How to: Make a stun gun with a disposable flash camera

[Hotwired]

i also hit up radio shack and got some 500v 0.0047uf capacitors to replace the ones in the circuit. but there really small. did i fork up and get ones that wont work. i know Zeus said 0.1 to 0.47 but i didn't notice the extra zeros in mine till i got home. are they too small or will they give me a faster cyclical rate?

Using capacitors which store less energy will increase the speed the circuit cycles at but too little and you either get too little energy in the HV spark generated to ignite a mix reliably or no spark at all.

Unfortunately that's a lot smaller than I'd suggest.

[saint .357]

its cool, i saved the recite ill take it back tomorrow

[saint .357]

okay so i went and exchanged those for two 0.1uf 250 volt caps. i figure ill just chain them together for 500 volts. can you refresh my memory if i want to increase voltage do i run them in parallel or series? also do you think that will work?

[Hotwired]

With two of those in series you have a capacitor bank which is 0.05uf at 500V.

In parallel those two would be 0.2uf at 250V.

In short, capacitors in series lowers the overall capacitance but increases voltage rating.

In parallel it increases capacitance but the voltage stays the same.


The energy is still being increased with each capacitor being added because the voltage is part of how the energy stored in the capacitor is calculated.

[saint .357]

so if i put them in series would the capacitance be to low at 0.05?

[Hotwired]

so if i put them in series would the capacitance be to low at 0.05?

You should put them in parallel.

Why?

Your SIDAC is rated for 240V, having a capacitor bank which can get to 500V is worthless if the SIDAC will discharge it whenever it reaches 240V.

Capacitance is not the issue really, you are looking at the energy of capacitance and voltage together.

So from my original post:

The circuit I've demonstrated discharges a 0.22uf capacitor at 350V.

Energy in the capacitor is ½ CV^2 = (0.00000022 x 350 x 350)/2 = 0.013475J or 13.475mJ

If we plug in the values for your capacitors in parallel (0.2uf @ 240V)

I'm saying 0.2uf at 240V because that's what the SIDAC will discharge the capacitor at

(0.0000002 x 240 x 240)/2 = 0.00576J or 5.76mJ

So a bit less than half the energy in the capacitor per pulse.

I'd expect it to work but you can always add more capacitors in parallel if you need to.

[saint .357]

well i was going to chain 2 sidac's together 2 give me a discharge voltage of 480. i mean i got five of them so?

[Hotwired]

Can do, my only concern with that is how well the circuit can do 480V.

[saint .357]

you mean the charging circuit cause it shouldn't be a problem. the cap that's in there is already 400. and in my first stun gun configuration i had three 350v caps wired in to so.

[saint .357]

well i got the sidac and it works. its gotta a really good cyclical rate with the cap that's already in there. but still not getting any where near your power. the spark wont jump more then the space between the terminals that are already there. any way i can make more powerful spark. i tried putting more caps in both parallel and series but it didn't work. even went up to 1,200 volt caps and sidac's still not great arching. what am i doing wrong?

[Crna Legija]

arc it though a step up transformer like a car ignition coil

[saint .357]

but those are pretty big i need a system that's smaller one i can wear on my waist.

[Hotwired]

Insulate the terminals and double up the two coils in the ignition box.

3cm is what I'm getting max.

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[saint .357]

alright i'll try it, i got some liquid electrical tape.

[Fexo180]

interesting read this topic.. how would one go about tricking up a cattle prodder for a half baked tazer?