peterbak@microsoft.UUCP (Peter BAKO) (01/11/90)
I would be interested in creating a Xenon flasher, but I have never used one before, nor have I had seen any schematics for one. Does anyone in netland know of any sources for wiring one of these things up, or better yet have one they can send me? Thanks... Peter Ps. If you could please Email me instead of posting. This sub- board is not one of my regulars... -- (*)-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-\/-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+(*) ( UUCP: peterbak@microsoft || Is this all that I am? Is there ) ( CompuServe: 71170,1426 || nothing more? - V'ger ) (*)-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-/\-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+(*)
spt@waikato.ac.nz (Simon Travaglia) (01/16/90)
By Xenon flashers I assume you mean strobe lights? ETI regularly (annually, bi-annual) publishes a circuit book with the BEST OF it's past circuits. There is usually always a new and improved circuit for a strobe light there. The whole thing is fairly simple, uses recified mains (noisy as you like) to charge a cap, then an SCR to trigger the discharge of the cap into a coil, which steps the volts up to 4k or so. Words of warning: Be bloody careful with these things they can give you a nasty shock. (Even when they are turned off, because of the large cap - I got a belt off one and would not like to repeat the experience. Always check your earths twice. I don't know whether it would kill you or not, but it IS sufficient to make you sit down. -- %SYS-E-NOSIG, signature file mutilated by foreign power. %SYS-I-DEFSIG, using emergency signature Simon Travaglia, University of Waikato, Hamilton, New Zealand. Disclaimer: "Sorry about that cheif!"
henry@utzoo.uucp (Henry Spencer) (01/18/90)
In article <1990Jan15.214459.6707@waikato.ac.nz> spt@waikato.ac.nz (Simon Travaglia) writes: >Be bloody careful with these things they can give you a nasty shock. >(Even when they are turned off, because of the large cap... The high-end Fuji "disposable cameras" have a tiny little flash unit built into them. I took one apart to see what was inside. Being careful, I shorted the flash capacitor with a screwdriver before exploring too deeply. I'd expected it to have some charge on it, but the great fat spark and the nasty loud CRACK was quite a surprise. No damage, just startled me, but I'm glad it was a screwdriver and not my finger. Nasty shock is the word for it, especially with a larger one... -- 1972: Saturn V #15 flight-ready| Henry Spencer at U of Toronto Zoology 1990: birds nesting in engines | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
erc@khijol.UUCP (Edwin R. Carp) (01/18/90)
In article <1990Jan15.214459.6707@waikato.ac.nz> spt@waikato.ac.nz (Simon Travaglia) writes: >By Xenon flashers I assume you mean strobe lights? Radio Shack also sells a little battery-powered Xenon strobe quite cheap. >Disclaimer: "Sorry about that cheif!" Is this a deliberate misspelling? -- Ed Carp N7EKG/5 (28.3-28.5) uunet!cs.utexas.edu!khijol!erc Austin, Texas (512) 832-5884 "Good tea. Nice house." - Worf "The best diplomat I know of is a fully activated phaser bank." -- Scotty
eachus@aries.mitre.org (Robert I. Eachus) (01/20/90)
As long as we are on the subject... Xenon/Argon/Neon tubes when
"properly" driven can do some amazing things. The good ones are
almost indestructable. (They do evenutally fail by producing Xenon
TriOxide (XeO3) which eats away the electrodes but that takes hundreds
of hours run literally red hot. (If the bulb only glows red for about
ten seconds after use, you are not overstressing it.) One project I
worked on took a standard GE flashlamp designed for commercial
photographers (rated at 7 watts average max.) and ran it with a 15KHz
pulsed DC power supply at 2 kilowatts. Much better (and cheaper) than
photofloods for high-intensity TV studio work. (Now mostly quartz
halogen.)
The largest flash lamp I ever put together was around 20 Kjoules
(yes I've seen bigger, but this was my personal record. The capacitor
bank was about four feet square -- Maxwell mylar capacitors 100
microfarad at 4 Kilovolts each. The pulse from this beast was not
particularly sharp (1/2 intensity width about 1/2 millisecond) but boy
did it light the room. When we fired it we would (already wearing
protective glasses) turn and face away with our eyes closed. You
would still get after-images. At eight feet the light was about 1000
times noon tropical sunlight. One time the wire to the trigger circut
came loose. Reattaching it was not an option. Sneezing in the wrong
direction was not recommended... (Remember there was 5KV across the
bulb, and anything could cause it to go off, especially removing the
voltage.) We figured how long it would take for the bleed resistor to
get the voltage down to safe levels (below 2KV), locked the lab,
padlocked the lab, put up a big sign "Do not enter before Tuesday,"
and caught up on paperwork.
This testing resulted in a proposed "lighting system" which would
consist of a motor generator pair, and a triggering circut. Once the
tube fired it would effectively short the generator and bring it to a
stop. The idea was to speed up the production of photolithographic
plates (from exposures measured in minutes to fractions of a second).
Loooking at the issues with the then new OSHA convinced us that the
product could never be marketed. (Note that existing equipment was
just as capable of blinding people if misused, but that this was
"something new.")
--
Robert I. Eachus
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