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Xenon flash tube

Started by bitrex September 7, 2015
Den onsdag den 9. september 2015 kl. 00.31.57 UTC+2 skrev srober...@gmail.com:
> Electronic Goldmine Surplus sells common strobe parts at the right prices... > You might start there. > > You can trigger many ways, a pulse of HV on the external trigger electrode, or series injection triggering, using a transformer in series or a blocking diode to insert a trigger voltage. Even HV DC will trigger it. > > Without the trigger pulse it takes 1000-1700 VDC from Anode to Cathode to break down one of the U shaped tubes. > > This is good reading for the serious technophile: > > http://laser-caltech.web.cern.ch/laser-caltech/report/Flash%20lamp%20Eg&G.pdf > > About 15$ at Autozone gets you the classic car or tractor ignition coil, which works just fine as an external trigger. > > Usually I use an MOC series opto-triac in a six pin package to push charge into the trigger SCR gate lead from a 0.1uf cap via a 100 ohm resistor. > Charging current for the trigger cap comes via a large enough resistor that the SCR is starved below its holding current. I'm using half the Triac as an SCR. > > If I'm not doing that, I use a 555 wired as an inverting driver and push the gate with 100 ohms off pin 3 of the 555. > > If you can find a SGR20N40L or similar IGBT, this app-note lets you "Quench" the strobe by cutting off the current, and the same IGBT triggers the tube that cuts it off. That can be very useful for high speed photography, but I'd start > with normal triggering. > > https://www.fairchildsemi.com/application-notes/AN/AN-9006.pdf > > Steve >
an ignition coil seems like major over kill, heres the innards of a disposble camera: http://www.spudfiles.com/spud_wiki/index.php?title=File:Camera_flash.jpg the trigger transformer is the yellow one -Lasse
On Mon, 7 Sep 2015 20:26:06 -0400, bitrex <bitrex@de.lete.earthlink.net>
wrote:

>On 9/7/2015 8:20 PM, bitrex wrote: >> I got several of these xenon flash tubes down at Rat Shack on sale for >> less than 2 bucks each. >> >> http://www.radioshack.com/long-life-xenon-strobe-tube/2721145.html >> >> Anyone have a design for a junk box circuit that could be used for >> experimenting with these, say firing them from a TTL logic output? > >I guess this works but I don't have anything like that trigger >transformer in stock... > >http://www.bristolwatch.com/ele/
Ebay shows lots of trigger transformers, such as those at http://stores.ebay.com/Xenon-Flash-Tubes/Trigger-coil-/_i.html?_fsub=2679436010 Any of them should work with your flash tubes. Cheers, Dave M
In my defense

In the US, Autozone or their competitors are literally everywhere. They usually stock the small coil. It IS overkill, but the three terminal one is fun for a hobbyist. 

It will also  fire the lamp off a mere AA cell, no need for 100-200V on the primary like a trigger transformer.

Steve 



Den tirsdag den 8. september 2015 kl. 18.53.12 UTC+2 skrev DecadentLinuxUserNumeroUno:
> On Tue, 8 Sep 2015 09:32:14 -0700 (PDT), Lasse Langwadt Christensen > <langwadt@fonz.dk> Gave us: > > >Den tirsdag den 8. september 2015 kl. 18.00.20 UTC+2 skrev John Larkin: > >> On Tue, 8 Sep 2015 08:40:29 -0700 (PDT), George Herold > >> <gherold@teachspin.com> wrote: > >> > >> >On Monday, September 7, 2015 at 8:26:45 PM UTC-4, John Larkin wrote: > >> >> On Mon, 7 Sep 2015 20:20:14 -0400, bitrex > >> >> <bitrex@de.lete.earthlink.net> wrote: > >> >> > >> >> >I got several of these xenon flash tubes down at Rat Shack on sale for > >> >> >less than 2 bucks each. > >> >> > > >> >> >http://www.radioshack.com/long-life-xenon-strobe-tube/2721145.html > >> >> > > >> >> >Anyone have a design for a junk box circuit that could be used for > >> >> >experimenting with these, say firing them from a TTL logic output? > >> >> > >> >> Well, you apply 300 volts across the end leads, with electrolytic caps > >> >> to store as many joules as you think it can stand; that's not > >> >> specified. Wild guess might be 30ish. > >> > > >> >We used to use one in a strobe. > >> >Big yellow cap from Sprague.. 5 uF, 400 V. > >> > >> That's only 0.4 joules, which is OK for a stroboscope but wimpy as a > >> photoflash. A stroboscope is limited by average heating of the > >> flashtube, whereas a photoflash is limited by exploding it in one zap. > >> > >> 300 joules is a pretty big flash, typical for a pro flash with a big > >> spiral flashtube. > > > >here's a 4800J one: https://youtu.be/tfUkDCVqw1I > > > >-Lasse > > Here's another... bigger.... WAY bigger... > > https://www.youtube.com/watch?v=5sPjzWqSb2U
depends on how you count if the flash is shorter than ~160ms it is more than 30kW -Lasse
On Wed, 9 Sep 2015 04:11:00 -0700 (PDT), Lasse Langwadt Christensen
<langwadt@fonz.dk> Gave us:

>Den tirsdag den 8. september 2015 kl. 18.53.12 UTC+2 skrev DecadentLinuxUserNumeroUno:
snip
>> >> Here's another... bigger.... WAY bigger... >> >> https://www.youtube.com/watch?v=5sPjzWqSb2U > >depends on how you count > >if the flash is shorter than ~160ms it is more than 30kW > >-Lasse
Ever seen the quarter shrinker guy's page?
On Tue, 8 Sep 2015 14:51:39 -0700 (PDT), whit3rd <whit3rd@gmail.com>
wrote:

>On Tuesday, September 8, 2015 at 1:33:20 PM UTC-7, amdx wrote: > >> 15 years ago I tried triggering one flashtube with the flash of >> another one. I never got it to work. I didn't try increasing the voltage. > >It needs UV illumination of the cathode. Either UV filtering in the tube(s), >or poor focusing of the illumination onto the target electrode will >defeat the effect. If the 'target' electrode is shaded, behind the reflector >of the flash, that'd explain the difficulty. > >Photothrystors are actually kind of interesting gadgets.
An ordinary NE2 neon bulb can be triggered with low levels of visible light. Failing neon night lights tend to only work in the daytime. The flashtube is quartz, so will admit blue or near-UV light. It should work.
On Wednesday, 9 September 2015 05:30:34 UTC+10, John Larkin  wrote:
> On Tue, 8 Sep 2015 13:33:02 -0500, amdx <nojunk@knology.net> wrote: > > >On 9/7/2015 7:20 PM, bitrex wrote: > >> I got several of these xenon flash tubes down at Rat Shack on sale for > >> less than 2 bucks each. > >> > >> http://www.radioshack.com/long-life-xenon-strobe-tube/2721145.html > >> > >> Anyone have a design for a junk box circuit that could be used for > >> experimenting with these, say firing them from a TTL logic output? > > > > > > Not sure what good it is, but I saw a video where a guy fire of a > >tube with a piezo electric unit from a propane stove. > > Mikek > > That should work. You can also just ramp up the voltage until the tube > fires on its own, at some kilovolts. > > I bet an optical input, like a pulse from a blue or UV LED, could fire > a flashtube too, probably at a pretty high voltage, close to the > natural breakdown.
I sort of did that when I was starting my first xenon arc lamp. By putting the spark gap in a silica tube, I got enough hard UV out of the spark to knock electrons off the electrodes of the xenon arc lamp, and it started every time. The subsequent copies used a commercial spark gap in hard glass tube, and not enough of the hard UV got through to do anything useful to the electrodes of the arc lamp. You had to fire the starter repeatedly until a random electron in the arc lamp gap started the avalanche. Fine for starting a lamp that was supposed to go on and stay on. Not great for flash lamp or the like. My starter was a bit wimpy, and only kept up the 20kV starting voltage for a few microseconds - there was enough stored energy in the starter circuit to sustain the glow-to-arc transition once you got the initial discharge, but you did need that first electron to get everything going. The Southampton Chemistry Department workshop tried a less wimpy starter, but it blew up my 24A at 20V constant current supply that kept the arc running, which was a neat trick. I never did get to see what their scheme had blown up - just heard about it a few years later. -- Bill Sloman, Sydney
On 9 Sep 2015 09:56:58 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

>On 2015-09-08, whit3rd <whit3rd@gmail.com> wrote: >> On Tuesday, September 8, 2015 at 1:33:20 PM UTC-7, amdx wrote: >> >>> 15 years ago I tried triggering one flashtube with the flash of >>> another one. I never got it to work. I didn't try increasing the voltage. >> >> It needs UV illumination of the cathode. Either UV filtering in the tube(s), >> or poor focusing of the illumination onto the target electrode will >> defeat the effect. If the 'target' electrode is shaded, behind the reflector >> of the flash, that'd explain the difficulty. >> >> Photothrystors are actually kind of interesting gadgets. > >Photothyratrons?
Known as lascrs.
"Jasen Betts" <jasen@xnet.co.nz> wrote in message 
news:msovpa$qm1$2@gonzo.alcatraz...
> On 2015-09-08, whit3rd <whit3rd@gmail.com> wrote: >> On Tuesday, September 8, 2015 at 1:33:20 PM UTC-7, amdx wrote: >> >>> 15 years ago I tried triggering one flashtube with the flash of >>> another one. I never got it to work. I didn't try increasing the >>> voltage. >> >> It needs UV illumination of the cathode. Either UV filtering in the >> tube(s), >> or poor focusing of the illumination onto the target electrode will >> defeat the effect. If the 'target' electrode is shaded, behind the >> reflector >> of the flash, that'd explain the difficulty. >> >> Photothrystors are actually kind of interesting gadgets. > > Photothyratrons?
A xenon flash tube is more of an ignitron, really. I don't recall that there's a name for a light-stimulated one, so photoignitron would be descriptive, if nothing else. Tim -- Seven Transistor Labs Electrical Engineering Consultation Website: http://seventransistorlabs.com
On 9/9/2015 11:00 AM, John Larkin wrote:
> On 9 Sep 2015 09:56:58 GMT, Jasen Betts <jasen@xnet.co.nz> wrote: > >> On 2015-09-08, whit3rd <whit3rd@gmail.com> wrote: >>> On Tuesday, September 8, 2015 at 1:33:20 PM UTC-7, amdx wrote: >>> >>>> 15 years ago I tried triggering one flashtube with the flash of >>>> another one. I never got it to work. I didn't try increasing the voltage. >>> >>> It needs UV illumination of the cathode. Either UV filtering in the tube(s), >>> or poor focusing of the illumination onto the target electrode will >>> defeat the effect. If the 'target' electrode is shaded, behind the reflector >>> of the flash, that'd explain the difficulty. >>> >>> Photothrystors are actually kind of interesting gadgets. >> >> Photothyratrons? > > Known as lascrs.
But that is a silicon device. It only becomes gaseous when its limits are exceeded.