Re: Interupting xenon flash current ?

On Wed, 05 Dec 2007 16:48:10 -0500, Mike <nomtrxspam@xxxxxxxxxxx>
wrote:


I believe there is a mistake with your measurement. In the common
cameras, the flash current is at the order of 100A and the duration is
~tens of milliseconds. They handle it with IGBT of SOT-223 form factor.

However there are the special pulse tubes for use with lasers, etc. They
have higher rate of the current increase and the shorter flash duration.


Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com

That was my frst reaction also since I expected to see something less than 400A, but I can't find any reason
for such a major error.
I have a 200mv 200A shunt in series with the tube and am simply grabbing the voltage waveform across the shunt
with an HP 54502A storage scope. So with 1mv/A and reading 1.9v peak that's 1900A. I connected the 1V scope
calibrator output from an analog scope to 54502s input and it reads right on amplitude and time.


Current shunt inductance can be a serious error in this time domain. A
current transformer would probably be more accurate, and avoid ground
loops too.

1-turn primary, maybe 100 turn secondary on a ferrite toroid, 1 ohm or
less non-inductive burden resistor. We've done this in the 100 amp, 50
ns sort of range, on a node that kicks a kilovolt, and it worked well.

John





Mike
If there is no absolute truth then nothing can be known.

.

Relevant Pages

  • Re: Interupting xenon flash current ?
    ... have higher rate of the current increase and the shorter flash duration. ... I have a 200mv 200A shunt in series with the tube and am simply grabbing the voltage waveform across the shunt ... calibrator output from an analog scope to 54502s input and it reads right on amplitude and time. ...
    (sci.electronics.design)
  • Re: Interupting xenon flash current ?
    ... have higher rate of the current increase and the shorter flash duration. ... I have a 200mv 200A shunt in series with the tube and am simply grabbing the voltage waveform across the shunt ... expect to see 0V pulse when you fire the strobe...and check if you ...
    (sci.electronics.design)
  • Re: Interupting xenon flash current ?
    ... However there are the special pulse tubes for use with lasers, ... have higher rate of the current increase and the shorter flash duration. ... I have a 200mv 200A shunt in series with the tube and am simply grabbing the voltage waveform across the shunt ...
    (sci.electronics.design)
  • Re: Interupting xenon flash current ?
    ... Mike nomtrxspam@xxxxxxxxxxx posted to sci.electronics.design: ... the flash current is at the order of 100A and the duration ... They have higher rate of the current increase and the shorter flash ... connected the 1V scope calibrator output from an analog scope to ...
    (sci.electronics.design)
  • Re: Interupting xenon flash current ?
    ... the flash current is at the order of 100A and the duration is ~tens of milliseconds. ... They handle it with IGBT of SOT-223 form factor. ...
    (sci.electronics.design)
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