# COMMUNITY : FORUMS : TECH

## can anyone help an extreme amatuer wire a group of capacitors together?

I'm in the process of making a version of the tazor glove instructable, but I'm trying to make it more compact while still powerful. I've 'liberated' a few capacitors from some old pc cards but I'm not sure what I need to look for to know voltage or amps or whatever it's measured in, and some don't seem to any helpful markings at all. What I'd like to do if at all possible is wire as many capacitors as I'm able into a line that can circle the wrist, but I'm not sure how to do it or whether it would matter if the capacitors are of different sizes/powers. If someone can help I'd be very appreciative but keep in mind I'm a true amateur so any complex lingo will probably just confuse me, if you need to know anything else I'll let you know as soon as possible.

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pyper8 years ago
Capacitors are normal rated for voltage and capacitance, with electrolytic capacitors also having polarity. Electrolytics will store much more (orders of magnitude) energy for a given size than none polarised types but can only be used with DC

When your wiring capacitors into an array they follow the opposite rules of resistors. That is that capacitors in parallel will have a capacitance equal to the sum of there capacitance, and capacitors in series will follow the rule 1/Ct = 1/Ca + 1/Cb + 1/Cc ........ 1/Cn

In practical terms wiring them in parallel is easiest, but you'll need to take the voltage of the lowest rated cap to be safe. Wiring 2 identical caps in series will half there capacitance, but also half the voltage across each cap, so effectively this doubles the voltage rating of the caps when used together.

I think what you would want to do with the tazer glove is find some 400v electrolitics (Monitors and computers PSU's are a good sauce) and stick them all in parrelel. As for marking, electrolitics are the ones that look like little coke cans and should have everything clearly printed on the side, don't worry about mixing and matching as long as you pay attention to the voltages and the polarity.

Be warned however that a few joules of juice at 300v will kill you, I've used a larger flash gun charger to charge a little cap bank the size of my fist to 400v and it will blow chunks out of a screwdriver if you short it out. The energy stored in a capacitor is E=1/2CV2, once you get over a few J's your going to start killing people.
8 years ago
cpacitence shouldn't be cut in half when wired in series, say i wire 1uf capacitor to another 1uf capacitor, i should have double the voltage, at 1uf
8 years ago
Theres 2 ways you can look at this, either that by wiring the 2 identical caps in series you have created the same cap with twice the plate spacing

See how if this were melded into 1 capacitor casing then the middle pair of plates is not really connected to anything and is just going to be subjected to the fields set up by the outer pair of plates, hence you have effectively just doubled the plate gap.

Secondly consider the equation E=1/2CV2, if you double the capacitance you double the energy storage, but if you double the voltage you quadruple the energy storage. So if we doubled the voltage without halfing our capacitance then all of a sudden our pair of 1J caps could store 4J's when wired in series.
8 years ago
sorry mate, the formatting ate my ascii diagram :P
grantdevine (author)  pyper8 years ago
uuuhh...? Sorry, this just went right over my head
grantdevine (author) 8 years ago
So how do I tell how many Joules a capacitor puts out? And how much of a punch does a 6.3v - 1000uF capacitor punch?
8 years ago
Stored energy is given by
E=0.5 x C x v2

or half of the capacitance times the voltage squared. for your 1000uF cap it would be

0.5*0.001*(6.3*6.3)=0.02J

if it were a 1000uf 400v cap (hypertheticaly) then
0.5*0.001*(400*400)=80J

see how voltage makes a huuuuge difference. A 1000uf / 400v cap would be about the size of your fist btw.
grantdevine (author) 8 years ago
I also have a few small capacitors that seem to be 16v - 47uF, which makes little sense to me because my other capacitor has more than 20 times the uF, 3 times the volts and is half the size?!
Yerboogieman8 years ago
i have a capacitor so big i dont need to wire a bunch together. like 1,000,000 uf or something
Sandisk1duo8 years ago
What pyper said is true, here's a summary, 1.MAke sure that the capacitors that you want to solder are above 330v 2. if they ARE about 330v, then wire them, (+) to (+), (-) to (-) 3. pc cards shouldn't have capaitors over 10v, take some disposable cameras, crt monitors, computer power supplies apart, take out the huge capacitors 4. don't die