Bob Fickle wrote:
" I have " ...attempted to estimate how fast the filament will
heat up. From the description on JLN's web page, I estimate the
filament has a mass of about 1.2g, and would require about 200
Joules to heat from an average temperature of ~700K to the
"operating" temperature of 2000K."
I think the mass of the filament is much higher - closer to 10 g.
Did you look at the twin-lobed "filament temperature" chart on the
bottom of:
http://jlnlabs.imars.com/mahg/tests/lrtests.htm
This indicates to me that the filament is being heated by
something other than the electrical current at 5% duty cycle,
which must only contribute a small fraction of the total heating
(I wonder how that temperature was arrived at - did he use an IR
spectrometer? if so that means he probably has other spectroscopy
data which is not being shared.
"The input during the short pulses is much less than this. I
posted this calculation to JLN about 10 days back, but have no
reply as yet."
Nor will you, most likely. We still do not have a schematic of the
wiring, so everything thus far remains little more than
supposition.
Jones
