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Bert22306
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Government mandates also help lower the price
Bert22306   3/19/2014 4:04:46 PM
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In spite of the strenuous objections from those with libertarian leaning, I was looking forward to the gradual ban on higher powered incandescents. Reason being, this spurs innovation and also guarantees economies of scale. And that in turn would end era of the transitional CFLs sooner rather than later. Browsing though the light bulb shelves at Lowes and Home Depot has become fun again. All good.

I think one very important ingredient in LED development will be to make that power supply circuit as sparse as possible. And it's gratifying to see this happening.

kadawson
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Re: Government mandates also help lower the price
kadawson   3/19/2014 5:44:33 PM
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Agreed, we're going to see increasing focus on the driver side of LED lighting. When luminaires are tested to destruction, often it is the driver that fails first. While we know how to predict the useful lifetime of an LED, the same is not (yet) true of a driver.

Caleb Kraft
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HCL
Caleb Kraft   3/19/2014 4:27:15 PM
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Is human centric lighting really an advancement in the LED industry? I mean, doesn't most of it apply to incandescents and flourescents as well?

kadawson
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Re: HCL
kadawson   3/19/2014 5:42:29 PM
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True enough, but HCL comes into its own in the LED era. Incandescents and fluorescents can't behave as flexibly as LEDs with respect to control of color (and spectrum). Also, the inherently directional light of LED sources is easier to direct precisely where it's needed, to the benefit of humans, other creatures, and dark skies.

LarryM99
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When does it diverge?
LarryM99   3/19/2014 7:10:00 PM
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The first LED lighting for general consumer use was strictly replacement, built to screw into light sockets. I am starting to see more imaginative use of what is a fundamentally different light source, but it seems like there is room to really diverge. Can we build them into walls, maybe with electronic steering of the beams? Can we paint them onto surfaces and have them change colors as our moods dictate? What else might we want to do with them?

Duane Benson
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Re: When does it diverge?
Duane Benson   3/19/2014 7:32:10 PM
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Larry - I think you've hit on the really revolutionary potential. A big part of the need for the Edison base was simply the frequency that bulbs needed to be replaced. When significantly greater life span is reliably avaialble, the game changes. They can be put in essentially innacessible places and can be used in ways that incendescents never could.

prabhakar_deosthali
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Supply frequency
prabhakar_deosthali   3/20/2014 3:53:02 AM
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With LEDs working on their own driver circuits at some DC voltage levels, with many of the modern appliances working on inverters that convert AC to DC and aganin back to AC at a desired frequency , I think it is now time to relax those Frequency norms on the grid elelctric supply ( 50 or 60 hz +- 2% ).

 

Does it really now matter at what frequency the grid electricty is supplied? May be I am missing something!

GeniusEE
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Re: Supply frequency
GeniusEE   3/20/2014 6:27:22 AM
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prabhakar_deosthali   3/20/2014 3:53:02 AM: "Does it really now matter at what frequency the grid electricty is supplied? May be I am missing something!"

----------

 

You might want to revisit your freshman year AC Machines class notes

Bob Marso
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LED's and Color
Bob Marso   3/20/2014 1:13:08 PM
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One performance specification that held back CFL's acceptance was their poor ability to correctly illunimate the full spectrum of color in our houses.  Our spouses fought CFL's in the living room because they made the living room look like it had jaundice or some liver disease.  LED's are capable of overcoming this - after all the most accurate color rendering of computer images is obtained on LED backlite displays, not florescent backlite displays.

Knowing the color temperature of a light source (measured in degrees Kelvin) is not sufficient to select a good light bulb. The measurement of how wide a color spectrum a light source can accurately display or illuminate is the Color Rendering Index, or, CRI.  The closer to 100 you get, the better the light source.  CRI's in the low 90's are considered the minimum for good color illumination.  I'd like to see all manufacturers of interior lighting sources, no matter what kind, required to specify the color temperature and CRI on their packaging.  This would allow we the consumers to select the best light source and also up the competition among manufacturers to produce a better product.

GeniusEE
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Re: LED's and Color
GeniusEE   3/21/2014 12:13:16 AM
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Motherhood and apple pie

"Best" is worthless in a commodity, non-luxury, market, where good enough is good enough

High CRI means low efficacy. The name of the game with LEDs should be energy use reduction, not spec idealism that poisons the environment.

What held back CFLs initially was that they were expensive.

AZskibum
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Re: LED's and Color
AZskibum   3/23/2014 10:37:14 AM
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Excellent point. A big factor in my motivation to transition my home lighting from CFL to LED (still a work in progress) was the color of the white LED light. The lights I bought did not specify CRI, only color temperature, but in any case they were a huge improvement over the horrible greenish hue of the CFLs.

BitHead77
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Silicon substrate
BitHead77   3/20/2014 6:47:23 PM
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Wouldn't the use of a silicon substrate also allow some of the drive electronics to be built along side the LED(s) that is(are) being driven?  Could this be used to reduce cost as well?

baybal
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Re: Silicon substrate
baybal   3/21/2014 4:15:11 PM
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No,

Why? It is impossible to put an efficient capacitor or inductor on silicon yet. It is possible however to put other non-conversion related components like dimming.

Even if somebody will manage to make a self-driving chip with high step-down, it will be inefficient in comparison to dedicated driver.

In addition to that, most of led products nowadays are using LEDs in multi-chip modules, in which a lot of cheap blue leds are bundled instead of single, high current one.

_hm
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The Best Light Source?
_hm   3/22/2014 6:53:00 AM
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"and a versatility in the spectrum and character of light beyond that offered by any other source that humans have yet discovered or invented."

Really? CRI for LEDs are pretty poor 95 or 96 at best. How do justify this?

DrFPGA
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Great summary and lots more info at
DrFPGA   3/23/2014 6:11:19 PM
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http://www.allledlighting.com 

If you are interested in what's going on in the world of LED Lighting follow Keith and his trusty minions at www.allledlighting.com for some the the most illuminating discussions on the good, bad and ugly in the LED lighting market.

You will be amazed at the brain power that explodes daily from the site... Really!

LarryM99
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Re: Great summary and lots more info at
LarryM99   3/23/2014 7:49:21 PM
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You are right, it is an interesting site. I knew that there had to be somewhere where they were pushing the limits and doing interesting things with LEDs, and this is a good example of that. Thanks much for the reference!

AZskibum
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Re: Great summary and lots more info at
AZskibum   3/23/2014 11:01:26 PM
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"most illuminating discussions", LOL! Thanks DrFPGA, I will check it out.



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