2700K is nearly filament bulb color, 4000K is called warm daylight,
6500K is called cool daylight.
A friend makes aviation tower warning lights, they need to be reliable, so I am well aware of what is practical and what is not.
And we have supplies of ceramic base LEDs at another factory, they look a bit like the ones in your photos, and run on mains, the driver is part of it.
Practical aspect is making a lamp, heat sink, housing, driver if needed.
For a 2 dollar item, not really worth it for me.
The direct drive emitters are 50 cents for a 3W unit, 30W is about 3 USD...
6500K is called cool daylight.
A friend makes aviation tower warning lights, they need to be reliable, so I am well aware of what is practical and what is not.
And we have supplies of ceramic base LEDs at another factory, they look a bit like the ones in your photos, and run on mains, the driver is part of it.
Practical aspect is making a lamp, heat sink, housing, driver if needed.
For a 2 dollar item, not really worth it for me.
The direct drive emitters are 50 cents for a 3W unit, 30W is about 3 USD...
Naresh, are you the same guy that was trying to equate exploding carbon fiber wings to a freaking speaker baffle? How old are you, serious question? If you're a young buck that has a pension for reading whitepapers then I applaud your tenacity. But if your like, say 25, just give it a rest. This is gamma behavior. Let's set some ground rules: Osvaldo dislikes LEDs. I say "but wait, what about this" and you come in, IN MY EXPERIECE WITH YOU, to proffer a contradiction. I say "OK, tell me more" and you don't deliver. I call you out, and you lash out. Do I have this right?
Wrong guy...I use speakers.
No idea about exploding speaker baffles.
I think you have somebody else in mind.
See my profile for more information.
No idea about exploding speaker baffles.
I think you have somebody else in mind.
See my profile for more information.
Fair enough.
I'm gonna add this caveat: If you come to my thread like 'exploding carbon' dude, expect an absolute savaging! I say this with love my guy.
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I think they base it on time of day and position. Huge grain of salt here because I haven't read up on it in years..........the sun emits a full spectrum of light, so you can arbitrarily grab whatever wavelength you want from it. It's not a very useful metric. BUT.... the color temperature helps immensely in that high temps become "cooler" (an ironic contradiction) as they in increase in Kelvin. So as you go higher you get into the nasty blue tints you find with cheapo lighting. As you reduce color temperature you begin to approach closer approximations of an actual candle flame. I don't recall what the color temp of a candle flame is (maybe Naresh will look it up to contradict me; just kidding Naresh 🙂, but it's probably close to the range of 1500-3000 Kelvin. A candle is COZY. Everyone inherently appreciates this. The problem with the sun alone is that it can render candle temps, UV, IR, literally everything ( I stand to be corrected here).
So if you approximate the sun at 6500 Kelvin it doesn't mean jack shid. No one wants to be in a blue incubator but the sun can crank that out no problemo. Humane light is warm, i.e. close to a cozy mantle of candles on a hearth. In other words a low temperature. The sun creates the cozy effect at different times of day. CRI (color rendering index) is based on the accuracy that a LED can match proximity of the sun at different temperatures. So high color temps are irrelevant because no one wants to live under a bug lamp, except Naresh (OUCH). I'm gonna send you some proper LEDs Naresh.....
Edit: it just so happens that the higher the color temperature, such as 6500k [which is bleeding eyes/migraines high], the more efficient an emitter ( or tube assumedly) will operate. So the more humane, high quality, non bugman the lighting gets, the less efficient it is. You can't compare a 6500K tube against a 2700K LED. It's a BS comparison-- as mentioned previously, it's like class B vs class A.
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The most led lights here are Baw. Seems to be the worse or almost. I have collected some of them found in the thrash to recover inductors' core (they have a square loop ferrite to make the self oscillating half bridge to work). Most of them had the leds darkened by internal failure. Several of them failed in the very first hours as reported by my friends.
But personally I dislike led light. They are OK for indicators but not for room lighting. And also I wont modify all my set to accomodate them. My EM ballasts are over the ceiling and to rewire it is a big headache. As they are IRAM approved (a local regulation agency like UL or similar) they don't buzz/hum. And HF (3~30MHz) is clean (or relatively clean) with they turned on or off. Again, street lightning (Philco branded) interferes up to 150MHz. Definitively don't want them at home.
But personally I dislike led light. They are OK for indicators but not for room lighting. And also I wont modify all my set to accomodate them. My EM ballasts are over the ceiling and to rewire it is a big headache. As they are IRAM approved (a local regulation agency like UL or similar) they don't buzz/hum. And HF (3~30MHz) is clean (or relatively clean) with they turned on or off. Again, street lightning (Philco branded) interferes up to 150MHz. Definitively don't want them at home.
Fluorescent tubes and LEDs are now very similar. Both use a short wavelength light source (blue LED or ultra-violet ionised mercury vapour) that is down-converted to "white" by suitable phosphors. And it's those "suitable phosphors" that are key to the quality of the light. When you buy a fluorescent fitting, it comes with the very cheapest tube possible because the manufacturer is not in the business of making fluorescent tubes. It's cheapest simply to use phosphors that produce three peaks (red, green, and blue) that mixed in the right proportions fool the eye's receptors into thinking it is seeing white light. But these are narrow peaks with little broadband radiation. So when you view coloured objects (resistor colour codes), the colours are not correct. And that's where the CRI (Colour Rendering Index) mentioned earlier in this thread comes in. If you use better phosphors, you can increase the broadband radiation at the expense of the peaks and the CRI goes up. Cheap fluorescent tubes have a CRI of 0.7, whereas the better ones (Osram Biolux, Sylvania Activa 172) are 0.95. They are also used for treating Seasonally Affected Disorder. You won't find them in your DIY store, but an electrical merchant can order them for you without any problem. And they're only a little more expensive than rubbish tubes. The downside is that the higher CRI phosphors tend to be slightly less efficient. When LED lights were first introduced, their CRIs were so bad that they were unstated. They are now around 0.7, but there may be better ones.
So, what to do? People have become conditioned to liking the light from incandescent filaments, which is typically 2700K. In a workplace (workshop, kitchen, etc) 4000K is better for seeing what you're doing. It's always better to have a high CRI. If you need correct colour rendering, you need a high CRI and 6500K (overcast Northern sky). I've replaced my workshop mercury vapour fluorescent tubes with LED fluorescent because power consumption went from 58W to 20W per tube. OK, the colour rendering isn't as good, but that's not essential when drilling a hole.
It used to be essential to use an HF ballast to eliminate flicker, but fluorescent tubes using LEDs must include a switcher, so that should take care of the flicker problem.
Most of the criticisms people make about fluorescent tubes are due to suffering tired cheap tubes powered via choke ballasts...
So, what to do? People have become conditioned to liking the light from incandescent filaments, which is typically 2700K. In a workplace (workshop, kitchen, etc) 4000K is better for seeing what you're doing. It's always better to have a high CRI. If you need correct colour rendering, you need a high CRI and 6500K (overcast Northern sky). I've replaced my workshop mercury vapour fluorescent tubes with LED fluorescent because power consumption went from 58W to 20W per tube. OK, the colour rendering isn't as good, but that's not essential when drilling a hole.
It used to be essential to use an HF ballast to eliminate flicker, but fluorescent tubes using LEDs must include a switcher, so that should take care of the flicker problem.
Most of the criticisms people make about fluorescent tubes are due to suffering tired cheap tubes powered via choke ballasts...
Because the eye/brain performs an automatic colour balance to compensate. It's similar to the ear/brain performing a balance so that when you talk to someone you know outdoors and walk indoors, their voice sounds unchanged, yet the acoustics have changed dramatically.
As a corollary to that, TV studio lighting is 2700K and the cameras are balanced to match. But if a monitor is in shot, it has to be colour balanced to look right on camera, and it then looks very odd when you wander in and see it.
We do tend to underestimate the amount of processing it takes to do vision. Color itself is an abstraction - it doesn't really exist in the world outside our heads. We also generate a rectilinear world model from a spherical eyeball. Pretty amazing processing power, and with a latency of only about 200 milliSeconds.
All good fortune,
Chris
All good fortune,
Chris
Exactly this. I don't know if they still make them but there was a "remote phosphor" disc that purported 98 CRI when used in conjunction with high power blue LEDs. The problem was getting the high power blue LEDs. I was all excited about them an bought a set of the discs but never had much luck getting what I wanted from the light. It wasn't until the MFGs dialed in their phosphor coatings that the light quality reached acceptable levels and that is not very long ago. Although I don't put as much weight on CRI as I used to. I have some 80 CRI CREEs that are about the best I've come across.