Well the issue of course is that they have no thermal persistence as most of
the filament bulbs do and presumably go out completely when zero is
crossed. I'd have thought in this day and age they would have been able to
sort this out electronically, though of course if they did use a switch mode
solution the crud put out in the RF area might be rather bad.

Brian

--
From the Sofa of Brian Gaff Reply address is active
"Colin Stamp" wrote in message
o.uk...
Hi all,

I tried out some Ikea LED candle bulbs today, wondering if 90 lumens
would be enough:-

http://www.ikea.com/gb/en/catalog/products/30217927/

I thought I was impressed. 90 lumens turned out to be a little bit on
the dim side, but they look quite reasonable in the fittings, which were
intended for halogen candles. The light comes out in about the right
places IYSWIM, The colour is fine and they're cheap.

Then came the realization. The sodding things strobe really badly. Now
I've noticed it, I can't get away from it. Anything that moves in the
room turns into bloody set of freeze-frames, as does the whole room
every time you move your eyes!

Is this a common thing with cheap LED bulbs? I'm all worried about the
impending Ebay purchase of Chinese replacements now. The only other LED
bulbs I've got are two brands of GU10 and they're fine, so maybe it's
just Ikea ones that are crap...

Cheers,

Colin.

On 27/02/2013 09:15, Brian Gaff wrote:
Well the issue of course is that they have no thermal persistence as most of
the filament bulbs do and presumably go out completely when zero is
crossed. I'd have thought in this day and age they would have been able to
sort this out electronically, though of course if they did use a switch mode
solution the crud put out in the RF area might be rather bad.

Brian


They are usually switch mode. The ones I've seen run at a few tens of
kHz, but there is still the 100Hz pulsing of the rectified mains supply
to contend with. If it isn't smoothed before driving the switcher, then
the switcher will die and restart every half-cycle. It only takes a
capacitor to bridge the gaps, but it seems Ikea saved some money...

Cheers,

Colin.