Reply by DecadentLinuxUserNumeroUno September 11, 20152015-09-11
On Thu, 10 Sep 2015 20:56:30 -0500, John S <Sophi.2@invalid.org> Gave
us:

>But that is a silicon device. It only becomes gaseous when its limits >are exceeded.
Must have been what happened to you and accounts for the stench which pervades whenever you make a post.
Reply by John Larkin September 11, 20152015-09-11
On Thu, 10 Sep 2015 15:35:45 -0500, "Tim Williams"
<tmoranwms@charter.net> wrote:

> >"Jasen Betts" <jasen@xnet.co.nz> wrote in message >news:msovpa$qm1$2@gonzo.alcatraz... >> On 2015-09-08, whit3rd <whit3rd@gmail.com> wrote: >>> On Tuesday, September 8, 2015 at 1:33:20 PM UTC-7, amdx wrote: >>> >>>> 15 years ago I tried triggering one flashtube with the flash of >>>> another one. I never got it to work. I didn't try increasing the >>>> voltage. >>> >>> It needs UV illumination of the cathode. Either UV filtering in the >>> tube(s), >>> or poor focusing of the illumination onto the target electrode will >>> defeat the effect. If the 'target' electrode is shaded, behind the >>> reflector >>> of the flash, that'd explain the difficulty. >>> >>> Photothrystors are actually kind of interesting gadgets. >> >> Photothyratrons? > >A xenon flash tube is more of an ignitron, really. I don't recall that >there's a name for a light-stimulated one, so photoignitron would be >descriptive, if nothing else. > >Tim
Big Marx generators often have their spark gaps fired by lasers.
Reply by John S September 10, 20152015-09-10
On 9/9/2015 11:00 AM, John Larkin wrote:
> On 9 Sep 2015 09:56:58 GMT, Jasen Betts <jasen@xnet.co.nz> wrote: > >> On 2015-09-08, whit3rd <whit3rd@gmail.com> wrote: >>> On Tuesday, September 8, 2015 at 1:33:20 PM UTC-7, amdx wrote: >>> >>>> 15 years ago I tried triggering one flashtube with the flash of >>>> another one. I never got it to work. I didn't try increasing the voltage. >>> >>> It needs UV illumination of the cathode. Either UV filtering in the tube(s), >>> or poor focusing of the illumination onto the target electrode will >>> defeat the effect. If the 'target' electrode is shaded, behind the reflector >>> of the flash, that'd explain the difficulty. >>> >>> Photothrystors are actually kind of interesting gadgets. >> >> Photothyratrons? > > Known as lascrs.
But that is a silicon device. It only becomes gaseous when its limits are exceeded.
Reply by Tim Williams September 10, 20152015-09-10
"Jasen Betts" <jasen@xnet.co.nz> wrote in message 
news:msovpa$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
Reply by John Larkin September 9, 20152015-09-09
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.
Reply by Bill Sloman September 9, 20152015-09-09
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
Reply by John Larkin September 9, 20152015-09-09
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.
Reply by DecadentLinuxUserNumeroUno September 9, 20152015-09-09
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?
Reply by Lasse Langwadt Christensen September 9, 20152015-09-09
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
Reply by September 8, 20152015-09-08
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