On Mon, 24 Jun 2002, Brendan Moran wrote:

>You know the resistor is 10ohms, right?  Well, why not do this:
>
>Integrate the waveform over the duration of a single flash sequence, then
>square the result, and multiply by 10 ohms, then, as long as you carry the
>units through, you have an output in watt-seconds^2  sot hen divide by the
>time it takes for the strobe sequence, which gives watt-seconds, which is
>what you wanted, right?
>
>Caveat: I haven't done power analysis of strobes before, I'm just looking at
>the unit analysis, I could have made a critical error somewhere in there.

Or even better glue a thermistor to the resistor and run the flash until
the readout (ohms) is stable. Then disconnect the flash supply and connect
a benchtop PSU across the R and set it until you obtain the exact same
reading. If the resistor operates at 10-20 degrees above ambient then this
will be fairly accurate. Make sure that all covers etc are in the same
position with the benchtop and with real operation OR remove the R on a
pair of wires. The idea is to achieve the same conditions for both tests.
The thermistor needs no calibration.

Peter

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads