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transformer for 555 taser gun

Discussion in 'Electronic Projects Design/Ideas/Reviews' started by redpepper007, Apr 19, 2012.

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  1. redpepper007

    redpepper007 New Member

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    So, basically i'm going to create a 555 based taser with somewhere about 20-30kV output (input is 9V or 3*18650 in series). Found this schematic on google and it seems kinda simple:

    [​IMG]

    so I went to nearby electronics store and got all components except for the transformer. They had no idea what does 1k:8R means and asked me for input/output voltages - does anyone knows what kind of transformer would be okay? And if that matters, I'm gonna add a few more voltage multiplier stages (total of 5 or 6)
     
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  2. colin55

    colin55 Well-Known Member

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    1k:8R is the standard way to represent an audio output transformer.
    Alternatively you can use the oscillator from the flash of a disposable camera.
     
  3. redpepper007

    redpepper007 New Member

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    well then what do I tell to the person in the store? They said its not enough with the 1k:8R; that they need to know input/output voltages... I dunno, is it really 9v/1000v?

    this is where I got the schematic: http://www.555-timer-circuits.com/stun-gun.html
     
    Last edited: Apr 19, 2012
  4. dave

    Dave New Member

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  5. Reloadron

    Reloadron Well-Known Member Most Helpful Member

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    What part of that do they not understand? It's an audio transformer with a 1KΩ primary and an 8Ω secondary. It is used in reverse with the 555 driving the transistor which then drives 8Ω secondary side. You want something like this a very common audio transformer. How stupid can electronic component sales people get? There is no input output voltages with an audio transformer of this type.

    Ron
     
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  6. colin55

    colin55 Well-Known Member

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    1k:8R on a transformer has nothing to do with voltages.
    It is an impedance ratio.
    The circuit I produced above is designed for those who have a knowledge about electronics.
    You are just being led astray by shop assistants who know nothing about electronics.
    You need to learn about transformers before making the circuit.
    Unfortunately that's a difficult issue because transformers are going out of fashion.
     
  7. redpepper007

    redpepper007 New Member

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    Thank you for your replies, I'll visit them tomorrow and get the proper transformer. And I am studying electronics so this is gonna result in some useful knowledge.

    Oh, one more thing - what kind of isolation do I need for the soldering? I'm gonna plant this on a standart PCB board and those holes for soldering are really close to each other, and as we are dealing with very high voltages, there migh be electric sparks, right?
     
    Last edited: Apr 19, 2012
  8. canadaelk

    canadaelk Active Member

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    A transformer with an 8R:1kR ratio is the Hammond 146K. But there is no way you will get 20kV out of this circuit
    But even the voltage you will get out of it can be dangerous and, hopefully, you will be the first one zapped! E

    Einstein: There is a limit to mankind's intelligence but not to his stubidity
     
  9. redpepper007

    redpepper007 New Member

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    Yeah, I already figured out that there is no way I'll get 20kV out of this thing; and I am pretty sure that the first person shocked with this will be me, ill let my sis to try it on me. Uhhm, this circuit can't generate enough current to kill me, right? It just draws somewhere about 10mA from the battery, as I've read on other sites and thats not deadly, is it?
     
  10. Reloadron

    Reloadron Well-Known Member Most Helpful Member

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    Don't underestimate that circuit. Doing the math the output of the audio transformer can be as high as 1 KV. Now I see what looks to be an 8 stage multiplier. The 1N4007 diodes are 1 amp 1 KV diodes. When built correctly that little circuit will work just fine. The trick (if there is a trick) is knowing how the circuit works and as Colin mentions understanding what is going on with the transformer and how that part works.

    As to lethal current? I suggest Google is your best friend. There are a hundred variables in defining lethal current.

    Ron
     
    Last edited: Apr 19, 2012
  11. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Low power audio output transformers were used 60 years ago. Maybe nobody sells one today.
    If you find one then you are lucky if it does not breakdown with 300V. And you want kV?"
     
  12. canadaelk

    canadaelk Active Member

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    OK: Please correct me if I got this wrong: The trany is 8R:1000R. That is Root of 1000:8 = 11.2 turns ratio. If you have 10 V on the 8R you get 112V (less losses) on the 1kR. Than at the output 1.6kV. E
     
  13. audioguru

    audioguru Well-Known Member Most Helpful Member

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    With a 9V supply, the output of the 555 is only about 6V p-p. Then the output voltage of the 8:1000 transformer is only 67.2V.
    The voltage doubler has only 4 stages so its output will be only +268.8V, not tens of thousands of volts.
     
  14. canadaelk

    canadaelk Active Member

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    AG: Using your number on the secondary of the trany should the output voltage not be 538V? E
     
  15. audioguru

    audioguru Well-Known Member Most Helpful Member

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    The output of the 555 is 6V p-p when it is powered by a brand new 9V battery.
    The stepup ratio of the transformer is 11.2 times.
    There are 4 voltage-doubler stages.
    Then 6V x 11.2 x 4= 268.8V. Enough to give a shock.
     
  16. colin55

    colin55 Well-Known Member

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    The transformer works in FLYBACK MODE.

    [MOD EDIT: Please refrain from using offensive language.]
     
    Last edited by a moderator: Jun 10, 2012
  17. audioguru

    audioguru Well-Known Member Most Helpful Member

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    If the darlington breaks down at its rated 80V and the transformer steps it up to 896V, then the 4 voltage doublers will produce 3584V.
     
  18. colin55

    colin55 Well-Known Member

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    How are you going to get 80v on the primary side of the transformer?
    What are you talking about??????????????????????????????????????
     
  19. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

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    555-timer-circuits.com claim copyright on this Stun Gum circuit,
     
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  20. colin55

    colin55 Well-Known Member

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    Deleted Off Topic.

    Moderation.
     
    Last edited by a moderator: Jun 11, 2012
  21. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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