Many small flashtube manufacturer ratings below are for Excelitas, formerly Perkin Elmer, formerly EG&G Heimann Division flashtubes that match the descriptions of ones I have tested. In the event the flashtube was made by someone else, ratings may differ slightly and may differ substantially for maximum flash energy. Although I mention some conditions under which I believe some flashtubes will operate safely outside their manufacturer's ratings, do so only at your own risk.

For more info on where to get these, go to my source/supplier page.

For some more info on large items, go to my Big Strobe Page.

Please note that "joule" and "watt-second" (W-S) mean the same thing.

Ko figures are for doing shaped pulse tricks and/or using series inductors. All of the small and medium flashtubes and a majority of the large / high power flashtubes below will work with the recommended voltages, energy levels, etc. without inductors. Inductors are only required where full power / energy usage of a minority of the large / high power flashtubes mentioned below, and alternative ratings for use without inductors are given for some of these.

- Tiny cheap camera tube with 13 mm. arc length / BGA 0013
- Cheap to semi-cheap photoflash tube with 30 mm. arc length 3.15 mm diameter
- Cheap to semi-cheap photoflash tube with 30 mm. arc length 4mm diameter
- Cheap to semi-cheap photoflash tube with 35 mm. arc length
- Cheap to semi-cheap photoflash tube with 30 mm. arc length 4mm diameter
- Cheap photo tube 3.5 mm. diameter 36 mm long 18.5-20 mm. arc length
- Popular U-shaped flashtube 30*16 mm. with 6 mm tubing

- U-tube 50*24 mm 8 mm tubing U-8538
- FT-118, 1-1/2 turn tube 45 mm tall 26 mm wide 6 mm tubing
- FT-218, 1-1/2 turn tube 55 mm tall 33 mm wide 8 mm tubing
- SG 305

- Speedotron MW8QV / 14570
- Photogenic C4-5 and C4-15
- EG 9902-1
- JG 7905 / JG7905
- PAR56 Airport Strobe GN34 / GN-34 / NSN 6240-01-006-1260
- INP3/7-80 / INP3-7/80A / IFP-800
- FX-103C-3 / FXQ-1302-3
- XOP-750 and XOP-1500

Heimann's ratings are minimum voltage of 270 volts, nominal voltage of 300 volts, maximum voltage of 350 volts, maximum energy of 8 watt-seconds, and maximum power of 1.6 watts. Life expectancy at 8 joules and 300 volts is 2,000 flashes. Lowering the flash energy to 2 joules should get a disproportionately longer life.

I have ruined one of these tubes within an hour or two with an average power of 3.5 watts and favorable energy and voltage.

Electrolytic capacitors should generally be well over 50 uF and up to 220 uF. Smaller electrolytic capacitors will have excessive internal resistance which will reduce efficiency, but this is not bad with a parralel bank of at least three preferably at least four Kemet ESG226M400AM5AA 22 uF capacitors or other capacitors selected for low ESR. More compact aluminum electrolytics tend to have higher ESR. Also, larger capacitance of aluminum electrolytics favors less ESR (effective series resistance). You also probably don't want to exceed .06 maybe .066 coulomb of charge or else electrode wear may be excessive. Nonelectrolytic capacitors can be efficient at lower values, but below about 47-68 uF or so (updated from 47 uF 10/23/2023), the spectrum will be less like that of dayligh and specific spectral lines will become prominent. I show the line spectrum (with less continuous spectrum than actually occurs) in http://donklipstein.com/don/spectra.html.

This flashlamp typically produces light with color temperature significantly higher than 5500 K, which makes it more blue than optimum for color slide film photographs, especially when the energy storage capacitor's ESR is low (less than .3 ohm). Many camera flashes with this flashtube have filters or diffusing lenses that have a yellowish or yellowish orangish tint. The bluish color can be mitigated by using an unusually low voltage such as 200 volts. This requires greater capacitance to get the same amount of flash energy, which typically means less capacitor ESR. This also decreases capacitor losses by increasing the flashtube's arc resistance, although that is still mostly around 1 ohm. With 200 volts a 330 microfarad capacitor has .066 coulomb of charge and 6.6 watt-seconds. Although maximum usable energy is decreased by lower voltage, and the lower voltage and resulting lower color temperature both slightly decrease this flashtube's efficiency, this is mitigated by lack of need for color filtering and decrease of percentage of flash energy being lost in the energy storage capacitor. However, low ESR is still good for better efficiency. Flash duration will be increased, but by most measures be no more than a few milliseconds.

One 330uF capacitor that appears suitable for this, despite voltage rating much higher than needed, is EPCOS / TDK B43545C9337M000. Its ESR is .06 to .18 ohm depending on test conditions.

Lower voltages well below 270 volts may necessitate the trigger circuit to have higher peak voltage and faster risetime in order to achieve reliable triggering, especially if the flashtube has been through a lot of use.

I tested efficiency at various energies at 280 volts. The efficiency is half that at 8 joules at .5 joule, and 80 percent of the 8-joule level at 1.7 joules, and 90 percent of the 8-joule level at 2.8 joules. Better low-energy efficiency may be obtained at higher voltages, preferably with non-electrolytic capacitors.

Estimated xenon pressure 450 Torr, estimated Ko 9.5 ohms-amps^.5 for the Heimann version. Others will be similar enough - estimated pressure 500 Torr and Ko maybe 10 possibly as much as 11 ohms-amps^.5 for tubes I saw in Fuji cameras.

EG&G's ratings are minimum voltage of 250 volts, nominal voltage of 330 volts, maximum voltage of 360 volts, maximum energy of 28 watt-seconds, and maximum average power of 1.87 watts. Life expectancy at 28 joules and 330 volts is 1,000 flashes. I suspect that some equivalents may have a maximum reliably safe energy anywhere from 15 to 35 watt-seconds or joules. I also expect the maximum safe average power to be 2.5 watts if ventillation is good, the voltage is 300 to 360 volts, and the energy is 6 to 15 joules.

I believe this tube can handle 3 to probably 3.2 watts average input power with moderate flash energy of a few to around 10 W-S.

I have not done much testing, but expect that approx. 3/4 joule of energy is required to get half this tube's ultimate efficiency (1 joule for the Electronic Goldmine one below) and roughly 100 uF of capacitance is necessary to get a daylight-like spectrum without significantly prominent xenon ion spectrum lines.

Electronic Goldmine's A1033 flashtube/reflector combination has a flashtube very similar to the BGA-3030, but about 3.5 mm. in diameter, which they claim can handle 50 joules. I believe it can handle 4 watts average power with favorable flash energy of a few joules, but life expectancy in strobe duty may be disappointing.

Please note that EG&G Heimann Division also makes a tube of the same shape and outside diameter, but with a slightly wider inside diameter of 2.1 mm and a slightly shorter length (not including leads) of 42 mm. The EG&G tube matching this description is the CGA4230. EG&G's ratings for this one are minimum voltage of 220 volts, nominal voltage of 380 volts, maximum voltage of 400 volts, maximum energy of 36 watt-seconds, and maximum average power of 3.6 watts. Its life expectancy at 36 joules and 380 volts is 1,000 flashes. I suspect the lower-rating BGA3030 and any equivalents thereof are more common than the CGA4230 and any equivalents it has.

This tube is 44-45 mm long (or very slightly shorter) not including leads, 4 mm outside diameter, and 2.4 mm in inside diameter. This is or matches the description of the Excelitas (formerly EG&G Heimann Division) BGGP 6330 / BGGP 6330 (N)(H). Excelitas has discontinued manufacture of this flashtube, but limited stock remains at Digi-Key as of 10/12/2023.

Excelitas ratings are minimum voltage of 300 volts, nominal voltage of 325 volts, maximum voltage of 350 volts, maximum energy of 49 watt-seconds, and maximum average power of (my interpretation from the datasheet) 8.4 watts, probably short term. Life expectancy is not specified by the datasheet. I believe this flashtube can handle 4.5 to probably 6 watts average input power with moderate flash energy of a few to around 12 W-S. It is made of "hard glass" which is tougher than the cheaper grade of borosilicate glass that many flashtubes are made of.

The datasheet says typical capacitance is 800 uF. I think this flashtube will work efficiently and produce a reasonably daylight-like spectrum good for photoflash use with capacitance at least as low as 220 uF, maybe 88 microfarads. I expect good efficiency with capacitance at least as low as 110 uF if the capacitor's ESR is .22 ohm or less, which may require paralleling multiple capacitors to achieve ESR this low with multiple lower capacitance capacitors if the capacitor type is electrolytic.

A 330 uF capacitor that I recommend is EPCOS / TDK B43545C9337M000. Two of these in parallel will achieve great performance.

Estimated xenon pressure 500 Torr, estimated Ko 16.3 ohms-amps^.5. Estimated minimum capacitance to efficiently produce a daylight-like spectrum is 47-56 uF. Estimated minimum energy to achieve half this flashtube's ultimate efficiency is 2.5 joules.

I expect voltage at least as high as 400 volts with flash energy up to at least 10 joules is OK because of the high xenon pressure, although exceeding 330-350 volts may result in color being excessively bluish for color photographs.

Maximum flash energy is 60 W-S according to both Heimann and Mouser.

Minimum voltage is 210 volts and maximum voltage is 350 volts and nominal voltage is 330 volts according to Heimann. Nominal voltage is 360 volts according to Mouser. The lower max. voltage published by Heimann is probably conservative and it should be safe to exceed that 350 volt figure by a little.

Life expectancy according to both Heimann and Mouser is 3000 flashes, probably at 330-360 volts and 60 watt-seconds. Maximum average power input according to Heimann is 6 watts, but life expectancy in repeated strobe use may be disappointing especially with higher flash energy.

I do not know the minimum energy to get half the ultimate efficiency but it is probably in the ballpark of 1 joule. I do not know the minimum capacitance to get a good daylight-like spectrum but this is probably around 100 to maybe as much as 220 microfarads.

Heimann's specifications: Anode voltage 200 volts minimum, 330 nominal, 350 maximum. Maximum energy 22 W-S, although Electronic Goldmine only claims 10 for theirs. Max. average power input 2.2 watts. I think it can withstand 3 watts with flash energy at a favorable level of a few W-S. Heimann's life rating is 3000 flashes at 22 joules, 330 volts, and 2.2 watts.

I have yet to do much testing, but I believe the energy required to get half the ultimate efficiency is around .9 W-S. I believe the minimum capacitance to get a daylight-like spectrum without much bright line content is around 100 uF.

All of these are similar enough to be interchangeable, at least in most equipment that has these flashtubes.

Excelitas' ratings are minimum voltage of 200 or 220 volts, nominal voltage of 500 volts, maximum voltage of 550 volts, maximum flash energy of 6 watt-seconds, and maximum average power of 6 watts. Life expectancy at 6 joules and 500 volts is 5 million flashes. UPDATE 10/12/2023: Excelitas has discontinued manufacturing the BUB 0641 .

Amglo's ratings are minimum voltage of 250 volts, typical voltage of 350 volts, maximum voltage of 400 volts, maximum flash energy of 6 joules and maximum average power input of 6 watts.

Ratings by the Verre & Quartz company are minimum voltage 160V, typical voltage 300V, maximum voltage 400V, maximum energy 10 joules, maximum power 5 watts.

Radio Shack's ratings vary. The maximum voltage according to the worst rating I ever heard from Radio Shack is 300 volts. For high energy flashing, I recommend voltages around 280 to 330 volts. I have heard all sorts of maximum energy ratings for these tubes, but I once cracked one with about 30 joules at a favorable voltage. I would say the maximum reliably safe energy is 15 joules at 300 to 330 volts. I would derate this in proportion to voltage below 300 volts (.05 joule per volt). I would derate this linearly from 15 joules at 330 volts to 6 joules at 450 volts (.075 joules per volt). This tube will survive 15 joules at lower voltages down to 200 volts and 20 joules around 280-300 volts, but end discoloration will occur more quickly.

I tested efficiency at various energies at 280 volts. The efficiency is half that of the 15-joule level at 1.5 joules, and 80 percent of the 15-joule level at 5.5 joules, and 90 percent of the 15-joule level at 8 joules. Better low-energy efficiency will probably be obtained at higher voltages with especially conductive capacitors such as axial lead foil types and maybe some motor run types and some axial lead electrolytics, or (best) parallel banks of small motor run capacitors or capacitors made for pulse use.

This flashtube is made mainly for strobelight and warning beacon use. It works well at moderate energy levels of a few joules and highish voltages in the 400 to 550 volt range. Its spectrum under these conditions is low on deep red and color film photographs taken under these conditions will probably have a green-blue tint.

This flashtube requires around 680 to maybe around 1,000 uF to efficiently produce a daylight-like spectrum without significant ion spectrum lines. To safely handle this and to avoid a bluish color, the voltage would be on the low side - maybe 200-250 volts. Efficiency is probably reduced below 240-250 volts. This flashtube is not the first choice for color photography.

At energy levels and voltages favorable to high efficiency, this flashtube will probably safely handle an average power of 8 watts if ventillation is reasonably good. At unfavorable voltages and energy levels, the maximum safe average power can be as low as 5 watts or maybe a little less.

Approx. arc length 45 mm, tubing bore 4-4.5 mm, estimated xenon pressure 70-80 Torr maybe sometimes 100 - and these figures vary a little from one brand to another. Estimated Ko typically 11 ohms-amps^.5.

BUB 0641 datasheet at Excelitas, via the Wayback Machine.

The Verre & Quartz VQX S 20 W is similar, except for its height not including its leads or "tip" being 47 mm instead of 50.

Nominal/typical anode voltage 400 volts according to Mouser, 450 volts according
to Verre & Quartz, should work from 300 to 450 volts, and to 800 volts at lower
energy of 10 joules or less.

Maximum flash energy 100 joules according to Mouser, 50 joules according to
Verre & Quartz. I would derate this proportionately with voltage below 400
volts. Energy handling probably also decreases for higher voltages. I estimate
maximum average power to be 12 watts, 15 with favorable voltage (400-600 volts)
and favorable flash energy of at least 10 joules. Verre & Quartz says 20 watts,
which I consider optimistic and requiring favorable energy around 20-40 joules
and favorable voltage around 400-450 volts and favorable ventillation.

I estimate the efficiency to be half of ultimate efficiency at 4 joules.

This tube has lowish xenon pressure that I estimate to be 70 Torr (maybe 75-80 as of 10/20/2023), and I estimate roughly 680 - 1000 uF (updated from 470-1000 uF 10/12/2023) of capacitance would be needed to get a daylight-like spectrum. This tube is probably intended mainly as a strobe tube.

Approx. arc length 80 mm, tubing bore 6 mm, estimated Ko 12 ohms-amps^.5.

Nominal anode voltage 450 volts, should work from 400 to 800 volts.

Maximum flash energy 125 joules according to Mouser. I would derate this proportionately with voltage below 450 volts. Energy handling should be good to much higher voltages, probably at least 700 and maybe 800 volts.

I estimate average power handling to be 15 watts, and this prefers higher voltages.

Estimated capacitance needed to get a daylight-like spectrum 220 uF. My recommended voltages for use for photoflash (daylight-like spectrum) 450-550 volts.

Estimated energy required to get half the ultimate efficiency 4 joules.

Approx. arc length 125 mm, tubing bore 4 mm, estimated Ko 28 ohms-amps^.5.

Nominal anode voltage 450 volts, should work from 400 to 550 volts. Higher voltages to 800 volts should be OK at moderate flash energy up to 20 joules.

Maximum flash energy 250 joules according to Mouser. I would derate this proportionately with voltage below 450 volts. Energy handling may decrease above 450 volts.

I estimate average power handling to be 25 watts.

This tube has a very low xenon pressure that I estimate to be about 40 Torr. I estimate the capacitance needed to get a daylight-like spectrum to be around 680-1000 uF. This tube is probably intended more as a strobe tube than as a photoflash tube. The low xenon pressure will probably reduce the efficiency a little, especially in production of a daylight-like continuous spectrum good for color slide film photography. Expect the color to be a bit more bluish or green-bluish than usual.

Estimated energy required to get half the ultimate efficiency: 4 joules.

Approx. arc length 160 mm, tubing bore 6 mm, estimated Ko 21 ohms-amps^.5.

These are available from Digi-Key as a "marketplace product". This means that this item can be ordered from Digi-Key, but it will be supplied by a different company that has its own warehouse and shipping charges.

The SG 305, AKA SG305 and as SG 305(SZ)(H) is a quartz linear strobe flashlamp. Its overall length is 69 mm not including leads, 103 mm including leads. Its arc length is 40-41 mm. Its outside diameter is 8 mm, and its inside diameter (bore) is 6 mm. Estimated xenon pressure 350-400 Torr, estimated Ko 8.5 .

Heimann / Excelitas ratings are: Maximum average power of 25 watts, maximum flash energy of 5 joules, anode voltage minimum 400 volts, nominal 550 volts, maximum 600 volts. They mention nominal energy storage capacitance of 4 uF, which means about .6 joule at 550 volts, which can supposedly be withstood at a flash rate of 41 flashes per second. They mention flash rate of 5 to 300 Hz or flashes per second. 25 watts at 300 flashes per second means flash energy of .083 joule, which I recommend as minimum flash energy with voltage of 550-600 volts. A datasheet is available here.

I figure average power of 30 watts is tolerated with higher energy around 5-10 joules and favorable voltage for higher flash energy around 400-500 volts. Also, I suspect this flashtube may overheat without fan cooling in a small closed container with lower flash energy around or less than 1 joule and with average power input above 20 watts.

I expect flash energy greater than 5 joules, likely at least as great as 20 joules, to work well at lower voltage around 400 volts, although with less average power to avoid electrode overheating. The manufacturer states life expectancy of 250 hours at 25 watts, but I expect at least a few thousand hours with average power of 15 watts and favorable flash energies of 2-5 joules and favorable voltages around 450-500 volts at ~5 joules and 500-550 volts around ~2 joules, probably also with around 1 joule and voltage around 550 volts.

Estimated minimum capacitance to get a daylight-like spectrum is ~ 330 uF. I figure this flashtube works best for color film photography at low voltage around 350 volts which may require an aggressive triggering circuit.

For using a series inductor for a .5 millisecond 25 watt-second flash, I figure 470-480 uF, 330-350 volts, and inductance of about 47 microhenries. With assumption here of arc radiation efficiency of 60% for 15 joules which means 30 kilowatts, this means about 4 kW per cm^2 of radiation from the arc surface. I figure a blackbody has surface temperature about 5150 K to radiate this, so I expect this xenon flashtube to do this with color temp. about 5500 K.

This flashlamp is made of quartz that is doped to block ozone forming UV, but is expected to produce longer wavelengths of UVC shortwave UV and UVB.

The tube is a 2-turn coil (vertical axis) in a glass "dome" (dome-tipped tube) that has holes in it to allow for cooling. This whole assembly is on a ring-shaped base with three pins slightly wider than banana plugs.

This is a quartz tube with massive ratings: Maximum energy of 3200 joules and maximum power of several hundred watts with forced air cooling (at least a kilowatt short term) and probably a couple hundred watts without forced air cooling. I have given it 700-800 watts average power without forced air cooling long enough to make the tubing glow red-hot, even orangish (800 degrees C?) and it survived, although I do not recommend such abuse.

Recommended voltage is 700 volts to at least a kilovolt. I would derate
energy and power proportionately with voltage below 900 volts. I think
this tube has better efficiency at higher voltages of at least 900 volts.

In my experience with one of these that I got in 1996, this tube sometimes
self-fires at voltages as low as 1600 volts. I would not design equipment to use
nearly this much voltage for the main energy storage capacitor for this tube.

For impressive life expectancy I would avoid using energy over 1000 joules.

**UPDATE 5/15/2020:** The tubing diameter is not always the same and is
sometimes (maybe usually) wider than stated here before.

Estimated energy requirement to get half the ultimate efficiency is 15-27
joules (updated from 15-20 joules).

This tube triggers easily and does not need more than 4 kilovolts to trigger in my experience with one of these that I got in 1996.

Approx. arc length 220 mm, tubing bore 6-7 mm (updated from 6 mm), estimated xenon pressure 80 maybe 100 Torr as of 1996, estimated Ko 24-28 ohms-amps^.5.

Estimated minimum capacitance for daylight-like largely continuous spectrum is 300-400 microfarads (updated from 300 microfarads).

This is a quartz tube and has high energy and power ratings.

This is a ring-shaped tube on a ring-shaped base and having a glass
tubular "dome" over the tube with a hole in the dome tip for ventillation.

Maximum energy is at least a kilojoule but I prefer to not exceed 500 joules in
order to get impressive life expectancy. It is used in the Powerlight 1500SL
light unit. That light unit easily delivers 150 watts of average power but the
tube may prefer somewhat less long-term unless forced air cooling is used.

Recommended voltage 400-525 volts for photoflash duty, but much more (at
least 800 volts) is OK in strobe use with lower energy of 50 joules or
less. I would derate energy and power handling proportionately with
voltage below 500 volts.

Estimated energy required to get half the ultimate efficiency is 20-25
joules, although more (at least 60 maybe 100 joules) seems needed to make
the arc expand enough to solidly and evenly fill the flashtube.

This tube has a higher requirement for trigger voltage than many other tubes - I would recommend at least 6 kilovolts for reliable triggering.

Approx. arc length 110 mm, tubing bore 10 mm, xenon pressure estimated 80 maybe 100 Torr, estimated Ko 11 ohms-amps^.5.

Estimated minimum capacitance for daylight-like mainly-continuous spectrum is 1500 microfarads.

The EG 9902-1 AKA EG 9902-1(SZ)(H) is a large strobe lamp with overall length of 392 mm, arc length of 312 mm, tubing outside diameter of 10 mm, and inside diameter of 8 mm. Estimated xenon pressure is 50 maybe 60 torr. Estimated Ko is 32.2 ohms-amps^.5. Estimated energy requirement to achieve half of this lamp's ultimate efficiency is 45-58 joules. Estimated minimum capacitance to get a good daylight-like continuous spectrum is 667 microfarads.

The manufacturer's ratings are anode voltage minimum 480 volts, nominal 550 volts, maximum 700 volts. I consider these voltages unusually low for this flashlamp's arc length. I expect this flashlamp will work well and safely with much higher voltage up to 1350 volts, and up to 2500 volts with flash energy up to 60 joules. I recommend at least 2000 volts for good efficiency by producing the ion spectrum when flash energy is 60 jouless or less. Voltage higher than 1100 volts may result in color that makes color slide photos bluish. The color may not be excessively bluish for color slide photos with voltage a little higher than 1100 volts if the flash energy is much less than 250 joules.

This flashlamp is rated for high average power handling of 1500 watts. Its ratings include flash rate of 2-14 flashes per second, which means flash energy of 107 to 750 joules. I expect 1500 watts is only reliably repeatedly survivable for several seconds. For good life expectancy of several thousand hours of continuous strobe use without large loss of light output, I recommend:

Average current not exceeding .18 amp.

Charge per flash not exceeding .7 coulomb.

Voltage at least 870 volts for good efficiency, maximum 1350 volts without a
series inductor. Higher voltage can be tolerated with lower flash energy
less than 250 joules.

Average input power without a series inductor not exceeding 200 watts with
flash energy at least 250 joules, and derated with lower flash energy at a rate
of .3 watt per joule, which means 125 watts at very low flash energy. Average
input power with a series inductor should not exceed 225 watts with flash
energy at least 250 joules, and be derated with lower flash energy at a rate of
.4 watt per joule, which means 125 watts at very low flash energy.

This flashlamp is made with a grade of quartz that is doped to block ozone-forming wavelengths of ultraviolet. This flashlamp is likely to produce hazardous UV in longer wavelengths of the UVC range and in the UVB range.

Data for the EG 9902-1 flashlamp is available here.

This lamp has substantial similarity to the XOP1500 and appears likely to work in equipment that is untended to use the XOP1500. Because of this, I mention this lamp in my my xop1500 file.

This is a long large flashtube mostly used in photocopiers. Its ratings by Excelitas are for using it gently so that it would have life expectancy of 15 million flashes. Its main ratings are for flash energy of 200 joules with voltage of 1500 volts minimum, 2100 volts nomimal, 2200 volts maximum, with 1 flash per 1.1 seconds at the maximum recommended flash energy, which means maximum average input power of 180 watts.

Update 7/8/2018: I remember from a copy of an EG&G Heimann catalog that I received in 1996 that 200 joule flashes can be repeated at a rate up to 1.3 Hz, for average input power of 260 watts, with life expectancy of 10 million flashes. I suspect this 260 watts depends on good ventillation or mild forced air cooling, and/or needs to be derated proportionately with the main energy storage capacitor voltage if that is less than 2100 volts. I also suspect that this flashtube has greater temperature rise as flash energy decreases below 200 joules. (If average power input is unchanged and flash frequency increases - update 1/7/2019.) However, I expect the efficiency loss (and increased tube heating) from lower flash energy to be mitigated from use of higher voltage (more than 2100 volts) at the main energy storage capacitor.

I think this flashlamp is good for somewhat higher voltages, to at least 2500 volts without resorting to series inductor tricks with flash energy of 500 joules or less, up to 3000 volts with 100 joules or less.

As for flash energy, I think this flashlamp is good for flash energy up to 500 maybe 1000 joules, especially with voltage of 2100-2500 volts, depending on desired life expectancy. Its electrodes are small in comparison to the length and diameter of this flashtube, because this flashtube was designed for unusually low flash energy, flash charge in coulombs, and low average power and low average current, in comparison to other quartz flashlamps.

The current company that owns what used to be EG&G Heimann is Excelitas, and they publish some ratings for the JG 7905 flashlamp at http://www.excelitas.com/Lists/Flashlamps/DispForm.aspx?ID=47 via the Wayback Machine. (Link updated 10/27/2023)

I consider the 1500 volt minimum as excessively low, and I recommend at least 1600 preferably at least 1700 volts for reliable flashing.

I consider it OK to use up to 6% maybe 10% more voltage than I recommend in my guidelines for most photoflash and some strobe use, even higher voltage when the flash energy is 100 joules or less.

Flashtube tubing inside diameter is 8 mm, arc length is about 490 mm. Estimated xenon pressure is 140 - 200 Torr. Estimated minimum capacitance for a daylight-like spectrum is 100-140 microfarads, when the voltage is high enough to favor the xenon ion spectrum if capacitance is small. Estimated energy needed to get half the efficiency achieved with 1,000 joules is 100-130 joules. My estimate of this flashlamp's Ko is 62-67 ohms-amps^.5.

Usage with 2,000 volts and 54-60 joules requires a series inductor. UPDATE 5/15/2000 About 40 microhenries, 39 microhenries should work.

Without a series inductor: I recommend much lower voltage of 1200 volts with flash energy of 60 to (aggressively) 300 watt-seconds (updated from 60-400 5/15/2020), 1250 volts is OK with lower flash energy about or less than 60 watt-seconds. Voltage a little above 1250 volts is OK with flash energy about or less than 35 watt-seconds, 2000 volts is OK without a series inductor with 8 watt-seconds (4 watt-seconds for airport grade reliability for multiple millions of flashes).

UPDATE 5/15/2020 For color photography use without a series inductor, I recommend even lower voltage of 800-1,000 volts, preferably about 800 volts to avoid an excessively bluish color. I recommend 250 watt-seconds at 1000 volts if long life of at least a few thousand maybe 10,000-25,000 flashes is desired, and I would derate this proportionately with voltage for lower voltages. Note that this flashlamp is a sealed beam spotlight lamp.

I recommend that maximum average power be derated linearly with voltage from 120 watts, as voltage is decreased from 2000 volts. This means 72 watts at 1200 volts. Maximum average power handling is less if the flash frequency is more than 2 flashes per second. Estimated amount of energy required to achieve half the efficiency achieved with a few hundred joules is 22-25 joules.

Rated life expectancy is 4 million flashes at 60 joules and 2000 volts, and I expect the same if flash energy and voltage are decreased by equal percentages (such as with 36 joules and 1200 volts). I expect somewhat reasonable life expectancy (at least a few thousand maybe 10,000-25,000 flashes UPDATE 5/15/2020) with up to 300 joules at 1200 volts (no inductor necessary), or 500 joules at 2,000 volts (with a 390 microhenry inductor, or a little less inductance if extreme care is taken to minimize resistance).

Estimated capacitance required to efficiently achieve a daylight-like continuous spectrum: 38 microfarads.

UPDATE 12/11/2018: This lamp is used with an "individual control cabinet" that has three capacitors totaling 27 microfarads (1.25, 2.75 and 23 microfarads), relays for selecting capacitors for three different flash intensities, a power supply for charging these capacitors to 2,000 volts DC, and an inductor that is used when the 23 microfarad capacitor is used with the other capacitors. This flashlamp can be used safely with up to 4 microfarads charged to 2,000 volts without an inductor.

These are quartz linear flashlamps that are designed for water cooling. The INP3-7/80A has a coating, apparently a dichroic one, that blocks UV. The IFP-800 does not have the coating that the INP3-7/80A has. The IFP-800 produces at least some ozone-forming UV.

I have not yet identified the seal technology, so I cannot yet rule out a need to keep the temperature of the seals well below 150 degrees C. These flashlamps are on eBay at very low prices. These lamps are also available from sources other than eBay.

I have seen what appears as two different xenon pressure versions of both of these flashlamps, with discernably different discharge characteristics when tested on a neon sign transformer.

UPDATE 9/23 2019 - I plan to post a photo that shows various markings on these lamps that *may* correlate with the xenon pressure (not yet done 10/5/2023).

Arc length is about 80 mm, tubing bore is estimated as 7.2 mm. As of 7/7/2018, my preliminary estimates of xenon pressure are 450-480 Torr for the higher pressure version and 200 Torr for the lower pressure version. My preliminary estimate of Ko is 14.2 ohms-amps^.5 for the higher pressure version and 12.1 ohm-amp^.5 for the lower pressure version. If you don't know which version you have, I recommend designing for 13.5 ohms-amps^.5.

UPDATE late evening 7/9/2018

This is a slightly overexposed, slightly color-corrected photo of two of these lamps in series, being powered by a neon sign transformer. The arc dances around more in the higher pressure version, less in the lower pressure version.

NOTE - the arc dances around less when only one flashlamp is powered by a neon sign transformer, as opposed to two or more lamps in series. When one lamp of the low pressure version and no others is powered by a neon sign transformer, its arc may stand still and straight.

The arc has a color that is slightly purplish white or "slightly purplish grayish white" in the high pressure version, noticeably more bluish and somewhat dimmer in the low pressure version. CAUTION - the arc color may appear more bluish than shown here in rooms where persons have their vision "white balanced" on warmer color lighting with color temperature of 3500 K or less.

Estimated minimum capacitance for a daylight-like spectrum is 180 microfarads (updated 12/10/2018) for the higher pressure version, 450 microfarads for the lower pressure version. Estimated energy required to achieve half the ultimate efficiency is 45 joules for the higher pressure version, 20 joules for the lower pressure version.

I publish guidelines here for quartz linear laser pump flashlamps.

My recommendations for usage of the low pressure version without a series inductor for photography: Main voltage 360-480 volts, maximum charge 1.61 coulombs, maximum energy 385 joules. The datasheet specifies 580 volts typical, 610 volts maximum for main voltage without a series inductor, so I figure maximum charge of 1.61 coulombs applies up to 580 volts, at which point the energy is 467 joules, and that 467 joules can easily be withstood without a series inductor up to 610 volts. With more than 480 volts and no series inductor, the color is likely to be more bluish than desired for photography with daylight film or a digital camera whose white balance is set to daylight unless a filter is used. These flashtubes are unlikely to fire easily with 480 volts or less applied to them, so I recommend having the main energy storage capacitor "feed" a small capacitor of a few microfarads (that is in parallel with the lamp) through a diode (that can pass through the high discharge current), with this smaller capacitor also being "fed" through a second diode by a source of higher DC voltage of at least 600 volts. I cannot yet rule out the need for even higher voltage because the datasheet for the INP3-7/80A specifies use without a series inductor with a simmer current of 1.2 amps from a source of 1200 volts. (NOTE: Such simmering will necessitate water cooling.)

These flashlamps need a higher trigger voltage than most photoflash flashtubes do, 12 kilovolts for external triggering, although the lower pressure version may trigger reliably with 10 kilovolts. The datasheets for these flashlamps specify greater trigger voltages and other trigger specifications.

Datasheet for the INP3-7/80A in
Russian, PDF format.

Datasheet for the INP3-7/80A
translated to English, plain text format.

Datasheet for the IFP 800 in
Russian, JPEG format.

Datasheet for the IFP 800
translated to English, plain text format.

I thank Dr. Duncan Cadd in England for sending me these datasheets.

Estimated minimum energy to get half the ultimate efficiency is about 13 joules for the FXQ-1302-3, about 11 joules for the older FX-103C-3.

Estimated minimum capacitance for efficiently producing a continuous spectrum is 63 uF for the FXQ-1302-3 and 75-80 uF for the older FX-103C-3.

These flashtubes will safely work without inductors with lower voltages of 600-750 volts and energy levels at least up to 150 joules, and up to at least 300 joules with the FXQ-1302-3.

I publish guidelines for quartz linear xenon flashlamps here.

I mention these lamps in a separate file here because they have some design features of arc lamps, and they are typically used with instantaneous current mostly being less than 25 amps. They can be used as conventional flashlamps.

Written by Don Klipstein.

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