Added: 4 years ago
From: bobdavis321
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  • AC or DC caps? I have 4, 475 volts AC Capacitors wich have 45uf each, i was thinking about but them in serie for something around 1800 volts and 45uf, will that generate some power or does it need to have moore Farads?

    Plzz Answer!! Best Regards

  • Who gives a shit about weather It's powerful or not. Most people on Youtube are too lazy to get off their fat ass and build something. Instead they just go to a video and call it crap just because they can't do it or they are too lazy to do it.

  • my potato gun has a very much bigger damage...

  • dude if you can help you will be life saver i am making my first coil gun and i need to find out how to charge my capacitors they are just like yours 400v each but i have 10 of them, but i havent put them into parrel next cos i am sure how and what it does :L pleassee help :L

  • @coreyisbuzzing - Put 5 in series for 2000 volts then use an old MOT for a power supply.  Any higher voltage and SCR's cannot handle it.

  • @bobdavis321 Are you saying that it is better to connect the capacitors in series rather than parallel?

  • Hey, next time, start shooting video when ps is working already. We don't have your setup, and it doesn't really matter to us what you have to do to fix supply. If you are making a video, please don't waste my time with showing how your ps doesn't work and explaining how you fixed it. JUST SHOW VIDEO OF IT DOING WHAT IT IS SUPPOSED TO DO! you get dislike for that, i hate waiting to see video I'm trying to watch.

  • @scoobygoo44 - I like to show people that i have problems too. I wish the camera was running when I blew up a volt meter......

  • @bobdavis321 The showing mishaps and whatnot gives it a more personal feel. Almost like we are experiencing it at the same time lol. Personally I like that aspect of it.

  • @scoobygoo44 it's a video of something technical. Therefore he must explain. Not patient? fast forward.

  • I am not experienced in this area but from what I have seen in other videos, you could probably penetrate a steel box with that kind of voltage if you had more stages.

  • Cool PSU bro!

  • now make a sniper with that and see how far itl shoot

  • You're using the wrong kind of projectile, you need to use a spike or a sewing needle/needle.

  • That was ok.... You should either stop making coil guns or ramp up the farads and joules. and kick some good science ass. =]

  • shitttt

  • WunderWaffe DG-2!

  • wtf is that your life?

  • do you just need a transformer only to charge capacitors (plus battery ofcourse)

    can you tell me how many volts, amps, farads, and whatever else there is that i need for the transformers,resistors,diodes,­relays,capacitors,and all that stuff? I am pretty much clueless on what to use. (im on attempt two of my first coilgun)

  • Hey they fixed YouTube so I can reply to comments? I use a Microwave oven transformer, a diode and a resistor to charge the caps.

  • @bobdavis321 can you tell me what the diode does and why its needed? also with the resistor? Sorry, i dont know much

  • The schematic is on my blog at bobdavis321 dot blogspot dot com under high voltage stuff I think...

  • NICE!!

  • How did you make the coil? i.e. what guage wire, how many turns, etc? Have you experimented with different types?

  • I might have missed it, but what exactly is the gun firing?

  • @Fandalg its either a small metal rod or a small metal ball bearing

  • you should place your coil higher up the barrel for a larger amount of pull.

  • You only use 1 hv diode and resistor? geez i cant even begin to imagine how much they heat up. Also, how do you have the cap lined up? Do you have all of them in parallel or a series-parallel configuration?

  • Series-parallel combination.

  • @bobdavis321 400v Caps ea? How many microfarads?

  • I think they were 5,700 each?

  • have you got the circiut for biulding this 8 capacitor charger

  • I use a microwave oven transformer a hv diode and a resistor.

  • omg it hit that can hard dude!! how do u do this shit

  • GeeK! WTF ARE YOU PPL DOING, SOMEONE NEEDS A GIRLFRIEND, AND PPL DONT HATE, CAUSE OBVIOUSLY HE DOES...ANYONE THAT REPLY'S NEGATIVE TO THIS ALSO NEEDS A GIRLFRIEND......TRYING TO DEFEND THERE GeeKDOM

  • I bet your girlfriend is Megan Fox. Just try to think around some corners: You like your flatscreen and MP3 player right? You must think dudes like Eminem or 50Cent invented this shit right?

  • So doing the make out in public, having kids at a young age, and overall just being the norm is a life? Get real.

  • @McDeeViouz I got a wife, more then you´ve got?

  • @ McDeeViouz its people like you that work for us, we understand this so we make more money and develop great things, if you think that all of your electronics design themselves you may want to rethink your dead end job.

  • you could make it shoot a b.b. into a primer on a a rifle bullet or a shotgun shell.

  • @pippeykillz or you could spend alot les time and effort on a rubber band and cap...

  • all that with a single stage? pretty sweet! (although I can't imagine the charge on those capacitors. geeez)

  • Its Single stage.

  • Nice. I got a 9400 joule, 2000 volt coilgun. You got a suggestion for a good power supply?

  • For 2000 volts I would use a microwave oven transformer.

  • see if you can fire something the size of a .50cal

  • Alot of power, but no penetration; sharper projectile, same power (unless you'd like to reuse your power supply) :)

  • Check out my other videos. I shot a nail through the can.

  • can i just use AC ?

  • I Doubt it.

  • I read somewhere that you could use a voltage multiplier with AC to get enough power.

  • im having trouble finding a transformer that is 300 volts

  • I used a voltage multiplier.

  • eck out my blog under bobdavis321 at blogspot. There is a schematic there somewhere.

  • ok ill search for one

  • You need a smaller, sharper projectile. Maybe get nails and cut the heads off so you just have the point and the shaft.

    The faster the projectile, the more energy. You want a small, heavy (for it's size) aerodynamic projectile that can move really fast with good momentum behind it.

  • unless u just want to punch hard rather than pierce, then it goes slow but hits heavier

  • Hey bobdavis, have you ever tested to fill a can with sand? Why I'm asking is because it requires more from the "slug" to travell thru the entire can (if filled with sand). It's good to test / set power.

  • of metal from the wire in both the thick and thin wire (assuming the overall coil is the same size for both).

    B = u* N * I / L

    so u is a constant, ignore it. Well we already said resistance is going to be approximately the same because the volume is approximately the same, so assume its the same for both and ignore it (current will be slightly slightly less with small gauge wire). OK so all you have left is N / L. 

    You want to have more individual loops and a shorter Length to have

  • no no no, the thinnest wire you can get without melting it is the best wire size. The formula for magnetic field of a solenoid is (magnetic field is B, resistivity of the material is u, N is the number of loops, I is the current , and L is the length of the coil).

    So notice a few things, i said resistivity, not resistance. resistivity is a constant for any material. The reason it doesn't matter (simply) is because your using approximately the same volume

  • so for a solenoid, are the highest awg sizes the best? like 30-40 or so? and what is 100uf and 5KV. im guessing KV is kilaVolts

  • I am using 14 awg wire. Bigger wire, smaller AWG, makes more current flow and a bigger magnetic field, to a point. 5 KV is 5,000 or five thousand volts.

  • so if you ahve a very thin wire and a thick wire(your size) and you wound them up so you have the same mass of wire. the solenoid with the thicker wire will shoot faster?

  • It all depends on things like voltage and current and capacitor size.

  • if my camera flash charger came with a 330 volt capacitor and i hook up a 200 volt capacitor instead will it overload the capacitor or turn off automatically thanks?

  • Most likely it would overload the capacitor and damage it.

  • ok thanks for the help i truly apreciate it i have 200 volts 769 joules in 2 caps :)

  • If the capacitors are identical you can put them in series so they would handle 400 volts.

  • well theyre not identical but same voltage just diffrent joules there ceramic if that helps

  • They have to be identical to put them in series to handle twice the voltage.

  • also great news for me i just checked my old computer monitor power supply i have (unoperational) and found a ceramic 400 volt 562 joule capacitor yeah me:) lol haha 17 year old messing with high voltage parents dont like it but they know im smart and do it SAFELY (safely in caps for those of you idiots out there) but anyways thanks for the help earlier appreciate it maybe sometime i can help you doubt it though you are probably way smarter then me lol

  • May I ask for schematics?

  • excellent, i enjoyed every second of that. 5 stars

  • You should see what I am working on now. 100uF at 5KV!

  • well you could make it portable

  • dude you need microfusion cells, like in fallout 3

  • Haha +1

  • You need Microfusion cells dude.

  • You need microfusion cells.

  • great vid definatly 5 stars

  • Thanks!

  • where'd you find the capacitor charge level gauge?

  • Its just a volt meter. I used a digital meter in my newer model.

  • where'd you hook it up? directly on the input wire from the capacitors?

  • Across the capacitors.

  • fix your shit and then make a science video homes

  • how long do you htink it will be until armies start experimenting with portable coil guns?

  • They have been experimenting with them. The idea is that they can fire faster.

  • their likely not gonna use them, railguns give better performances for the same size and weight, the thought has come up, but as said, railguns made them obsolete for the military.

  • i was expacting hole in it, NO GOOD

  • this can easily work with a readily , rechargeable energy source... i used a 2.5million volt tasor i got for $130.00 ^-^ ... heads up this one could probably kill a dude... yes the tasor is rechargeable, it plugs right into my wall lol

  • those things output almost 0 amps

  • Nice work! I want to make one of these

  • dont drop that in the bathtub when your in there:)

  • what are the specs on your caps? uF/wv ?

  • hey if i were to build a coil gun what would be the minimum voltage at which it would work.

    say if i had like one out of a straw and like 50 feet of wire because i don't like high voltages very much even though i know alot about it

  • You can get one to work at 24 volts, just use the coil and plunger from a doorbell.

  • Is it better to use a metalic barrel or a non conductive one like a straw?

  • I think a metal barrel would block some of the magnetic field.

  • Use a non magnetic substance like a plastic straw. The magnetic energy would create fluctuations in the metal barrel and ruin the thrust even if it can throw the projectile

  • capacitor limit the amount of power on these, I have experimented on these. I learned that adding so much caps will no longer make the bullet any faster. You can get the same effects just using switches without capacitors. I was thinking about precisely timed stages, using sensors, and transistors. My goal is to make the projectile go as fast as a bullet.

  • I have a coil gun I made with a capacitor bank of 330v 880uf. I haven't done a shot with a full charge yet, and I can get a nail to go through the entire can. For some reason, I get better penetration without anything behind the can. My coil has ~30mm length, 8 layers of 22 gauge wrapped around a straw I use as a barrel. What are your specs?

  • Back then I was using a 1/2 inch by 1 inch bolt. The coil was three layers of 14 gauge wire, about 30 turns, on a 3/4 inch tube. In a later video I used a coil wound on a pencil and a nail to shoot through a can.

  • I was thinking about using transistor so I can switch the current of much faster than a capacitor, and using several stages. I have been doing the same thing for 3 years now trying to make a gun that uses electricity. I want it to go like a bullet from a gun.

  • Where did you source the caps? was it a defrib or something?

  • I bought a box of them at the Rochester Hamfest for $65. I have tried defib capacitors and they are lame.  Their 30 uF does not compare to 3,000 uF. Maybe I will post the video? The advantage of defib caps is that they handle 6 KV!

  • this is awesome, doesnt look to complicated either

  • 800 volts= capacitor energy or battery energy?

  • Capacitor, it delivers the power for a shorter time than a battery.

  • yeah yeah but it that the ammount it charges up to? or what it starts at?

  • It starts at 0 and charges up to 800 volts.

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  • bad ass power supply

  • Shooting cans is lame!! shoot a pig!!

  • Sorry no animals were harmend or will be harmed in the production of these videos.

  • just a sugestion, I notice the wire you use to connect the coil to your power supply "looks" quite thin. In terms of resistance, this could effect the effectiveness of your setup. most of the pulse could be dissipated as losses. I believe you can get better results using some thicker cables, otherwise thats a neat looking power supply, im quite impressed. keep up the good work

  • you need to find a way to utilize that button from a far distance, I would look at xbee and the arudino or something like that ;)

  • that power supply kicks ass o_O

  • would be more impressive if it looked like a weapon

    firstly, how many feet per second does the projectile travel at

    second, what is the weapon's effective range

    third, how accurate is the weapon at a distance

  • No idea.

  • Those kinds of things are important to determine the effectiveness of a weapon, while figures about how many volts it uses are impressive, more important is how effective it is as a weapon. And a suggestion, use a longer barrel and a fin stabilized projectile, rifling the barrel wont work for a coil gun as rifling works by having the partialy molten bullet follow the grooves in the barrel, a cold weapon like a coil gun wouln't have a partialy molten bullet.

  • WOW! Freaking awesome power supply! Nice!

  • edit out the first two minutes of video. no one wants to hear you talk...

  • a bigger coil gives more power right?

  • Its not that simple. A bigger coil would draw less power so the field would laast longer. A smaller coil draws more power so the caps discharge quicker. Its a compromise.

  • You wouldn't necessarily need larger caps, but the caps you have should be optimized for the coil. The larger the capacitance the longer it takes to discharge, which could reduce velocity. I have 6x 1100uF/450VDC caps in my railgun, and I run them in series (halves capacitance, doubles voltage). The equation for energy is e=1/2cv^2. If you half the capacitance you get 2x less enegry, but since voltage is squared you then get 4x more. So, more voltage/less capacitance = more total energy.

  • I have 6 x 1100uF/450VDC for my railgun, they look about the size. You might find it more useful to run the caps in series, as that increases the voltage (but lowers the capacitance). The equation for energy is E=1/2CV^2, (c=capacitance), and since voltage is squared, that means that if you double the voltage you get 4x the energy. Also, the more capacitance the longer it takes to discharge through the coil, could reduce velocity. You can get some HV (4000+) x-formers from old microwaves.

  • I'm sorry to be a skeptic but with that much power you could get a hell of a lot more velocity out of the gun. Perhaps if you made a two stage and had larger capacitors you'd get somewhat better results.

  • Back then I was shooting a 1/2 inch by 1 inch bolt. In later videos I used a nail and put something behind the can and was able to penetrate a steel can at 300 volts.

  • Ah, that makes more sense. Good to hear.

  • not to sound like an arse or anything but my friend made a coilgun for his A-level physics coursework which had only 2 of those similar size capacitors and an ever-so-slightly bigger coil and it could shoot through 2 coke cans at the same time. doesnt seem to make any sense since you've got alot more capacitors than he did. try making a longer/thicker coil and you might see an improvement.

  • its great

  • Tell me how to make one of these!!!!!iiiii :DDDDDDDD

  • see my blog at bobdavis321 on blogspot

  • also , u could make long wire and use it as a gun for fun :D

  • lol ur voice is like the 1 from gta san andreas the mission that u had in 2nd city with burklies or something (toys) :DDD

  • How many joules does it put out? It doesn't look like much since the projectile didn't make it all the way through.

  • shooting boxes is lame...

    dont you think cans is also lame?

    With that power you need to shoot the concrete block!!

  • many energy but less wire

  • Use a hockey puck style SCR. That is what is used in Capacitive Discharge stud welders. Dont need to worry about heat sinks, but you do need to make sure there is enough pressure squeezing down on the SCR. These SCRs rely on the pressure of the mounting clamp to hold their internals together.

  • how many amps can that thing put out with the 8 togethger?

  • Enough to fry a 100 amp scr. I suspect a surge of around 1000 Amps, but I do not know for sure.

  • damn. ive been testing the one i just built with only 50 amps and its been going good. but 1000 sounds like something i should try sometime. about how long did it atke for you to put it all together.

  • It only took a few hours to start with. It had 4 capacitors back then. I have been improving it for a year now.

  • 1/3

    The ampere a capacitor (capacitor system)can deliver depends on the internal resistance of the capacitor(s), also known as ESR (Equivalent Series Resistance). Electrolyte capacitors have a tendency to have a "high" ESR compared to other types of capacitors, but we tends to use electrolyte capacitors anyway becouse of the high charge capacity (Farad).

  • 2/3

    I got 1 capacitor which is 1.000.000 uF the size of a 2 liter cola bottle, it has "low" ESR, just a capacitor people use in cars audio systems. I also has a 1.000.000 uF the size of my thumb, for CMOS backup. This one has a "high" ESR, preventing the capacitor from deliver currents above 0.03 Amps(which is more than enough for a CMOS circuit to maintain data storage).

  • 3/3

    When you want to make a coilgun you want to have a high current so you have to battle the ESR in the capacitor system. An easy way of doing this is the couple the capacitors in paralell. Coupling capacitors in series kinda gives you a higher voltage of the charge but you will lower the maximum current the capacitors can deliver becouse you have increased the ESR.

  • you have to connect those 3 capacitors in parallel to get the most of the cap.

  • how would you connect 3 capacitors together?..i want to store as much power as i can, im trying to make a tazer...but i want more power..could anyone help me out?

  • Yipes! You do not want a lot of current in a tazer, you could kill someone!

  • in series

  • *facepalm* I'm all for free sharing of knowledge and such, but I'm betting somebody is going to get hurt.

  • used disposable camera.

    Google it.

  • A camera flash is what I started with too! The coli goes in series with the flash. Then you add more capacitors.

  • how much did one of thes Capacitors coast you and where did u get them

  • I bought a box of them at the Rochester HamFest for around $67. They can sometimes be found on Ebay.

  • this is actually more interesting with the information in my opinion, I mean, do you just want to watch people do awesome things while you sit on your ass, or do you want to find out how to do it?

  • can you use a taser for a power supply?

    i was thinking either a coil gun or maybe a capcitor gun

  • I think a taser would be too high of a voltage and too low of a current. You need lots of current.

  • soooo, a car battery?

  • A car battery would not get enough current to flow unless you used a larger gague of wire. The voltage is too low. -Bob

  • soooo, plug it into an outlet?

  • There is not enought current in outlets due to the circuit breaker. You need to charge capacitors first.

  • so get 50 car batteries, and run them through a step up transformer?

  • 10 car batteries would give you 120 volts, that would make a good coil gun. You might be able to charge them using 110 volts from the outlet but there should be a resistor to limit the current and overvoltage protection to prevent them from being overcharged. I was using 800 volts.

  • im only 14, so i dont really do anything huge, just simple things, like small tesla coils. not that i dont know anything, im capaple making nukes, just would never do it unless i was hired by the millitary, i just dont have money to bye neon sign transformers, flybacks, etc. is there any way i could make this for an affordable price?

  • I started with a couple of big capacitors removed from an old telephone system power supply. Basically all you need is a voltage multiplier and a big capacitor or lots of small ones. I have a 300 volt model that uses about 30 small 470 uF caps.

  • are you sure its watts, and not amps? because, i could probably make this esily if it was watts. if it were watts, then i could use a the thing you screw light bulbs into (i dont know what its called), and i'd have a coil gun.

  • It is current that you are after, the higher the voltage the more current flows through a coil. To deliver a lot of current big capacitors or batteries are needed.

  • he couldve just recorded all the good footage and deleted the bad ones therefore making this vid less boring

  • i can tell a lot of money goes into your coil gun because you have generic root beer!!

    just kidding lol

  • If there is ever a zombie outbreak, i'm going round your house

  • Are magnetic guns effective against zombies?

  • I hope so =], or you could just zap em with the capacitors, whichever is best ^-^

  • Well fill it with very small Nail Bits and there are no zombies to worry about even if the ywork without head^^

  • Watch out, this guy's got Ninja shoes on!

  • You're going to destroy nation with all of these things you do with this capacitor bank... Try putting the coil at the complete back of the barrel, and putting a magnet (try a neodymium) to it'll repell... Oh my god that would go through soooo much stuff!!!

  • Dont use a resistor! it will keep burning out. use a water resistor with high edges. it will boil but it will not be damaged. and wire should not melt if they are use biger wire.

  • A water resistor, that is a new idea for me. Another solution is to use a light bulb.

  • I'd like to do this with multiple coils and banks of caps sequentially fired.

  • very nice. try just shooting the cinder block, see how much damage it does. me and my freind are currently working on one, it uses a shitty 80 uF capacitor @ 330 volrts, 3 layer coil @ 1 inch long. dunno how well it will work, or if it will at all. lol but nice job , really clean and organized.