400v Transformer for Geiger circuit

Discussion in 'The Projects Forum' started by turtleaja, Nov 13, 2012.

  1. turtleaja

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    Nov 13, 2012
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    Last edited: Nov 13, 2012
  2. KMoffett

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    Neither link works. ???

    Ken
     
  3. MrChips

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    A Geiger counter requires very little current. You can build a HV supply using a small transformer and a voltage multiplier circuit consisting of a ladder network of diodes and capacitors. Google voltage multiplier.

    Edit: Broken Links - do not cut and paste links into the message box. Use the link icon in the tool bar.

    http://www.goldmine-elec-products.com/prodinfo.asp?number=G13599
     
    Last edited: Nov 13, 2012
  4. turtleaja

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    Nov 13, 2012
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    Does it work now?
     
  5. turtleaja

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    Nov 13, 2012
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    My problem is I can't find a suitable transformer. Where should I go to find a suitable one?
     
  6. Dodgydave

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    Jun 22, 2012
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  7. KMoffett

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    I did this one without a transformer. Cut down the number of multiplier stages to lower the output voltage.

    Ken
     
  8. turtleaja

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    Nov 13, 2012
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    That looks really interesting. Where did you get it from?
     
  9. KMoffett

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    My head. Here's another.

    Ken
     
  10. Externet

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    Nov 29, 2005
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    For about $1, the whole circuit inside a disposable camera that you removed the exposed film.
    Just remove the trigger switch, and keep fingers away as its > 350V DC will give you the giggles.

    Ahh... battery included.
     
    Last edited: Nov 13, 2012
  11. turtleaja

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    Nov 13, 2012
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    That sounds really cool. What if it doesn't output the full 400v? Can I just take two and connect them together?
     
  12. Externet

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    Perhaps feeding about 2 to 3 V instead of the 1.5V cell will raise the voltage. I believe their storage capacitors, usually unlabeled, are rated 450V DC.
    Or, try different brands of such cameras. Older ones are sturdier, have larger flash bulbs and perhaps higher voltage output.

    Using more than one is not advised. Checking for one that has a 'better' low-leak storage capacitor, removal of the bleed resistor or the neon "ready" indicator lamp will raise the voltage somewhat. Measure and try.
    After disemboweling the camera you may end even with the housing where to fit the connections end of the geiger tube if small enough.

    Here is 1 inch tubes ----> http://ea4eoz.blogspot.com/2012/09/drsb-88-review.html

    Guess what... found that someone already thought of that ! ----> http://madscientisthut.com/wordpres...pply-hack-using-disposable-camera-flash-unit/
     
    Last edited: Nov 13, 2012
  13. turtleaja

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    Nov 13, 2012
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    My tube is actually 8 inches :)

    I will go get a disposable camera and try to see how well I take everything apart and what voltage it outputs. I honestly didn't even know they still sold disposable cameras.

    I'll come back as soon as I can get one and rip it open. >300v seems dangerous, any special safety precautions you could recommend?
     
    Last edited: Nov 13, 2012
  14. Externet

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    - Take pictures,
    - crack open as best as you can,
    - remove 1.5V cell
    - short circuit the large storage capacitor with an insulated handle, a spark may fly.
    - remove film roll
    - go for your project.

    These processed cameras are usually free if asked politely to a developing place, they may even show you how to open them.

    Check the whole enchilada, found that someone did it already, removing the usually leaky storage capacitor:

    ----> http://madscientisthut.com/wordpres...ble-camera-flash-unit-to-power-a-geiger-tube/

    Nice ! ----> http://www.kodak.com/ek/US/en/Global_Sustainability/Health_Safety_and_Environment/HSE_Support_Center/Product_End_of_Life_Management/Opening_Instructions.htm
     
    Last edited: Nov 13, 2012
  15. MrChips

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    Yes, discharge that big 300μF 300V (or whatever) capacitor through a resistor before handling.
     
  16. paulktreg

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    ... and change your avatar it's really distracting! ;)
     
  17. turtleaja

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    Nov 13, 2012
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    There certainly was a big spark from that capacitor, unfortunately I found out where it was with my hand before the screwdriver found it.

    How can I test the transformer to see what it outputs? Do I have to desolder it first?

    The camera and flash work, and when I connect the battery the transformer gets very hot so I believe that means it's working.
     
  18. Externet

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    Do not desolder nor dismantle anything !

    "Very hot" does not sound good...

    That voltage on the capacitor that gave you the giggles is what you have to measure with a voltmeter, NOT WITH YOUR FINGERS. THAT is what you want to know, the whole circuit is there, no need to take parts out. It generates about 400V by itself. Just connect it to your Geiger tube..

    So, install the 1.5V cell, turn its swich on and measure the voltage at the big capacitor.
     
  19. turtleaja

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    Nov 13, 2012
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    Hmm, something must of went wrong because there is no increase of voltage to where the capacitor used to be (I removed it because I didn't want another shock).

    The transformer still heats up, just not anywhere close to as hot as it heated up before. I am so confused. Could me shorting the capacitor with my screwdriver have messed something up?

    I may just get a new one and make sure not to touch anything. I thought the goal here was to remove the transformer, but your right in that I should just leave the whole circuit intact. I know exactly how the whole thing is situated now and I can actually avoid draining the capacitor altogether.
     
    Last edited: Nov 15, 2012
  20. Externet

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    If you are unable to discern or understand the workings of the camera circuits, it is better you stop playing with it and risking more shocks by mishandling.

    Study the schematic for such, understand its workings first.
    ----> I do not feel like guiding you beyond this point if you lack skills to handle high voltage.

    Understand at least this : Your wanted 400 V are not to be obtained by removing the camera transformer or capacitor or other components. The camera WHOLE circuit does produce them.
     
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