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Harvesting Capacitors for Backyard Munitions
Diabolus writes "This is the tale of a man, a bunch of disposable cameras, and his techniques for harvesting lots of capacitors to build a gauss gun. Insane..." A basic capacitor tutorial is probably in order.
And I bet it still won't work....
"The best argument against democracy is a five minute chat with the average voter."
--Winston Churchill
Mechanical Engineers build can crushers with moving parts.
Electrical Engineers build can crushers with no moving parts.
However, whatever the discipline, no mad science lab is complete without a Furby Testing Program.
Fire and Meat. Yummy.
fry a diode, for example
My life in the land of the rising sun.
Actually, it's not the size of the capacitor that really matters. I own several capacitors that are over 6 inches in diameter, and they are far from my most powerfull. In fact, the capacitors in camera flashes are more powerfull. You can even get capacitors the size of garbage cans (they're about 3 feet high and 2 feet across). My friend and I we're concidering buying one just for the shock factor (no pun intended). However, the most powerfull capacitor I have seen is actually no biger around than a quarter and about 1 cm high. It's capacitance ... 1 Farad (a massive amount if you know anything about capacitors, maybe it's time for better units, see prev article).
There's no sig like SIGSEG
No info on flux capacitors? Damn, guess I'll never get back to the 2030's...
c-hack.com |
isn't it cheaper to just buy caps insted of disposible cams
This place has a great supply of large high-voltage oil-filled capacitors salvaged from all sorts of stuff.
High voltage capacitors can be tough to get - Radio Shack doesn't stock many of them, and sometimes you have to buy them in bulk, which puts them out of range of most experimenters.
Microwave ovens are a great source of parts if you want to play with stuff like this, but it's worth noting that there's stuff inside microwave ovens which can kill you if you look at it the wrong way.
A full-wave rectifier made of microwave oven diodes, or a voltage doubler made with microwave oven diodes and capacitors, can be connected to an old microwave oven transformer for all sorts of fun, but can provide more voltage and current (ie. more power) than an electric chair. Be careful.
This sort of setup is great for charging up those 1uF 10kV oil-filled plastic capacitors (or doorknob capacitors) you might be able to scrounge up by looking in the right places. Oil filled caps are great because they tend to be self-healing. Blow a hole in the oil dielectric, and more just flows into place to fill it.
They're great for spot-welding.
Please don't do this if you don't known what you're doing, and I can't take responsibility for telling the wrong people stuff they can figure out from reading an electronics textbook.
Fire and Meat. Yummy.
Be careful if you try this; those capacitors hold a fair amount of charge.
My brothers and I played with some of them in the kitchen at a family gathering a few years back. One of them is in the biz, and had more used, disposable cameras then he knew what to do with. We were bored and trying to rig up something ad-hoc (as I recall, we were using whatever we could find in the kitchen--rubber bands, tupperware, etc.) Our wives were in the dining room with the everyone else, and we weren't being very structured about it.
Things were going fairly well until we accidentally shorted something. There was a loud bang, a flash, and one of us jumped back, knocking over a pile of pie tins.
All conversation in the dining room stopped, and after a moment our mother's voice called calmly: "What are you boys doing in there?"
Without missing a beat we all replied, in unison, "Nothing!"
It was like old times.
-- MarkusQ
Capacitors, Australian for bored.
Does this mean we won't be able to take disposable cameras on to planes any more?
Imagine the memo to baggage scanning technicians:
"WARNING: Any passengers attempting to take large numbers of disposable cameras on board any flight is a terrorist. These cameras can be used as a weapon by assembling a gauss gun from their parts. Call your appropriate superviser IMMEDIATELY if you have any suspicions"
Reading. You shold try it some time.
If you had, for instance, you would know he is not done collecting enough capacitors yet.
Moon Macrosystems. Sun's biggest competitor.
>Am I missing something, or is his time worth nothing?
.1 F.
Yes, you are missing something.
Car audio capacitor: 16-20 volts @
Camera flash capacitor: 330 volts @ 120 uF.
Now lets see, using the formula E = 1/2 * U^2 * C, how many joules are in each capacitor.
Car audio capacitor: E = 20 Joules
Flash capacitor: E = 6.534 Joules
Car Cap: $40 or $2 per joule.
Disposable camera: $5 or $0.76 per joule.
Camera caps are far cheaper, and this guy got them for free.
If you could be told what you can see or read, then it follows that you could be told what to say or think - BoC
Yes, you are missing the fact that most 'car audio' capacitors are 'rubbish' (to be polite) and are simply a method or removing money from peoples pockets.
For his purposes he requires an actual high capacity, high discharge rate capacitor, not an easy thing to create.
The challenge is having a VERY low ESR (effective series resistance), as well as a low inductance, and using a massive number of parallel capacitors is certainly one of the only economical ways of doing this. a LOT of care is also needed in how they are connected up to keep the inductance down.
You can, for example, by multi-farad 'supercaps', but these have charge/discharge rates in the milliamps and are used for memory backup and other purposes, you can also get kilovolt rated caps with very low capacitance, but it is very hard to get medium voltage very low ESR high energy caps, primarily because they are lethal. They are used in radar installations and a few other high energy 'toys'.
Surface area determines the "charge" (which you measure in coulombs) a capacitor can hold. The maximum voltage (which is the difference in energy between the electrons on one plate and the other plate) is a function of the dielectric between the plates (how good an insulator it is -- ceramic is better than vacuum which is better than air, etc.)
How big a spark you get is a function of the latter. How long that spark might last is a function of the former. The voltage you get out of a capacitor is always the voltage you put in (minus resistance losses). Capacitors are voltage rated because a high enough voltage will break down the dielectric and spark inside the capcitor. Some chemical capacitors, like many electrolytic capacitors, will break down with a rewarding explosion. Some, like ceramics, will maybe make a bit of a "pop" and then either become shorts or open.
I've probably made things clear as mud...
while this is cool and geeky as f*king heck... it's a bit over done.
1) you can buy capacitors for less trouble. true, large 330V caps does cost money and he is getting this for next to nothing, but i think it's better to shell out a couple hundred bux for components for that gauss gun instead of subjecting myself to hours upon hours of de-soldering and discharging capacitors and getting flashed.
2) if you *really wanted*, you can also pull caps off old TVs, or any CRT in general; and they can go up to 20kV! heck man... for self-mutilation fun, doesn't 20kV sound better than 0.3kV? (erm... becareful when you do this. those caps can hold charge for like 20 years)
3) you can achieve the same with a large (i mean gigantic) low voltage capacitor, which would actually handle more current anyhow. (car) Audiophiles probabbly know what i am talking about. there are 10-15V capacitors for your huge woofers that carry up to 10 FARADS. nope you did not read this wrong... 10F, no m,u,n,p; straight up 10F. if you wanted the high voltage, either build yourself a HV transformer (easy) or salvage one from a junkyard (you know, ignition system).
but otherwise, rock on. i would like to see the 5kJ gauss gun in action someday, preferably tested on a furby or something
My life in the land of the rising sun.
But those little camera caps are chicken feed. Try on a 2700 Farad Capacitor on for size!
I don't know anything about car capacitors, so perhaps this is a useless answer, but.... capacitor banks, rather than single large capacitors, are used in high-current circuits because they can crank out a whole lot more current a lot quicker when you have lots of small ones in parallel. This is frequently done even on small bypass capacitors in circuits -- rather than putting a few thousand microfarads on a motor, you might put several 470uF caps, for instance. The response is much quicker. So not surprisingly, this is the way you always do experiments that require frightening amounts of juice.
The streets shall flow with the blood of the Guberminky.
I remember my friend and I in 1992 to sitting around and playing with capacitors. We were even getting paid. We were hooking them up reversed polarity on a small DC power supply. They EXPLODE. We were doing small caps. Big caps would be too scary. We were putting them in the McDonalds quarter pounder with cheese styrofoam boxlets that were sold back then. Remember those? They add to the effect. I will always have that mental image of DC power leads running out of a closed McDonalds QPw/C container.
Anyways, I was responsible for 4 complete goobers and one gorgeous blonde (who really dosent have anyhting to with the story, but I just want to mention her), which was not an enviable task. They got bored on the plane to hawaii and took apart their disposable camera ... well low and behold they figured out about the only thing you can do with a broken disposable camera is shock shit or get shocked. After some dumb luck (getting shocked in the first place) and some trial and error, they figure out if you touched these leads and pressed that button youd get shocked ... so the next step was to walk around the plane getting people to hold the leads so they could shock them (someday Id like to know why you would hold two leads a 14 year old asked you to).
So one afternoon our scheduled activity was to hang out in this park because thats damn cheap :) and well now you have to know about the director ... he was this big fat, raunchy, disgusting fat fuck who happened to be one of the best directors in the nation, and he had this even fatter and even rauncher wife their two skinny (but soon to be fat kids). The wife was horrible annoying and the kids were even worse, the whole band was sick of them. Meanwhile in the park, the band was getting pretty restless, shocking eachother with cameras actually became entertainment :) So these guys I am responsible for are shocking eathother, Im hitting on the blonde (amy hays if you're out there... ;-) ), and oie of the directors sons walks up and he says "Hey what are you guys doing?" (the kid couldn't have been more then 6 or 7) One of the worst jerkoffs in my section gets this HUGE grin on his face and he says, "I'll show you. you touch this and this, and then press this button" Meanwhile I look over and see whats going on, as Im screaming "nooooooooooooooooooooo!!" in slow motion like the matrix, the kid shocks the crap out of himself and I swear he almost pissed his pants as he took off running. We never got in trouble so I dont suppose he told his father :) but we were paranoid the whole rest of the trip.
on an unrelated topic, couldn't this guy just buy a couple 1 farad capacitors? Those are pretty popular with car audio buffs, they run maybe between 100 - 200$ a piece, I think that would be so much easier then getting UV burns like this guy is describing :D
Religion is a gateway psychosis. -- Dave Foley
1. Adelaide is not yet in the U.S.
2. I can't see how his building the gun is reasonably related to the maintainance of a state militia. So the 2nd amendment wouldn't apply anyway.
Better to be despised for too anxious apprehensions, than ruined by too confident a security. --Edmund Burke
It doesn't take very long to realize you're getting slashdotted if you're paying attention.
Yeah. First, you notice that kmail seems to be taking longer transferring mail than usual.
Then, you click on a webpage link, and your usually-quick DSL feels like dialup again.
The hard drive in your webserver is scratching so much, it's hard to think; it sounds like you're compiling a kernel and making a divx at the same time, but it's pages being served and visits being logged.
You fire up top and are greeted by a whole screen of httpd daemons and CGI.
Congrats, you're being Slashdotted.
It's actually kind of fun.
Fire and Meat. Yummy.
Hey, your list has no "collect panties" step in it. Something must be a-miss.
Table-ized A.I.
First of all, there are no pictures of a gauss gun, because it doesn't exist yet. I have the parts for an inverter to charge it, but have not yet assembled it. Not having had much experience with switch mode power supplies, I'm just hoping it doesn't burn down.
For someone else's (working) effort, check out powerlabs.org
As to those who think car capacitors, etc might be better, they have a very low voltage rating (eg 15V). E=0.5*C*V^2, so even with a farad the energy isn't that great. Secondly, they are made from *thin* foil and have crappy current ratings, not much good for generating 10kA for 1ms. These are photoflash-rated caps, intended for 1ms discharge times - thick foil, good dielectric and some actual quality control.
Lastly, the capacitors will have to discharge through an inductor, even if it is only a couple of turns. Lack of voltage means the current rise is too slow (dI/dt = V/L) and so a low voltage, high capacitance bank will not discharge fast enough. Slow discharge means the ring has moved away before it receives much energy.
I'm also missing large silicon devices to actually discharge the thing. SCRs that can handle 10 or 20kA are not common and seem to cost many hundred of dollars. If anyone's got a spare one, please tell me! Otherwise I will have to make do with lots of smaller devices from surplus shops and build it multi-stage with messy triggering.
As for energy, consider 0.5*m*V^2. Given about 3 to 5kJ and about 2g of mass, you figure it out. It will be lucky to get 1% efficiency, but still. If it works well, I might have to look into firearms licensing. Big deal.
To those who say "you're a dickhead, that's lame", well, fair enough. Its not for everyone, and this page wasn't put up for the express of having it critiqued by /. bottom-feeders. I guess you could say "that's just sad", but if you're not an eleceng then you're not going to get what's interesting about this stuff.
Grandparent correct, As the owner of a few car audio shops, nothing made my day more than selling stuff to kids who thought they needed it. The sales pitch was always based on some fragment of truth then a wild jump to a $200 solution. In the case of the caps, the fragment of truth was that the voltage at the back of the car dropped when the amp sucked some current. The REAL answer is both of the following: 1: thats how electricity works 2: the effect can be minimized by making sure your connections are solid (the drop is caused by resistance, NOT the fact that your battery cant keep up to the demand.. the battery can run your starter at a couple hundred amps)
The real answers arent all that profitable, nor are they very cool, so we sell you big caps, and your friends drool with envy at your new equipment while you pretend to hear a big difference in the sound. The same principle drives the music/clothing/other industries... 'the dumbest buy the mostest'
Have you ever played with a car amp that needs 1000 watts?
No, and neither have you. 1K watts is about 1.5 HORSEPOWER. In recent years, many manufacturers of car audio equipment have been competing for your money by putting really large numbers on the cases of thier devices just because it makes kids buy them. Take the average radio.. a good one claims to do 40 watts per channel, on a 12 volt powersupply and a 4 ohm load, the maximum possible output wattage is 36.. and thats assuming a 100% efficient amplifier (which doesnt exist)
According to the ATF it is not illegal to make your own gun provided it is not a semi automatic and the person is not making it for sale and the person is allowed to possess a firearm.
A7) Does the GCA prohibit anyone from making a handgun, shotgun or rifle?
With certain exceptions a firearm may be made by a nonlicensee provided it is not for sale and the maker is not prohibited from possessing firearms. However, a person is prohibited from making a semiautomatic assault weapon or assembling a nonsporting semiautomatic rifle or nonsporting shotgun from imported parts. In addition, the making of an NFA firearm requires a tax payment and approval by ATF. An application to make a machinegun will not be approved unless documentation is submitted showing that the firearm is being made for a federal or state agency. [18 U. S. C. 922( o), (r), (v), and 923, 27 CFR 178.39, 178.40, 178.41 and
Article X: The powers not delegated... by the Constitution...are reserved...to the people
Yep, those early MiGs that outperformed our own fighters were still using vacuum tubes, a technology ten years out of date; our fighter electronics had long been transistor based.
However, vacuum tubes are highly resistant to the effects of a nuclear EMP which would have been a big concern in the 60's. The irony is that had there been a nuclear exchange the tube-based MIGs would likely have still been flyable while the 'better' American planes would have had their electronics fried.
My EE advisor in college was fond of saying:
... once."
"Any diode can be light-emitting
I stole this sig from someone cleverer than me.
1) The prefatory clause does not limit the application of the main clause.
2) "Militia" meant simply all male citizens of age and condition to be fit for military service. It wasn't necessary to be in any sort of organization, if you could potentially fight you were a member of the unorganized militia. "Well regulated", in 18th century military terms, meant "well equipped".
So the "militia" clause expressed a hope (not a law) that the citizenry would arm themselves suitably for military operations, just in case it became necessary to call on them. (And many indian wars, as well as the successful defense of New Orleans against British regulars in the War of 1812, were conducted primarily by men who joined up for just a few months.) The binding main clause says simply that the federal government should not interfere with individuals obtaining and owning "arms".
However, the US Supreme Court has always dodged cases that would require directly defining the limits (if any) on "the right to bear arms". It came closest in "Miller vs. US", where it decided that there is no right to own a sawed-off shotgun - confusingly, this decision went a ways down the road of misinterpreting the first clause, but then finally decided that the weapon in question was not covered since the military doesn't use shotguns. By the same logic, "Saturday night specials" (the cheapest, lowest quality handguns) wouldn't qualify either, because real military forces prefer weapons that don't blow up in your hand when properly used. The real problem at this point is that this reasoning seems to imply that you should have the right to buy and keep in your home a standard infantry weapon - nowadays, that's an assault rifle that can empty a 30 round clip in under 3 seconds. But we have laws not only forbidding these, but forbidding anything that even looks like them...
By the way, in Switzerland every able-bodied man is a member of the military reserve, and the government GIVES him a military weapon to take home. And the Swiss don't use them to massacre their neighbors. Is it because the Swiss are that much better behaved than Americans, or because they know the neighbors are equally well armed???
Umm, minor detail I cap of hat size wouldn't have a very high voltage rating, 500V if you're lucky. Above that, and it'll likely arc across the dielectric letting out the "magic smoke".
You can hit a million volts by placing lots of 'em in series to build up the voltage withstand. Of course, you reduce the capacitance with each series connection, so you make a string long enough to withstand the voltage and then parallel strings to get your capacitance up.
At 1MV, 5F is one *whack* of charge. Wow my mind hurts just thinking about it.
Using mostly stuff I have lying around in my garage workshop this weekend, I can fry most of the chips in the average server farm, telephone switching facility or the radios used by police, fire and emergency services. If I did it right, I can 86 all of the above at the same time.
... said someone would call me back. Not.
e p/2001/a u-221-e.html
>
h n/metalfor minghb/tabofcont/index.html ... and monitoring sales could be an early warning. If you can get the manufacturers to look for suspicious purchases it could be a good tripwire.e rovox.com// ppti2.htm lp erplast icity.htmlk er_Chronic les_II/pyro/miss2.txte mon.co.uk/anarchy/bomb/ bombs-1.html ....1 /a u-221-e.html
Indeed, I can zap all the control circuits in a modern fly-by-wire jumbo aircraft and make it do a ballistic imitation of a large brick. If I time things right, I can bring a fully fueled jet down right in the middle of San Francisco.
Can you say "9/11?" Sure you can. So here we are, nine months along, and those who are supposed to protect us are as clueless as ever.
I could create total electronic chaos and another 9/11 with a homemade, explosively pumped, flux compression generator, and I can do it with data I found on the Internet, including some very helpful stuff from the Los Alamos nuclear lab web site.
We're talking here about an electromagnetic pulse (EMP) weapon, the neutron bomb of electronic circuits. A garage EMP bomb is amazingly easy to build, especially with a 15-minute Google search.
Undoubtedly you have read about the EMP weapons we used in the Gulf War and Yugoslavia to take out air defense electronics. What you may not have read about is a 1995 incident when Chechnyan rebels used one to fry security circuits in 1995 to gain access to a Soviet facility.
Yeah, I've tried for months now to get anyone in power to care. Local law enforcement said it was not their table and to call the Feds. The FBI agent on duty in San Francisco was totally clueless
I used to work for U.S. Senator Thad Cochran. So I called one of the staffers I knew, and she referred me to the White House Liaison for Home Security. No call back there, either.
But maybe an EMP weapon sounds too much like anti-gravity boots and close encounters with Airstream trailer communities in the Mojave and that's why nobody returns calls and nothing gets done.
But realize this: the NATO document mentions the use of an EMP weapon by Chechnyan rebels. Al-Qaida includes many Chechnyans among the hard-core fighters, thus the usefulness of EMP weapons has surely been transferred to the bad guys still out there looking for an opportunity to make another big splash.
So, I couldn't just let the non-responses from the FBI and Homeland Defense be the end of the matter. With a little more digging on the Web, I located a DOE phone directory last week and called the folks who are head of security for the national nuclear labs. I actually got a call back and forwarded the information (below) via e-mail. I got a form e-mail reply, but the Los Alamos page (http://www.lanl.gov/dirac/) is still up there.
Why is the Los Alamos page important? Because it gives me a good look at an actual physical configuration of a real bomb that works. Taken together with the other web pages, it gives me an excellent chance to build a bomb that works.
Perhaps having the data out there for anyone is a victory for open info on the net, but then how easy DO we want to make it for terrorists? Where is the line between the free flow of information and discussion and giving folks easy access on how to build weapons?
EMAIL TO NATIONAL LABS SECURITY FOLLOWS
>Date: Mon, 04 Mar 2002 11:15:26 -0800
>To: marc.hollander@nnsa.doe.gov
>From: Lewis Perdue
>Subject: links
>
>Very nice chatting with you. Below are the major links I mentioned.
>
>Some detailed background on the threat can be found in a NATO Parliamentary Assembly report at:
>
>http://www.nato-pa.int/publications/comr
>
>I quoted from this report at the end of this e-mail. But particularly relevant is the following from that NATO report:
>
>"38.The possibility of terrorists using EMP weapons has been raising alarm for at least a decade among defence analysts. According to Winn Schwartau, an information warfare specialist, rudimentary EMP devices have been assembled by US Department of Defense consultants within two weeks at the cost of $500. Such devices, capable of disrupting computers, medical equipment and cars, could be placed in a van or even reduced to fit into a suitcase. Criminal organisations in Russia have been accused of using EMP devices to bypass alarm systems. According to the Russian Armed Forces, Chechen rebels might have used similar technology to disrupt Russian electronic communication equipment."
>
>As I mentioned to you, I can describe how such a device could be used to cause another 9/11-type disaster.
>
>links:
>
>THIS IS A KEY ONE: http://www.infowar.com/mil_c4i/mil_c4i8.html-ssi
>THE FOLLOWING may seem harmless, but the principles for forming metal, apply directly to an EMP weapon, both in learning how to acquire the capacitors for the construction, and because the electromagnetic pulse formation is very nearly the same.
>
>http://www.mse.eng.ohio-state.edu/~dae
>
>THE FOLLOWING ARE SOURCES FOR THE PULSE POWER CAPACITORS NEEDED
>
>http://www.nwl.com/
>http://www.a
>http://wwwcsif.cs.ucdavis.edu/~wiley
>
>
>YOU'LL WANT TO FOLLOW LINKS FROM THIS PAGE:
>http://er6s1.eng.ohio-state.edu/~daehn/hy
>
>SOME OF THOSE LINKS INCLUDE:
>
>Manufacturers of Pulse Power Equipment
> Maxwell-Magneform
> IAP Research
> Elmag, Inc.
> Pulsar Technologies (welding / crimping)
> Manget-Physik (German Mfr. of Electromagnetic Forming Hardware & MagnetoPulS® Technology)
> Kharkov Polytechnic University, Ukraine (research and equipment)
>
>Other sites related to high velocity deformation and/or hardware
>Pulse Power Equipment
> Richardson Electric (ingitrons)
> Maxwell Technologies
> Pulsed Power Technologies, Inc.
> Pulse Power Switching Overview
> Fantastically Dangerous Cap. Bank Experiments
> Aerovox Corp. (capacitor mfgr. )
> Darrah Electronics (solid state switching)
> Contents of IEEE Pulsed Power Conferences
>
>High Velocity Forming and Pulse Power Applications
> EMF Industries, Inc. (assembly with EMF is highlighted)
> Sparktec Environ mental Corp (uses sparks for water purification)
> Dana Corporation Develops Improved Magnetic -Pulse Process
> Electroimpact Home Page (mfr. of electromagnetic dent removers etc.)
> CONTENTS PAGE - RESEARCH AT SSAU (1997) (Russian welding, etc.)
> Simple Analysis from J. Krauss Electromagnetics Book
> Robert Hahn at IWF, Technical Univ. of Berlin (in German)
>
>IF YOU WERE DESPERATE FOR C-4 or Semtex for your EMP device, and didn't have a source for the ready-made stuff, you could try here:
>
>http://www.phreak.org/archives/The_Hac
>http://www.strange-days.d
>
>FINALLY
>
>New material continues to be posted on the Web. If you do a search for "flux compression generator" you will find more listings than just the ones above.
>
>
>NATO Parliamentary Assembly
>http://www.nato-pa.int/publications/comrep/200
>
>37.Yet another threat seems more imminent. As Ehlers indicated in his report, computer systems and all electronic devices can be seriously damaged by weapons producing electro-magnetic pulses (EMP). High Power Microwaves (HPM) or EMP bombs and High Energy Radio Frequency (HERF) guns can radiate intense pulses of electro-magnetic energy capable of severely damaging computers, radar and all electronic equipment. They can even destroy circuits, microprocessors and other components. These weapons are well-known in Russia, where extensive studies were conducted during the Cold War. The US Air Force used EMP and HERF weapons successfully in 1991 against Iraqi radar installations, and in 1999 against Yugoslav electronic infrastructure.
>
>38.The possibility of terrorists using EMP weapons has been raising alarm for at least a decade among defence analysts. According to Winn Schwartau, an information warfare specialist, rudimentary EMP devices have been assembled by US Department of Defense consultants within two weeks at the cost of $500.
Such devices, capable of disrupting computers, medical equipment and cars, could be placed in a van or even reduced to fit into a suitcase. Criminal organisations in Russia have been accused of using EMP devices to bypass alarm systems. According to the Russian Armed Forces, Chechen rebels might have used similar technology to disrupt Russian electronic communication equipment.
>
> 39.In his book Cybershock, Schwartau considers some possible effects of a well-orchestrated EMP attack upon Western infrastructure:
>
> Wall Street or other banking systems can be attacked, causing repetitive failures resulting in financial losses. Also past records can be wiped out by onslaughts of electromagnetic pulses; aircraft avionics and guidance systems can be overloaded by targeted HERF, causing potentially deadly conditions; medical equipment can fail under the attack of intense energy spikes, putting human lives in danger; communication nodes can be burned out by intense microwave radiation; municipal emergency services can be made inoperable by debilitating wide-band microwave jamming; power lines and transformers may serve as efficient conductors to transmit huge current to victim businesses and sub-stations, causing regional black-outs.
>
>40.The ability to build EMP weapons is apparently quite widespread, yet there are no international controls over the import and export of the related technologies. Defensive techniques, although in some cases expensive, have been partially deployed in the public sector (especially to protect military assets), but remain extremely rare in the private sector.
If I had access to high explosives I'd just blow up the thing I wanted to destroy and save myself the trouble of screwing around with EMP. Hell, if I had a nuke and wanted an EMP bomb I'd put it on a rocket (if you can get/build a nuke you can get/build a rocket too) and detonate it in the ionosphere and generate one hell of an EMP pulse via nature! This actually happened once in a high altitude nuke test to Hawaii.
It is by the juice of the coffee bean that thoughts acquire speed, the teeth acquire stains. The stains become a warning
Take the average radio.. a good one claims to do 40 watts per channel, on a 12 volt powersupply and a 4 ohm load, the maximum possible output wattage is 36
The radio you describe is the same bridge output amplifier that a few years ago was rated at 12.5 watts per channel, or 25 watts for 2 channel or 50 watts for 4 channel. It's the same voltage into the same load. Nothing has changed but the numbers.
Because people tend to by things by comparing the fancy numbers on a spec sheet, lots creative writing has been done to seprate fools from their money.
#1 Rate peak power instead of RMS average watts.
Explaination; Music is not DC heating power. If you take the maximum DC voltage and figure the power based on load resistance, you can get a high number. In the example given, 40 watts was tossed out. It was pointed out that that number refuted with a supply of 12 volts. It wasn't figured at 12 volts. The charging system provides about 14 or more volts. Redo the math with this number.
An audio waveform is not a sine wave. The peak possible voltage is not provided to the speakers 100% of the time. In the '70's some good stuff was rated at RMS power at a specified distortion level. In the above case, 40 watts is only possible with the engine running and the speaker voltage never leaving peak values. In short a very distorted square wave output. Not pleasant music in my book. A 6 Watt RMS rated amplifer at 0.1 THD is a much more powerful amplifier. My favorite amplifier is rated 25 watts RMS per channel at 0.04% THD into a 4 ohm load. Some amplifiers are rated to provide their rated output only a very low speaker impedances. 2 and one ohm are common. Almost half the power rating for these as they can not provide the voltage needed to properly drive rated power into a 4 ohm speaker. Needless to say, that rating will misslead most newbies in the audio field. The don't understand why my 50 watt amplifier uses 8 AWG wire with a 20 amp fuse. They are also supprised when I connect a scope and show it provides more unclipped peak to peak voltage to the 4 ohm speaker than most amplifiers rated 200 watts. Yes the honestly rated 25 watt amplifer is a bigger and higher power amp. That rating is not a peak power rating. Learn to compare apples with apples. Is the spec peak or RMS? Is that rated into 4 ohm, 2 ohm, 1 ohm? Is that rating guaranteed at 11 volt supply, or does the amp need to be under the hood getting 14 volts direct with no power distribution system to provide voltage loss due to resistance and distance? If you have a 200 Watt RMS into 4 ohms rated amplifier, I'll be looking for serious hearing protection! The car audio market is "let the buyer beware". The specs on paper are deliberately missleading. Borrow a scope and a dummy load. Find out how much Peak to Peak voltage the amplifier will deliver before before clipping occures. Don't buy anything that will not put out at least 40 volts for a small amp and 80 volts for the super thumpers. Half these values for brige mode amps. I have seen stuff rated at 120 watts that are powered by an 8 amp fuse. 12 X 8 is only 96 DC watts in at the point the fuse will blow. (commenly spouted spec for cheap underdash EQ-boosters) Some power is lost to heat in the audio conversion from DC. How much is left for each speaker? How are they expecting to get 120 watts out with only 96 watts maximum in? That rating is not RMS average music power! There is some honest stuff out there. However bring your pocketbook. It isn't cheap!
Now onto the function of caps. Music has it's peaks and valleys. The resistance of the electrical distribution system is finite. It includes the wire, battery internal resistance and alternator internal resistance. Current draw over a finite resitance provides a voltage drop over the resistance. This is well defined in ohm's law. The current drawn by an amplifier is not constant. It varies. Simply the more the current draw over a fixed resistance the more the voltage drop. Because of this the voltage drop varies as the current drawn varies. The wiring can have it's resistance reduced by using bigger wire, battery resistance can be reduced by adding more batteries (and placing one close to the amp to shorten the wire from battery and amp).
To provide the maximum voltage to the amplifier at a music peak, the loss in DC voltage at the peak current draw can be acheived by providing the peak current from a local capicitor instead of through a long wire to the trunk. A big capacitor can provide the short duration high current the amplifier demands on a music peak, preventing the high current peak on the DC distribution system and it's associated peak voltage drop. A good scope will tell you in short order if the money is worth it. Watch the voltage drops on high power music at the amplifier with and without the cap. Saving a 1/2 volt peak drop may make a diffrence in a competition, but most people won't need it. Don't even consider adding a cap if your music peaks drop the supply voltage at the amplifier less than 1/4 volt. You don't need it.
The truth shall set you free!