steve@alberta.UUCP (Steve Sutphen) (10/17/88)
I am looking for sources for Xenon flash tubes (the kind that are used in camera flashes and strobes). I would like to find data sheets for a flash tube that is in some existing equipment (I cannot see any identification on the part at all) as well as a (cheap) supplier of tubes. I looked in the Efstonscience (the Edmund Scientific distributor for Canada) and could not find such a device. I have two projects that I would like this data for: upgrading the flash level in a friends slide duplicator, and building some experiments to try and freeze moving objects on film. I want to understand what the various parameters are (watt-seconds and duration of the flash) and how to control them (can I just add a larger capacitor to an existing flash to get more light out or would that burn up the tube?). thanks, steve.
cep4478@ritcv.UUCP (Christopher E. Piggott) (10/17/88)
Hi Steve - Here are two sources: (1) RADIO SHACK: Part number 272-1145 - $3.95/ea Trigger: 4Kv, Anode: 200-300v (with a data sheet, but not amazingly helpful) (2) All Electronics 1-(800)-826-5432 P.O. Box 567 Van Nuys, CA 91408 Part Number FLT-1 - 2 for $1.00 Note a few things: (1) Radio Shack will give you quantity discounts of 10% on 12-29Z, 25% on 50-499Z. (I'm not sure what kind of quantity you're looking for, but this offer is good on all electronics parts they sell). (2) The tube from All Electronics is a straight tube, as opposed to radio shack's traditional "U" shaped tube. They did not offer any data in their ad about the tube, but it has just an anode and a cathode (two leads) instead of the usual three. I don't know how to use either of these tubes!!! I posted to sci.electronics last month about how to make use of them with a 12vdc power source, and got *NO RESPONSES*. If you can help me, get in touch by mail (preferrably bitnet, as it's more reliable). Thanks, and good luck, Steve. /Christopher E. Piggott cep4478@RITVAX.BITNET ..decvax!ucbvax!ucbcad!ames!rochester!ritcv!cep4478 (or whatever else works through rochester!ritcv)
henry@utzoo.uucp (Henry Spencer) (10/21/88)
In article <144@snaring.UUCP> steve@alberta.UUCP (Steve Sutphen) writes: >I am looking for sources for Xenon flash tubes (the kind that are used in >camera flashes and strobes)... Radio Shack sells a couple of kinds of them, although without much in the way of documentation (they're basically meant as replacements for flashtubes in RS gadgets). -- The meek can have the Earth; | Henry Spencer at U of Toronto Zoology the rest of us have other plans.|uunet!attcan!utzoo!henry henry@zoo.toronto.edu
jbm@eos.UUCP (Jeffrey Mulligan) (10/21/88)
From article <944@ritcv.UUCP>, by cep4478@ritcv.UUCP (Christopher E. Piggott): > (1) RADIO SHACK: > Part number 272-1145 - $3.95/ea > Trigger: 4Kv, Anode: 200-300v > (with a data sheet, but not amazingly helpful) > I don't know how to use either of these tubes!!! I posted to > sci.electronics last month about how to make use of them with a 12vdc power > source, and got *NO RESPONSES*. If you can help me, get in touch by mail > (preferrably bitnet, as it's more reliable). Thanks, and good luck, Steve. In my college days I did a lot of playing around with the R.S. tubes. I was using a power supply of around 160V dc (This was just the 115V ac run through an isolation transformer and rectified). The flash capacitor was a big thing, a couple of microfarads rated for 400V. A prof. put me onto a cute trick to get them to recharge to double the supply voltage: they recharged through a series diode/inductor. The inductor kept the recharging current low until the gas had de-ionized, while the diode kept the flash capacitor from discharging back onto the supply capacitors. The charging curve looked like a half cycle of a sine wave. Radio Shack also sells the little trigger transformer for these guys. I used an SCR to discharge a small capacitor through the primary to get the kV needed to ionize the xenon. My memory is a little hazy here, but I think I needed a transistor to inject enough current to trigger the SCR from ttl control signals. I also used opto-isolators between the high voltage stuff and the logic circuitry. Things were great until I started trying to get the things to strobe at 1kHz (don't ask why). I ended up making my own inductors to get the right L value for a 1 ms recharging time. Unfortunately, the inductors I made (magnet wire wound onto a half inch steel rod) had too much resistance (a few hundred ohms), resulting in a non-neglible charging current at the end of the flash. What happened was that these babies would strobe at 1kHz for a few seconds at which point they turned into arc lamps- i.e. the gas just stayed ionized and shorted out the power supply. At this point they were HOT! The moral was I wasted a lot of effort designing a fancy system around a $3 flash tube for which I had no data sheets and couldn't perform in the way I wanted it to. I have a nice catalog from EG&G describing their line of flashtubes, they do give specs, but of course their stuff is expensive. Impressive stuff, though, like the 4 ft. water cooled flashtube used for aerial phtography... -- Jeff Mulligan (jbm@aurora.arc.nasa.gov) NASA/Ames Research Ctr., Mail Stop 239-3, Moffet Field CA, 94035 (415) 694-6290