"Jim Lesurf" wrote in message
...
In article , Arny
Krueger
wrote:

"Phil Allison" wrote in message
...

"Arny Krueger"

No, if you are observant the phosphor coatings in many fluorescent
bulbs have considerable latency and take the better part of a minute
to come up to full brilliance when power is applied or die out when
power is removed.

** Fraid that is not due to the phosphors having large latency, but
simply to the temperature of the tube and the mercury vapour inside.
Once warmed up a bit, full efficiency is achieved.

On reflection, there has to be at least some of that at work.

My understanding is that the electrodes and vapour/gas take orders of
magnitude longer to warm up than any decay responses in the phosphors.

The light output IS modulated at twice the line frequency and produces
stronger strobing of spinning objects than incandescent lamps do.

I'm aware of that effect but the blurring of the strobe lines says that
the modulation is less than 100%.

One of the teaching lab experiments I did decades ago involved measuring
the light output, etc, of fluroescent tubes. The ballast/striking does
tend
to give an 'on : off' flattening over each half cycle and the 'off' is
short compared with the 'on'. But the depth of modulation is much bigger
than for an incandescent. However this is all a recollection from
measurements in a past decade, so I have no idea now of the values or
exact
light-time curve shapes.

Given the above, I often in later years found that optical filtering was
required to stop wideband sensors from being affected by the 100Hz from
flouroescent tubes. (This was with the ancient 'Golay' detectors that
picked up from UV to a few tens of GHz. I suspect no-one uses them now.)


The actual reliable fact that I know for sure is that when afflicted by
heavily modulated AC power, fluorescent lamps were the only place I could
stand to read. I presumed it was due to the phospors because of my
electronics background.