"No-fire current" for flash bulbs?

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Well-Known Member
Feb 11, 2003
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Hi all,

Does anyone out there have no-fire/all-fire characterization data for flash
bulbs, specifically AG1/AG1b?

I am trying to improve my launch controller design to be "flash bulb safe"
but solid data on the above is proving elusive.

I found one mention on the web that "5 mA" is flash bulb safe, but when I
did my own test it took around 220 mA to fire, so I suspect the 5 mA is way
too conservative. OTOH, I don't know what the manufacturing variabilities
are. I'd rather not burn up my stock of bulbs to find out if the data is
already available somewhere.

I have never felt enough of an urge to do the testing to round up the 80 or so flashbulbs testing would require.

I suspect that the no fire current would be fairly low based on the likelihood that the variance in firing currents would be high.
I did some testing decades ago and the steady state no fire current is higher than one would think; well over 200mA. The caveat is that it takes a small amount of system capacitance to cause a current surge to fire them. How do I know this? When I was testing the no fire current, I was using a variable voltage and current source. I started in a current limited state and slowly increased the current to the limit of the power supply. I disabled the output, then enabled it and the bulb fired.

Another interesting fact is that the IR emission of a flashbulb firing will set off another flashbulb if it's closer than ~1/4"
And now, 16 years later, we still have no data ?

Dave F.
Not surprising really, as not many people use flash bulbs for deployment or staging anymore with the advent of Quest Q2G2's and or cheaper and readily available ematches.

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