Experimental Fun

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A friend was throwing out an old rear projection tv which I managed to salvage a few parts out of, such as high voltage wire, a quite decent sized flyback transformer and some Ethylene Glycol from between the lenses and the CRT screens, which can be used in computer liquid cooling systems.


I decided on making a high powered stun gun as i thought it would be another interesting project and a quick one as my time has been limited lately. I was aiming for having a voltage of around 40KV (40,000 volts)  but ended up with 10-15KV due to internal limitations in the flyback transformer and limited input voltage from the flyback driver module. The driver module was purchased on ebay for a steal at $20. I decided to use my trusty lithium battery packs in series to generate 18-19 volts of input power @ 30 amps. Which worked out nicely as they fitted into the handle snugly.



Originally I was going to use 630VDC capacitors in series to produce a length that could handle up to 40KV, but on experimenting and further research resistors would need to be added between each capacitor to create an even voltage across all the capacitors or it could cause a catastrophic failure of the capacitors. So at the moment I'm waiting for some 20KV capacitors on order and they will be wired in parallel to give approx a 15 joule output. As seen in the video at the bottom of the page, microwave capacitors have been set up in series to handle 12KV and demonstrate the power levels created by this device.


Always use common sense around electricity and be safe. 

 

PVC fittings purchased from Bunnings to build the outer shell, the outer shell thickness was doubled by using a combination of couplings and PVC pipe to contain the hazardous high voltages.

The flyback has numerous pins o the bottom for various voltage outputs and inputs for different functions which won't be needed. So the secondary winding had t be identified using a voltage on the primary wiinding which in turn would produce a voltage across the - and + on the secondary winding.(Note: You cannot identify the secondary winding by using a multi meter on the OHMS setting). As seen in the picture two additional Primary windings were added to the ferrite core, as the internal windings did not meet my requirements.


The unused terminals were snipped off and then an epoxy was poured over them and the protruding secondary winding wire to seal it all in place and prevent the possibility of arcs.

The flyback and flyback driver ready to be placed inside the casing.

Nice fit!

Almost done, just needed to add the trigger and safety switch.