kevin gilmore Posted April 28, 2008 Report Posted April 28, 2008 So I was out doing errands yesterday and came across a garage sale with lots and lots of electronic stuff. Highly unusual. The guy's wife had recently passed away and he was getting rid of all of his collection over the years. Suffice it to say i bought one standard corvette's trunk worth of stuff, and will go back and get more today. Anyway he had these capacitors i had to have. He said they were for a top secret military project in the very early 1960's. There are no labels on the things, or they came off years ago. He said they were 1000 uf/5000 v caps. So i brought one into work and sure enough it really is almost exactly 1000 uf. He said they were teflon film caps. It weighs more than 20 lbs. Absolutely the perfect OTL output cap for dynamic headphones. Mikhail is going to need a bigger chassis. He had a total of a dozen of them... If i get the rest i'll send a pair to mikhail as a present. http://gilmore.chem.northwestern.edu/bigcap2.jpg Trying to find a ruler now, but my micrometer says its 7 inches in diameter. Quote
909 Posted April 28, 2008 Report Posted April 28, 2008 that huge red cap and you getting your hands on more reminds me of something a bit like this... Quote
kevin gilmore Posted April 28, 2008 Author Report Posted April 28, 2008 Can't be a 5000 volt cap. That would be too much energy storage. Starts to spark at 1400 volts. So at a 1kv rating that is still 1000 joules. More than twice as much needed to stop your heart. Quote
n_maher Posted April 28, 2008 Report Posted April 28, 2008 And this after I finish the Menace. Nice score Kevin! Quote
dc Posted April 28, 2008 Report Posted April 28, 2008 is that the only way to measure max voltage of a cap? Quote
kevin gilmore Posted April 28, 2008 Author Report Posted April 28, 2008 Without any manufacturer markings or any other information, figuring out the max voltage is tough. Could saw the thing in half and measure the thickness of the dielectric (not going to happen). Or try and guess what the hell someone would do with such a thing. 1) could be the output cap for a VLF transmitter. Just one would be good for 100kw. AM radio <1mhz possible... 1000 volts into 50 ohms... 2) could be the output cap for a very high rep rate xenon flash. after that i'm out of ideas. Quote
Duggeh Posted April 28, 2008 Report Posted April 28, 2008 Secret Military Project eh? I think Westwood went there. Quote
deepak Posted April 28, 2008 Report Posted April 28, 2008 bigcap2.jpg That's a fitting filename Quote
pmillett Posted April 28, 2008 Report Posted April 28, 2008 Secret Military Project eh? I think Westwood went there. Actually, I'm gussing you're not far off the mark. Those are waaaay cool caps. I bet they cost thousands of dollars each. My guess would be some type of particle or laser weapon research project - or maybe even an electromagnetic gun. Both require massive peak currents. I worked at a particle accelerator for a while (another story) and to fire the linear accelerator we had banks of big caps... Pete Quote
pmillett Posted April 28, 2008 Report Posted April 28, 2008 http://en.wikipedia.org/wiki/Coilgun http://en.wikipedia.org/wiki/Railgun Quote
bhd812 Posted April 28, 2008 Report Posted April 28, 2008 Given the size of it and knowing it was from the 60's i would say another 400 hours or so of burn in and it should really open up! Quote
kevin gilmore Posted April 28, 2008 Author Report Posted April 28, 2008 Given the size of it and knowing it was from the 60's i would say another 400 hours or so of burn in and it should really open up! I think you are right billy. Maybe i'll give one to ray and he can build it into a portable tomahawk. If he scales everything up to the size of the cap, it would be very impressive. And need a fork lift to move. Its not really the right form factor, so he will need two in series. Quote
Dusty Chalk Posted April 28, 2008 Report Posted April 28, 2008 So was it still holding a charge before you connected it to anything? Quote
Smeggy Posted April 28, 2008 Report Posted April 28, 2008 Particle beam weapons obviously. I'm not sure I'd really want anything on my head that was connected to those, and I certainly wouldn't want to lug it around to meets! On the bright side, you can now say your amp is not only Mil Spec, but Top Secret Mil Spec. Quote
recstar24 Posted April 28, 2008 Report Posted April 28, 2008 And I thought these were big: 250uF polyprop soybean oil - 1000uF teflon film = Quote
Smeggy Posted April 28, 2008 Report Posted April 28, 2008 And I thought these were big: 250uF polyprop soybean oil - 1000uF teflon film = Oh but it's sooo pretty. I'd like one even if just to look at *sigh* Quote
Augsburger Posted April 28, 2008 Report Posted April 28, 2008 Sheesh! All I ever find at garage sales are Elvis paintings on velvet. Quote
kevin gilmore Posted April 29, 2008 Author Report Posted April 29, 2008 So was it still holding a charge before you connected it to anything? thats what the shorting wire is for. And after charging it and discharging it, and the shorting wire on for 4 hours, i took it off, and within minutes it was over 100 volts. Quote
philodox Posted April 30, 2008 Report Posted April 30, 2008 Oh my god... I want 4 so bad. Any chance you need a kidney Kevin? Quote
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