Disposable Camera SGTC Tutorial
Chapter 1. About the tutorial
I wrote this tutorial mostly for fun. I thought someone could have use for it. This is geared towards
the beginner, as this is more a hands-on tutorial than a theory explanation. Sorry, no real pics, I don't
have the coil assembled any more. Hopefully someone has use for this!
Chapter 2. What do we need
Basically, we need the following:
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One or more disposable camera flash boards
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Pulse rated capacitor, 1-5nF@2kV at least (it's better to get many of them for easier tuning)
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10 or more capacitors, 1nF@600V should be enough, I used the small ones from the flash
boards
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10 or more diodes, preferably UF4007, or the black ones on the flash boards
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A limiting resistor, 1-5Mohm, should be 1W or more so it won't arc over.
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50m or more magnet wire, preferably 20-32AWG (0.2-0.3mm)
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Thick wire for the primary, 1mm or more diameter recommended
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Primary and secondary formers
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Bolts or nails for the spark gap
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Battery holder (2xAA or 2xAAA)
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A small switch
I think there are all the parts that are needed. Now let's get hands on the project!
Chapter 3. Let's build it!
Preparing the 3-to-660Volts converter
Get one of your flash boards. There should be a part like this:
This part is called a diode. Notice the end where the grey stripe is? Put a mark to the board to that
end. Now desolder the diode. Then solder a wire on your marked hole. This is your HV out. Solder
another wire on the negative side of the battery holder. This will be your ground.
Also solder your 2xAA(A) battery holder to the board's original holders.
Making the Cockroft-Walton multiplier
Here's how I did it:
So the HV out from the camera board goes to the ”660V in” and the ground wire to ”GND”. Solder
another ground wire to the GND.
Now you should test it. Put batteries into your holder. Now hold the GND wire of the multiplier and
bring it close to the resistor's floating end. You should be able to pull a dim, ~5mm arc.
The Tesla Coil
The schematic of this TC is as follows:
You can wire this any way you like, just remember to watch for dead shorts!! Notice: if your cap is
rated for only 2kV, don't make the spark gap wider than 2mm!! Otherwise you will kill your cap.
Air dielectric strength is approx. 1kV/mm, so with 2mm gap the cap will charge to ~2kV before
firing.
The spark gap can be a pair of nails, bolts, anything which is conducting, with a gap between them.
Now begins the difficult part:
Primary and secondary
It's good to start with winding the secondary. Find a former which has a diameter of not much more
than 5cm. Then wind the magnet wire on it with no overlaps.
Then go to the JavaTC website. Enter your secondary coil parameters and your cap size. Then start
thinking of the primary. I used a solenoid primary, which is no good with spark gap coils. The
primary inner diameter should be at least 1cm wider than the secondary diameter. Just throw in any
turns count, JavaTC will do the rest.
Now scroll down and tick the box ”Allow JAVATC to tune my coil”. Then click ”Run JAVATC”.
Now the program should start tuning the coil. Once it's finished, check the primary coil fields for
reference for the primary turns count. If the primary gets too big, change the cap size.
Then wire everything together, and put power on! The spark gap should start firing. Sparks from the
coil can't propably be seen in daylight. Bring it to a dark room to see 'em!
Good luck!