Thanks David! The oscilloscope idea is brilliant. It will also give me a
curve!
I must find someone here who has one
OR
AT LAST an excuse to buy one?
Herschel
On 1/28/11 9:48 AM, David Dyer-Bennet wrote:
On Fri, January 28, 2011 05:00, Christopher Strevens wrote:
Flash duration is about 1/10000 sec. I would think a bullet from a gun
that
has just been fired. Use a wire to hold the flash off so it triggers as
the
bullet breaks the wire. The circuit would be a transistor going to ON to
fire the flash and an transistor I the inverting amplifier configuration
holding the flash fire transistor off until the wire is cut.
The muzzle velocity of you gun should be available from the gun smith and
so
the length of the blur will enable you to compute the duration of the
flash.
Warning! Guns are dangerous so don't shoot yourself or anyone else during
the measurement. You will need a couple of sandbags to safely stop the
round.
Using an air gun is somewhat easier, in that you don't need as heavy a
backstop, and the legal complications aren't as messy.
With a real gun, the muzzle velocity varies with both the gun itself, AND
the ammunition. However, if you know anybody who reload seriously, they
probably have a chronograph to measure how their ammunition is performing,
so you could use that to get a fairly accurate reading on the bullet
velocity, and then in turn use that for measuring your flash duration.
At this point, however, it might be easier to find somebody with an
oscilloscope instead, hook up a photocell and power source to it, and just
expose the photocell to the flash.
