Cheap/free capacitor bank and charger

Cheap/free capacitor bank and charger
HOW TO: Make a capacitor bank useful for many applications, ie a railgun, coilgun, RFID zapper, for $0~50 depeneding on what tools you have and how fancy you want the final product.

**Now with solid state trigger**
 
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Step 1Gather Materials

Gather Materials
I have modified the circuit to use a solid state trigger, an SCR. I used this one, number from digikey: S4020L-ND
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=S4020L-ND

400v, 20A so ~200A surge, less than $2

The pins are, from left to right: Anode; Cathode; Gate
The SCR is essentially a diode, so be sure to hook the negative of the caps to the cathode and the anode to one of the binding posts. The positive of the caps also goes to a binding post. When you put enough current (check the chip spec, only a few volts and ma IIRC) through the gate it is "closed", allowing current to flow through it in the right direction. It will stay "closed" until the current flow stops, IE the caps are completely drained. Then you can just solder up a switch to the positive lead from the battery holder to the gate, this way you will be able to discharge even when the switch is off. I will put a new schematic up soon.

I applied all this to a coil gun and will write it up soon. This is just and update for those who request a solid state switch.

*****************************************************************************************************
Keep in mind that this is my first instructable, hell it's my first time wielding a soldering iron. Comments appreciated :D

The cheap way: (note that if you choose to go this way you should skip to step 4)
$0.00 (4) Disposable cameras You can get these for free used
$0.00 (X) Scraps of wire I used the wires from an old stereo system
$7.99 (1) Spool of solder (with soldering iron!)
$4.99* (1) Spool of 12 AWG wire.
$3.68* (1) Electrical tape
~$12

Assuming you already have everything but the 12AWG stuff, which you probably do, that's only $5. Hell, you could probably get away with paperclips if you were really trying to get it done cheap.

Required materials:
$0.00 (4) Disposable cameras You can get these for free used
$0.00 (X) Scraps of wire I used the wires from an old stereo system
$1.39 (1) LED holders (package of 2)
$1.49 (1) Green LED (package of 2)
$1.49 (1) Red LED (package of 2)
$3.00* (1) Toggle Switch
$1.49 (1) 2AA Battery Holder
$3.69 (1) Project Box
$4.99 (1) Binding Posts
~$17

Things you probably have but might not:
$7.99 (1) Spool of solder (with soldering iron!)
$4.99* (1) Spool of 12 AWG wire.
$3.68* (1) Electrical tape
~$38.20
*I just guessed the prices of *'ed items

I got all those parts at radio shack, expensive but that's what I pay for convienence.

Tools:
Soldering Iron
Multimeter
Drill
Assorted drill bits
Scissors

Note that I took the picture after I finished the project...
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275 comments
1-40 of 275next »
Sep 30, 2011. 6:46 AMliddleLOL says:
I need help:

I am making a charging circuit for a coilgun, but i accidentally bought non polar caps. I was wondering if i could still use these with some sort of circuit adjustment, or if i need to purchase all new polarized caps? Can you help?
Jun 30, 2011. 7:09 PMStartedBullet says:
Any idea where I can get these cameras free? Walmart will not give them away.
Oct 27, 2006. 12:26 PMcorax says:
It seems this relatively simple design would work for an emp generator experiment?
Jul 21, 2007. 5:35 AMDerin says:
what is a emp generator?i know i am dumb
Mar 27, 2009. 7:46 PMTheDeviant13 says:
emp stands for "Electromagnetic-Pulse" EMP pulses can knock out electronics such as radios and will make crt TV's
Aug 27, 2010. 2:45 PMfreerunnin1 says:
doesn't an EMP destroy capacitors or something? therefore rendering electronic equipment useless or is it just temporary?
Apr 17, 2011. 9:47 AMS33PlusPlus says:
I realize this is rather old, but EMP affects anything sensitive to sudden current spikes (i.e. semiconductors). Theoretically you *could* trash a capacitor with an induced current, but in reality all the transistors would explode far before a capacitor would catastrophically fail.

And @TheDeviant13: What do you mean "will make CRT TVs"? It will screw up the picture pretty bad, but that goes for all magnetic fields.
Mar 18, 2009. 3:09 PMblablabla123 says:
This would absolutely work, in fact, i made one work using the individual charger output
Jul 25, 2007. 4:54 PMGreasefire says:
EMP is shorthand for "electromagnetic pulse". In Ocean's eleven, they used a generator the size of a van to knock out the casino's power grid (along with half the city's! ;])
Jul 18, 2008. 5:43 PMgoogleman says:
oceans is cool
Oct 25, 2007. 1:50 PMfiremanfu says:
you also get an emp from a nuke going off
Jun 13, 2011. 9:11 PMalphapyr0 says:
not just any nuke it would have to be a ytterbium core HE rail nuke.
Jun 22, 2011. 6:56 AMarizonadixon says:
this is not necessarily true, any nuclear weapon with sufishint gamma output that is detonated above ~15km will produce an EMP of significant power.
Feb 2, 2011. 7:25 AMblueeyesseto says:
if anyone can get a large amount of these used disposable cameras say 50 i am willing to pay $10 for them seeing that your getting them for free and that should cover shipping
Dec 27, 2010. 11:24 PMnutsandbolts_64 says:
If you pumped all of the power in the bank into a tiny tiny gauge wire, what would happen?
Nov 29, 2010. 3:25 PMcoindude says:
I found some high-voltage capacators from old adapters to computers and video consules and one of them reads 400v and 68 uf
Sep 7, 2010. 5:14 AMARJOON says:
fake. Your circuit is a broken one. This ciruit dont work because there is no component on it. IF there was on the bottom it would be elevated but nice intructable maybe you replaced the circuit with a new one.
Sep 4, 2010. 1:47 PMfundash says:
be carfull with this, those wires are pretty close!
Oct 28, 2006. 2:19 PMbigpinecone says:
ALWAYS, UNDER ANY CIRCUMSTANCE, DISCHARG EACH CAPACITOR BEFORE DOING ANYTHING WITH IT. I SHOCKED MYSELF WHILE MAKING A FLASHGUN, AND IT HURT LIKE HELL, WITH ONE CAP.
Sep 18, 2009. 4:23 PMdemonxkid says:
what is the best way to do this
Sep 18, 2009. 6:33 PMbigpinecone says:
screwdriver on the leads.
Sep 20, 2009. 9:57 AMdemonxkid says:
like 1 screwdriver connecting the leads or just touch 1 then the other
Sep 20, 2009. 4:44 PMbigpinecone says:
'cross the leads.
Apr 6, 2010. 9:00 AMPunkguyta says:
 With your finger
Aug 27, 2010. 2:40 PMfreerunnin1 says:
lol id laugh if someone actually did that and kept trying like "for some reason my capacitors aren't discharging"
Sep 20, 2009. 7:31 PMdemonxkid says:
is how much it holds the v or uf on the side of the conductor
Sep 21, 2009. 7:09 PMbigpinecone says:
uF is how much it can hold. stands for micro farads. V is the max voltage it will operate at.
Sep 23, 2009. 6:07 PMdemonxkid says:
sorry for all the questions but can u draw a pic or something for the complete wiring (like a schematic)
Sep 24, 2009. 1:40 PMbigpinecone says:
just go back through the instructable it's explained very well.
Sep 10, 2009. 8:43 AMhack3rboy says:
yeah i found out 330v really hurt...haha
Jan 5, 2007. 11:19 PMElectricJ says:
the scars on my left hand agree with you
Jan 7, 2007. 2:27 PMbigpinecone says:
lol now i took 3 of 'em and make a bank but i still have to test it also, do you know what the leads on a laser diode are? i have one salvaged from a boombox
Oct 13, 2008. 9:51 PMpaintballer9194 says:
allright redid this for a second time and got everything wired up properly but for some reason i still cant get the red light to come on. If anyone can see what im doing wrong with my camera circuits i would appreciate it.
1013082142a.jpg
Aug 27, 2010. 2:37 PMfreerunnin1 says:
you have to desolder the bit of metal in the middle of the board and on both the contacts underneath solder a wire, then solder the wires to a switch, hold the switch for it to charge
Aug 19, 2009. 5:36 AMjaycool1995 says:
haven't you got to push that switch.... in the middle of the board metal bit? And hold it for the cap to charge
May 23, 2009. 9:06 AMdroyce4596 says:
did you try to leave it charge longer
Dec 3, 2009. 9:33 AMObi-Wan14 says:
Does anyone knows a way to replace the disposable camera board?
so I mean what do I need to make if I don't want to use the camera board?
Thanks!
Aug 27, 2010. 2:35 PMfreerunnin1 says:
a mini transformer, a large capacitor, LED, battery pack and some switches
Apr 6, 2009. 7:45 AMtulavatalo says:
the nuke creates a emp that krashes most elektronik devices in a raduis of 10km
1-40 of 275next »

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