On Tue, 22 Dec 2020 10:48:39 +0000, The Natural Philosopher
wrote:

On 21/12/2020 22:56, Cursitor Doom wrote:
On Mon, 21 Dec 2020 20:57:55 +0000, The Natural Philosopher
wrote:
?
Well I am only guessing, but Id say that the same inductor that limits
tube current limits the LED current and with enough in series you can
make up the voltage, or not, as you prefer. .

I'm really struggling to see how the tube supply would be remotely
compatible with LEDs. Tubes are voltage operated devices,

Well no, they are not. Almost exactly the reverse in fact

The thing about a tube is that it is a gas discharge tube, and needs a
fair voltage to *strike* , and the assistance of some cathode heaters,
but once struck it will draw (almost) unlimited current, at a
(constant) voltage IIRC of about 70. The inductor serves to limit the
current.

Irrespective of what the voltage across the tube is. You could replace
the tube with a dead short and it wouldn't trip anything - the inductor
limits the current.

And what that means is that any fairly low impedance load will get the
same power delivered. By what amounts to a constant current source
comprised of the mains and the inductor. And the fact that the LED and
Fluoro efficiencies are similar, means that an LED array fed by such a
source will draw virtually the same or similar power and be of
equivalent brightness in so doing

I have no idea how that current is apportioned to each LED. Or how many
there are. IIRC a whte LED is 4V or so, so to get to no more than 1090V
you wouldn't want more than 25 in series, and you would need a bridge
rectifier. Or perhaps you could have two chains in opposite polarity, to
make use of each half cycle. flickery tho.

I think I'd run a series of rectifiers and caps to drive different
chains and put the chains in parallel. Hmm. No that doesn't work
...possibly if enough diodes are in series the average v drop evens
out...a you can simply out the chains in parallel

These modern lighting LEDs are becoming further and further removed
from the small signal devices they evolved from, so I'll bow to your
superior knowledge on the subject. I'm very much more
electronics-orientated than electricity, anyway. You say these LEDs
have a 6V Vf and that is ten times the voltage I would expect to see
from the SSD legacy so clearly I'm well out of date with developments
in lighting technology!

Next time you are passing then. I do good coffee also.

And I do pretty good advice on tax mitigation. Let's hope we're both
still around a year from now, because I can't see myself getting over
to England anytime soon, what with the way things are going.