A couple years ago EDN had an article on the SMPS in CFL's -- the levels of radiation are quite high and there wasn't enough room to properly attenuate the interference they generate -- things may have changed since that time.
Radiation is all over the lot with some folks reporting that the interference can afflict a variety of other devices.
Drifting completely off topic...
Once set, I don't believe the sound compression alters with statistical multiplexing. The audio bit rate is piddling compared with the video.
The audio is MP2. Bit rate varies from 32Kb/s mono to 256Kb/s stereo.
Proper channels use between 128Kb/s and 256Kb/s for the main audio stereo pair. That makes the audio quality significantly better than UK DAB for both TV and radio stations.
Before anyone comments that the sound was better in the "analogue days", sound distribution over links has been digital for over 35 years in the UK. PWM sound was inserted into the picture horizontal sync period to save money. The difference now is the lossy compression. Whether that is worse or better than the previous methods of torturing the audio is a matter for debate.
The irony is that there are now lossless compression systems barely "fatter" than 256KB/s but the standards are set.
Once set, I don't believe the sound compression alters with statistical multiplexing. The audio bit rate is piddling compared with the video.
The audio is MP2. Bit rate varies from 32Kb/s mono to 256Kb/s stereo.
Proper channels use between 128Kb/s and 256Kb/s for the main audio stereo pair. That makes the audio quality significantly better than UK DAB for both TV and radio stations.
Before anyone comments that the sound was better in the "analogue days", sound distribution over links has been digital for over 35 years in the UK. PWM sound was inserted into the picture horizontal sync period to save money. The difference now is the lossy compression. Whether that is worse or better than the previous methods of torturing the audio is a matter for debate.
The irony is that there are now lossless compression systems barely "fatter" than 256KB/s but the standards are set.
LED lighting still has a way to go, the quality is there if you're prepared to pay for it and that's where the problem lies. CREE have continued to drive down the price of their LEDs helping to increase their economic viability, but they are still far too expensive to be realistically considered by the general public.
It doesn't help that there's the cheap Chinese knock-off stuff all over ebay giving LED lighting a bad name. I purchased a couple of MR16 replacements and as Wavebourn said they were indeed 'dead white' the light looked like puke. I ripped out the insides and replaced them with some OSRAM golden dragon LEDS I'd picked up cheap from ebay, now those look great.
It doesn't help that there's the cheap Chinese knock-off stuff all over ebay giving LED lighting a bad name. I purchased a couple of MR16 replacements and as Wavebourn said they were indeed 'dead white' the light looked like puke. I ripped out the insides and replaced them with some OSRAM golden dragon LEDS I'd picked up cheap from ebay, now those look great.
I have a long flexible strip of LEDs as under counter light in the kitchen. I love it. It's basically a 20 foot long, 1/4" wide PCB. It has a SMD LED and resistor about every inch. It gives a very even light, is tiny and was super easy to install. Draws about 25 watts. Runs of a 12V SMPS.
Bought it last year. This year I bought another 3 feet to extend it a bit. The new strip looks the same, but the light is warmer and brighter. Certainly a change for the better, if not a direct match. Progress is being made.
Bought it last year. This year I bought another 3 feet to extend it a bit. The new strip looks the same, but the light is warmer and brighter. Certainly a change for the better, if not a direct match. Progress is being made.
Back on topic
I've tried LED lighting and agree with Pano that the under-counter kind is good. I bought mine from Ikea - far from the cheapest, but at least there's a returns policy.
Regarding Cree: They are making some of the best high power LED's but I have had failures, I think, due to inadequate heat-sinking in the fitting. They really did get hot and lasted just over a year (the warranty period) before failing.
All the high power LED lights I've come across use white LED's. As previously stated these come in "cold white" or "dead white", and have a close spectral similarity to those awful CFL's. I suppose this is because the white LED's also use a phosphor. I can't wait for some proper high power RGB LED's that are affordable.
I've tried LED lighting and agree with Pano that the under-counter kind is good. I bought mine from Ikea - far from the cheapest, but at least there's a returns policy.
Regarding Cree: They are making some of the best high power LED's but I have had failures, I think, due to inadequate heat-sinking in the fitting. They really did get hot and lasted just over a year (the warranty period) before failing.
All the high power LED lights I've come across use white LED's. As previously stated these come in "cold white" or "dead white", and have a close spectral similarity to those awful CFL's. I suppose this is because the white LED's also use a phosphor. I can't wait for some proper high power RGB LED's that are affordable.
And that helps to highlight where I feel LED lighting is falling down, that is LED replacement bulbs. This isn't where an LED is typically best suited, the best thing to do is design a complete light, such as the under-counter kind where there are no constraints with regards to design in getting them to work properly. CREE has it's own complete lighting fixtures and these show the direction things should be going in, do away with the reaplacement bulb and introduce new lighting designs.
The LEDs however are quite fragile, both in terms of physical damage and thermal damage. Physical damage is usually only encountered during the construction phase, but you can apply pressure to the wrong part of the LED with your tweezers and damage the tiny lead-out wires embedded in the silicone.
Thermally LEDs are easy to damage and this is usually caused during the initial soldering process. You cannot really solder these things by hand unless you are using a low temperature iron and even then its risky business. I am sure this is the reason why I've encountered some premature failures (even with the low temp iron), but using a hot air gun/oven + solder paste has pretty much solved that (so far). Over temperature during the soldering process doesn't always cause an instant failure either it takes some time before this becomes apparent.
Most of CREEs LEDs will easily function at junction temperatures of 85 degrees, if not higher when you're considering the 25-35,000 hour LM70 specs. If you've semi-damaged an LED during the soldering process they will die quickly when run at high temperatures or at their rated current.
I have a light I built last October that uses four XPGs run at 1amp and those still work great. One of the LEDs failed but that was due to my own ignorance and now I know better
What LED series was is that you used dhaen?
The LEDs however are quite fragile, both in terms of physical damage and thermal damage. Physical damage is usually only encountered during the construction phase, but you can apply pressure to the wrong part of the LED with your tweezers and damage the tiny lead-out wires embedded in the silicone.
Thermally LEDs are easy to damage and this is usually caused during the initial soldering process. You cannot really solder these things by hand unless you are using a low temperature iron and even then its risky business. I am sure this is the reason why I've encountered some premature failures (even with the low temp iron), but using a hot air gun/oven + solder paste has pretty much solved that (so far). Over temperature during the soldering process doesn't always cause an instant failure either it takes some time before this becomes apparent.
Most of CREEs LEDs will easily function at junction temperatures of 85 degrees, if not higher when you're considering the 25-35,000 hour LM70 specs. If you've semi-damaged an LED during the soldering process they will die quickly when run at high temperatures or at their rated current.
I have a light I built last October that uses four XPGs run at 1amp and those still work great. One of the LEDs failed but that was due to my own ignorance and now I know better
What LED series was is that you used dhaen?
Hi,
LED's are here. In the new place I just moved to I did all lights with Led's. I liked "warm white" better than sodium yellow of those cold cathode lamps
Lots of 1W spots and downlighters with lense in E27 and some 3W 'lightbulb imitations' in the ceiling lamps.
Works fine. Will see the difference in the bill in a bit...
Ciao T
LED's are here. In the new place I just moved to I did all lights with Led's. I liked "warm white" better than sodium yellow of those cold cathode lamps
Lots of 1W spots and downlighters with lense in E27 and some 3W 'lightbulb imitations' in the ceiling lamps.
Works fine. Will see the difference in the bill in a bit...
Ciao T
That's the way they want it, fine. There is an old oil lamp in my mother's garage, belonged to my great-grandfather, that happens to be 100+ years old, with a glass globe intact, doubtful it's the original globe, but it works great and outputs luminosity close to an incandescent, simply cover with a lampshade. Easy to control brightness by adjusting the wick knob. It looks like I may have to put it back to work.)
Here in California they invented "Clean Air", to fine those who want to burn something during cold nights.
The LED strip I bought runs very cool because there is so much space between each element. They came on a spool and that got warm very fast, as they were all laid on top of each other. Unrolled, not problem.
This is what I bought and highly recommend:
LED Strip Lights Wholesale - LED Strip Light Spools - ElementalLED.com
I did not feel the need for the more expensive high density strips, the regular is just fine.
The hoop-la about the death of the incandescent is funny to me. Like everything will be CFL. Not! You can buy the same size and shape bulb as your old 75W, 100W but the have a halogen lamp inside. Same light for fewer watts. Lasts long too. or should. The light is whiter, but I don't mind that. They are perfectly legal under the new regs.
But people love to get upset about things and rant and rave. Not having the facts makes it even more fun. Silly.
This is what I bought and highly recommend:
LED Strip Lights Wholesale - LED Strip Light Spools - ElementalLED.com
I did not feel the need for the more expensive high density strips, the regular is just fine.
The hoop-la about the death of the incandescent is funny to me. Like everything will be CFL. Not! You can buy the same size and shape bulb as your old 75W, 100W but the have a halogen lamp inside. Same light for fewer watts. Lasts long too. or should. The light is whiter, but I don't mind that. They are perfectly legal under the new regs.
But people love to get upset about things and rant and rave. Not having the facts makes it even more fun. Silly.
I actually used MR16 fittings similar (but not identical) to those shown on this page:
Cree LED Spotlights - Lighting
Now I'm not sure whether Cree make just the LED's or the whole thing. At worst you could have good LED's in a bad assembly, in a bad fitting.
You are right that the only way to get good results is to design the whole luminary from the ground up.
I have been using LED lighting for specific purposes almost since the "white" versions came out. These days I can buy off the shelf power supplies for voltage to current that are UL rated. That allows me to use LED lighting in even more places.
BTY the electric bill for my house is usually less than $25.00 each month. My clothes dryer is electric, but my heat source is a high efficiency 80 gallon hot water heater. That requires a fan during heating cycles. Most "cooking" is done with a microwave oven.
Now a 100 Watt light run 24 hours a day would cost me almost exactly $10.00 a month.
BTY the electric bill for my house is usually less than $25.00 each month. My clothes dryer is electric, but my heat source is a high efficiency 80 gallon hot water heater. That requires a fan during heating cycles. Most "cooking" is done with a microwave oven.
Now a 100 Watt light run 24 hours a day would cost me almost exactly $10.00 a month.
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What made me comment re LEDs, is I needed some red lights with even distribution for a photographic darkroom. Spectrum seems ideal. Bought using the published specs as a guide, and found they were far too bright. (M16) Had to reduce supply current and add filters as well, (also red-just because I had it).
The real problem is the discontinuous spectrum of LED 'incandescent replacements'; these things are still essentially blue LEDs with added yellow phosphor to balance the obvious blueness; the 'warm white ones just add more yellow - but the wretched things are very deficient everywhere else in the spectrum. A bit like a cheap hifi 'system' with a loudness button but woeful midrange.
If you want to throw large amounts of money at the problem then yes , LED can provide superb light. I recently specced some LED Operating Theatre lights for surgical use, which achieve over 99% colour rendering and indeed have a separate adjustable red spectrum components so the surgeon can achieve maximal contrast on organs during surgery. 120,000lux on the surgical field is achievable, which is staggering ( = 2 x mean diffuse sky illuminance i.e. 2x daylight.)
The real driver here is less heat; the LED light system uses150W as opposed to 800W for the equivalent halogen units. This is surgically significant for several reasons. Definitely Not cheap though...
If you want to throw large amounts of money at the problem then yes , LED can provide superb light. I recently specced some LED Operating Theatre lights for surgical use, which achieve over 99% colour rendering and indeed have a separate adjustable red spectrum components so the surgeon can achieve maximal contrast on organs during surgery. 120,000lux on the surgical field is achievable, which is staggering ( = 2 x mean diffuse sky illuminance i.e. 2x daylight.)
The real driver here is less heat; the LED light system uses150W as opposed to 800W for the equivalent halogen units. This is surgically significant for several reasons. Definitely Not cheap though...
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I think this is perhaps over stressing the issue just a tad as they don't just throw yellow into the mix to drown out the blue, the phosphor coating emits a spectrum of light across a fairly large range of wavelengths and a decent quality warm LED will give you a CRI of ~80 (which is on a par with CFLs and significantly higher then the 'cooler' white fluorescent tubes). From my experience the quality of light that these give out is excellent, maybe I'd change my mind if I compared them directly to an incandescent bulb, but I haven't used one of those in years.
Actually one of the reasons I like well designed LED lights is you can vary the spectrum.
In my paint booth I can go from a decent CRI to what is called Arctic, more of the UV end of the range. Shows up flaws a bit better.
I'm not so concerned about 100W light bulbs as I am about smaller bulbs used in a variety of applications. I'm having a hard time finding a bulb for my microwave as is. I hate to of think how difficult it will be in 5 years.
Bulbs for normal lighting (in the USA) are standardized as mainly 60W, 75W, 100W, and three way 150W bulbs.
The variety of other bulbs is astounding. I seriously doubt there will be LED replacements for all.
Bulbs for normal lighting (in the USA) are standardized as mainly 60W, 75W, 100W, and three way 150W bulbs.
The variety of other bulbs is astounding. I seriously doubt there will be LED replacements for all.
It is possible that 5 years later when you ask about a bulb for microwave you'll get an answer like, "Huh? What's a microwave?"
LEDs with good CRI and CCT are coming . I work for a 'large company' doing just that - the US market already has our bulbs. It looks like a lightbulb, it quacks like a lightbulb, and I use them to light my living room, bedroom, bathroom... Sadly the ones I have are engineering samples at 4000K CCT, but the 3000K ones look fantastic.
But, for my mancave, I want a surgical or dental lamp, fired with HIDs. Light from 'lightning'!! And, the retail grade ones have CRIs of 90+
L
. I work for a 'large company' doing just that - the US market already has our bulbs. It looks like a lightbulb, it quacks like a lightbulb, and I use them to light my living room, bedroom, bathroom... Sadly the ones I have are engineering samples at 4000K CCT, but the 3000K ones look fantastic.But, for my mancave, I want a surgical or dental lamp, fired with HIDs. Light from 'lightning'!! And, the retail grade ones have CRIs of 90+
L
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