Many small tube 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 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 those doing shaped pulse tricks and/or using series inductors. All of the tubes below will work with the recommended voltages, energy levels, etc. without inductors so you don't have to worry about this unless you are doing something tricky.

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

Heimann's ratings are a minimum voltage of 270 volts, a nominal voltage of 300 volts, a maximum voltage of 350 volts, a maximum energy of 8 watt-seconds, and a 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 47 to 220 uF, preferably 100 to 180 uF. Smaller electrolytic capacitors will have excessive internal resistance which will reduce efficiency, but this is not as bad with Vishay/Sprague TVA series and similar axial lead ones as with other (especially more compact) aluminum electrolytics. Also, larger capacitance of aluminum electrolytics favors less ESR (effective series resistance). You also probably don't want to exceed .06 coulombs of charge or else electrode wear may be excessive. Nonelectrolytic capacitors can be efficient at lower values, but below about 47 uF or so, the spectrum will be less like that of daylight 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.

I tested efficiency at various energies at 280 volts. The efficiency is half that of the 8-joule level 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.

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 a minimum voltage of 250 volts, a nominal voltage of 330 volts, a maximum voltage of 360 volts, a maximum energy of 28 watt-seconds, and a maximum average power of 1.87 watts. Life expectancy at 28 joules and 330 volts is 1,000 flashes. I do 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 yet to do 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 a minimum voltage of 220 volts, a nominal voltage of 380 volts, a maximum voltage of 400 volts, a maximum energy of 36 watt-seconds, and a 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.

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 ratings: 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.

EG&G's ratings are a minimum voltage of 200 volts, a nominal voltage of 500 volts, a maximum voltage of 550 volts, a maximum flash energy of 6 watt-seconds, and a maximum average power of 6 watts. Life expectancy at 6 joules and 500 volts is 5 million flashes.

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

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 slide 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 tube 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 - and these figures vary a little from one brand or production run to another. Estimated Ko typically 11 ohms-amps^.5.

Nominal anode voltage 400 volts, 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. 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.

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, and I estimate roughly 470- 1000 uF 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 40 Torr or maybe a little less. 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.

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, 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.

Estimated energy requirement to get half the ultimate efficiency is 15-20 joules.

This tube triggers easily and does not need more than 4 kilovolts to trigger in my experience.

Approx. arc length 220 mm, tubing bore 6 mm, estimated xenon pressure 80 Torr, estimated Ko 28 ohms-amps^.5.

Estimated minimum capacitance for daylight-like largely continuous spectrum is 300 microfarads.

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 Torr, estimated Ko 11 ohms-amps^.5.

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

I have seen an energy rating of 2400 joules that I consider optimistic for a tube this size, considering the size of the electrodes. I consider 1200 joules more realistic and recommend not exceeding 400, maybe 500 joules if you want very long life with heavily repeated flashing.

I recommend mainly 500-700 volts, preferably 600-700 volts for this tube - lower for lower color temperature of hardly over 5500K, higher but no more than 700 volts for higher energy handling capability. I would also go easier on the energy with voltages under 600 volts.

Average power input - I can only guess 50 watts long term, maybe more especially if you hack off the outer tube (watch for nasty UV including shortwave!).

Projected energy requirement to achieve half the ultimate efficiency is 10-12 joules. Projected capacitance needed for a daylight-like spectrum is roughly 200 uF.

Approx. arc length 125 mm, tubing bore 5 mm, estimated xenon pressure 125 Torr (maybe 150), estimated Ko 25 ohms-amps^.5. Expect good efficiency with the xenon pressure being higher than that of many flashtubes!

Written by Don Klipstein.

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