Why not LED bulbs?

I've often wondered about the older Fluorescent condoms I assume the newer types are OK.

Depends on the age and technology used. My father's wrist watch has radium painted hands and glows in the dark come what may. Back then the old zinc sulphide green glow phosphors were a bit rubbish.

Tritiated plastic used for emergency exits and fishing floats is also hot (also in some LED watches the 1980's). Enclosed by glass the 19keV emission from tritium is more like a cathode ray than radiation.

The best modern phosphors will last all night - 3M made a really nice emergency torch that was made of very glow in the dark plastic. Charged in sunlight it was bright enough to see by once fully dark adapted.

And the same efficiency.

Bill

I had one that was, they used radium in the paint.

The radioactive watches faded over the years as they had a short half life. Tritium IIRC.

i have some 70W panels like bigclive tested and they are extremely bright.

much brighter than a 250w bulb.

odd shape though and only 12V.

Possibly. The fittings in my garage are at least 20 years old, probably older. There were in place when we bought the house and the conventional tube life is terrible- so much so that I started to wonder if they were T12 fittings and I was using T8 tubes.

I've only replaced one with an LED tube so far but the others will be replaced as they fail- I don't see the point in dumping working tubes.

I'll do the same in my electronics workshop. There the fittings were new about 18 years back. Those tubes have lasted well.

Sure, places where you would fit a specialist bulb like a fridge, or an oven, you'd continue to do so, but anywhere I'd put a bog standard bulb, I'd now put an LED.

IME of the last very few years, the LED stuff has surpassed the performance of any domestic filament bulb.

The "pseudo filament" stuff has taken off bringing a wide variety of "artsy" bulbs too. For candle stule, these filament string type actually put out very good light and Philips have some that even drop their colour temperature as you dim them - they actually feel really nice.

However, you get what you pay for - you can either get lucky with some el-cheapos anb even if they die after a year, you feel fine.

Or you can go with some of the better brands. I tend to write the install date in Sharpie on mine near the base.

Philips seem to last for years but are also the most expensive.

LEDHut seem to do a couple of years from a batch before the odd one starts to pop. Now they do have an extended warranty, but I find I never do the paperwork (it was an actual form) so that's pretty useless to me personally. However, IIRC their "no paper" base warranty is something like 2 years and I've returned the odd one and had a no fuss replacement.

Both LEDHut and Philips bulbs give (if you buy the brightest) exceptional light output and decent light quality. If you are an artist and CRI matters, you'll need to step up to a more pro bulb, but I prefer LED to filament in terms of light for light.

That is my 2p on the matter and it's worth about the same :)

The only filaments I have left are the 12V G4's in the bathroom - as I've not seen any dimmable LEDs I like (and I would have to find a PSU that didn't mind the pull cord dimmer that I have to assume is probably a leading edge old style triac jobbie).

Thanks all. These lamps will just be used for domestic (i.e. Non-specialised {cooker, fridge etc]) undimmed applications so there seems no real reason not to get an LED bulb.

Yes. Try putting an LED in your oven lamp holder.

Tim

Are you saying you can't tell the difference between these LED imitations and the real thing? I can.

Both CFL and LED have attempted to look the same. Perhaps that's why they haven't succeeded for everyone.

If all you want is light to see your way by, they're likely OK. Some may have extra requirements.

So your question is, do leds flicker? the problem of whether any kind of light flickers is an interesting one. I did see some old fashioned tubes with long persistence phosphor which meant, in theory, much less flicker, but when these were fitted onto a large area, like Tescos there appeared to be a kind of wave washing over the ceiling of the room, which made one feel very queasy. LEDs one supposes if in series and somehow half driven on each phase of the mains are going to flicker at 100 hz. maybe some kind of DC psu could be derived which was constant enough to make no flicker, but what of the wave effect? Is this due to different mains phases or what, I now have too little sight to test it. Brian

I never liked Halogen, the light seemed to be green to me, but remember I have always had an eye condition. Brian

I doubt that, but they are certainly less efficient as much of their output is heat. Brian

I agree. I have just fitted two G9 LEDs in the bog.

Do they? I though the semiconductor was gallium nitride, on a silicon carbide or aluminium oxide substrate, and the phosphor is often cerium-doped yttrium aluminium garnet (Ce:YAG).

There might be an infinitesimal amount of n-type doping, which can be arsenic, but it's tightly bound to the semiconductor lattice. A random source suggested roughly 10^16 atoms/cm3, which is about 1 microgram/cm3 of arsenic in the doped layer, which might be 200nm thick. So a doped chip might be 10^-16 grams of arsenic per cm2 of chip area.

Probably not worth breaking out the hazmat suits.

Theo