    Who said we were?
     
  9. be80be

    be80be Well-Known Member

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    Uncle $crooge What I'm saying is be careful with this these are not a toy and made wrong the out come could be bad.
     
  10. 4pyros

    4pyros Well-Known Member Most Helpful Member

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  11. be80be

    be80be Well-Known Member

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    4pyros that a great site lots of good info.
     
  12. rfranzk

    rfranzk Member

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    Transformer for stun gun

    Hello all,

    Several years back I started experimenting with electronics and was intrigued with HV. My first project was a stun gun based on a 555 timer,audio transformer and some mylar caps. It used an air gap to switch the primary. With that setup on a 9V battery I was able to get about 1600V. I used one of these transformers CD25 http://www.amazing1.com/transformers.htm at the output and got about 40KV, then used an automotive ignition coil and got 100KV. this was by no means in a small package with thru hole components. I also experimented with a 600V Sidac to switch the primary but this did not allow complete saturation so a lower output was achieved.

    Again a warning. High Voltage can be DEADLY. Be careful.

    Check out this site for laws and stun guns for sale for personal protection.
    http://www.beststungun.com/stun-gun-laws.html

    Thanks, Rfranzk.
     
    Last edited: Feb 8, 2012
  13. debe

    debe Active Member

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    Most HV stun circuits use a capacitor discharge type system. A LV to HV DC inverter is used to charge a capacitor to around 300V dc, this is then discharged across the HV transformer. The 300V capacitor is dumped across the TF windings using an SCR which is pulsed by a timing circuit. Very simmilar th an electric fence unit, only more grunt.
     
  14. TechnoGyppo

    TechnoGyppo New Member

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    As long as you don't actually 'weaponise' (ie make it so that is is easy to carry and operate at the same time or disguised) the device it should be legal to experiment with. A good transformer can be found in an electronic ignition from and old gas cooker - usually they have multiple outputs and you can series connect the output coils to get 100kV accross all of the coils.
     
  15. Blueteeth

    Blueteeth Well-Known Member

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    Although I generally never say 'never' - you won't get 500kV out of a transformer without some serious insulation. The output voltage claimed by stungun manufacturers are misleading for the purposes of advertising to those who don't know/care about how they work (consumers don't need to know at all). The maximum output voltage is determined by the sparkgap length and conditions of the air/medium in that gap. Since the output of a transformer driven by a capacitor discharge is essentially a current source, it's voltage will to whatever voltage is necessary to make current flow - often the breakdown voltage in the insulations of windings.

    If you have a 1mm air gap, a stungun rated at '250kV' won't output 250kV, but most likely in the order of 2kV.

    Also, stunguns are rather crude devices with manufacturers making claims about 'tetanisation' or how long it will keep an attacker of a certain weight on the floor. Whilst there are certainly devices specifically for creating tetanisation, it is impossible for the manufacturers to know the circumstances in which devices will be used, and so, their claims cannot be proved/disproved. What may 'sting' a bit for someone, can quite easily kill another, and visa versa.

    I've been unfortunate to conduct mains on a couple of occassions, as well as brush my hand across the terminals of a 800uF cap charged to 420V and whilst the fact I'm still here means I could say 'naa its not that dangerous', others have been killed from far less - not to mention the secondary effects.

    The way I see it with so many 'wanna build a stungun' posts on the web is, if you truely want to build one, then you have the tenacity to take the time and effort to reseach the electrical, and electronic engineering to work things out for yourself. I think the OP can understand why so many are guarded, given the (il)legality and dangers.
     
    Last edited: Feb 11, 2012
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  16. audioguru

    audioguru Well-Known Member Most Helpful Member

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    I am glad that your heart is not in your hand. Your heart is in your chest. If you brush 420V on your chest or between your hands then your heart will probably stop beating.
     
  17. Blueteeth

    Blueteeth Well-Known Member

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    Probably, but it was from a cap :) My other hand was grounded via a static-wrist band. The burn was more of a concern at the time, but it was enough to kill... The '15mA' figure varies person to person, and thats 15mA across the heart - not the chest. Otherwise defribulators for external use wouldn't have to use 2000V @ 300J, and electric chairs could run off NiCads. Continuous power is far more dangerous, AC, or DC, but at the right time, in the right conditions, a pulse of >120V, even from a smaller cap IMO, would be enough to meet the angels :/

    I wasn't showing off recounting how many times I've been dumb enough to get electrocuted, just that, any numbers referenced talking about 'whats dangerous and what isn't' are misleading, both in over-stating dangers, and understating. Too many variables to come up with a definate 'safe level'
     
  18. be80be

    be80be Well-Known Member

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    At work before they closed the place down. We had a computer room that had the phone lines in it. Most of the blocks are punch down but some of the older lines have blocks that have nuts to hold the wires. It was a real hot day and I bumped into the blocks You talk about a shock the block hit my back I could feel my body draw up it was so strong of a shock. The T1 lines can have over 190 volts on them

    I really think if I had fell on this I would of been a goner. I fell away from the block. I been shocked before but never like this. I learned some new respect for any line with voltage on it
     
  19. ljcox

    ljcox Well-Known Member

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    This is wrong.
    Z2/Z1 = N^2, so N = SQRT (200) = 14.14
     
  20. Blueteeth

    Blueteeth Well-Known Member

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    Turns ratio only *really* applies directly when you're feeing a transformer with constant AC. Under pulse conditions with the secodary as open circuit - its really behaving as a coupled inductor, as the secondary is open, it might as well not even be there. The magnetic field builds in the coil during the pulse, then colapses creating back EMF (flyback) in the primary and secondary. If the turns ratio is say 1:10, and your pulse reaches 300V peak, the back EMF could easily reach 3000V. Multiply that by the turns ratio and you have 30kV. So, what looks like something that would require a 1:100 turns ratio transformer, could actually be done with a 1:10. It's how flyback transformers work.

    Of course the turns ratio is important, but the voltage 'gain' is part of the primary, just multiplied by the secondary.

    Audio transformers are less than ideal for any high voltage apps. Low voltage insulation, and high inductance (they are dealing with audio frequencies after all...) make them useless for anything >1kV. I'm sure one could get a good spike of voltage out of them grater than 1Kv, but in terms of efficiency, and reliability - its wasteful, and would be disappointing.
     
  21. ljcox

    ljcox Well-Known Member

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    I suggest that you use an EHT transformer from an old CRT television set.

    However, colour TVs have an EHT of about 25 kV, so be sure to discharge the tube before handling.

    Microwave ovens have a transformer that provides about 3 kV.

    But be careful.

    There is a capacitor in them that can store the 3 kV for a long time, so it needs to be discharged before you start removing parts.
     
    Last edited: Feb 12, 2012

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