I've got both the CostCo LED F40T12 replacements and the dedicated costco 48" LED fixture. They both work well so far (the T12 replacements are in a former fluorescent fixture in the attic, and the dedicated fixture is over the workbench in the shop (augmenting 4x2xF96T12 C50's).
The color temp for the dedicated fixture isn't 5000k, but it's not too far off.
Tahw?
Hold it in front of an upside down mirror.
I Haven't seen that one in a while, but alas, 'tis still true.
LOL. I probably should have remarked, ?tahW
?huh
There is no mercy on the wreck!
It is these phosphor mixes that are driving the LED lighting market. Very difficult and proprietary tech. Need a great UV light source? Get one of those Phillips bulbs with the phosphor coating on the bulb envelope and remove that envelop. All the creepy crawlies like scorpions will glow brightly in you garage/shop at night....
-BR
LEDs are one of those products where quality varies widely and usually is in no way related to price. You can always crack one open to determine quality, but the easiest way is to heed reliable reviews and look for a good warranty.
-BR
An old rule for electronics is 10 sq. inches of heat sink surface (exposed to room temp) for every Watt of power. Many of the "flood" style bulbs which don't have the room for this get by with thermal mass. They don't saturate the heat sink for 1-2 hours, giving you time to get your lighting task complete before damage begins. This is the bane of the Edison style bulb for LEDs. Tubes have the surface area going for them, but the cheaper tubes find a way to skimp on the aluminum to mitigate any advantages 8^)
-BR
There seems to be a lot of confusion concerning LED's and their heat out put. I have LED lamps that replaced incandescence bulbs and the light is cool but the part that converts to the proper voltage generates heat.
I also have probably 20' of high density ribbon LED lights that run on
12 volt and they do not even get warm.
Just hung the first one. Instant on, no buzz, no flicker. Plastic housing , but I guess that's OK. Light seems a little "warmer" than the strong whi te I got with the fluorescent. I'll be curious to see if they last 45 year s, but by then I'll be 115 and probably won't remember to check. :-)
For $30, I judge this to be a good deal.
You can bet that the semiconductor junctions are getting warm. The fact that the surface isn't may also mean that the semiconductors inside are getting downright toasty. My thermos mug doesn't get warm on the outside, even when filled with very hot coffee.
I agree with it being a good deal - even better when I paid, IIRC, $26 $28 each for mine.
Out where mine are hanging in the garage, I don't notice the color temp that much (though I prefer warmer) but you surely will notice the instant full output if you put them in a cold area like I have.
How do it know?
Simple - I used to design and test semiconductor material - I started in the mid 70's and went pro in 1980.
I remember some of the first high speed CMOS HMOS and NMOS that ran really fast but shorted power to ground in the output transistors in the process. It seemed ok in theory - but after millions of cycles the part melted the epoxy off the IC !
All semiconductor heats up. It is conducting current. Current flow causes vibration heating.
Mart> >> >>
But in actual tests is that the major failure mode of commercial LED lighting?
Well, it's not a Crapsman. ;-)
Commercial or residential? I know it's the failure mechanism in residential LED lighting. Commercial may be better. Or not.
I cab pinch the ribbon LED beteen my thumb and my finger. Nothing. We leace these lamps on in our kitchen 24/7 and there is not heat what so ever.
But you can't touch the junction, which is what counts.
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