I grok!
It all comes down to the power consumed by the devices. 60 Watts of power has to go somewhere, some into actual photons (light), the rest into heat. This heat, as far as the LED, an be considered a point source. Some gets radiated away, the rest gets moved into the surrounding heat sink *or any other contacting material that conducts heat).
-BR
Yep, 48 Watts over 600 LEDs and usually a small resistor for each 3 LEDs (in series) to knock down the current. These 3528 LEDs have typical forward voltages of about 3.4 Volts. Three in series (10.2 Volts) means the resistors dump about 15% of the power as heat (These usually are driven with a 12 Volt supply).
As far as efficiency, the 3528s are near 100 Lumens per Watt which is very good, they produce light more efficiently than others (the color index is rather lousy though).
I usually purchase the parts separately, the LED strip can be had for $10
and a 12 volt laptop computer power supply for less than that.
Requires a bit of assembly, but perfect for when I make built-in lighting for a project.
-BR
;~) I'm just saying that some LED's can remain on 24/7 and not be even warm to the touch, others will burn you after a few hours.
I have them as under cabinet lights too, they are excellent!
Spreading out the light is what they excel at. Lee Valley (and others) sell housings for them that provide a great way to mount them and have diffusers in clear, translucent and an "opal". The diffuser makes them look like a continuous bar of light instead of many little dots, important if you have shiny counters (though they do cut the light output quiet a bit).
-BR
60 watts is an effing HUGE consumer LED light bulb though.
The flourescent tube replacements are typically
17 watts for a four foot tube and a replacement for a 100 watt incandescent typically draws 14. 60 watts would have light output in the same ballpark as a 400 watt incandescent--this is way outside the typical "consumer" range.
Are some LED's designed to run on 120 volt? I know about the LED lamps that screw directly into a 120 volt socket, I was under the impression that the voltage was converted to 12 volt and the heat was generated from that conversion since the bulb does not get hot so much as the electronics.
In this last case, the ribbon kit referenced above, the LED's put out a day light color That was important to my wife as she wanted no color added when looking at the material on a quilt. But fortunately unless looking straight into the LED's they appear to be a little yellow and dim. This is good to prevent seeing spots after looking at the string of LED's.
I saw a lot of options but this kit had all the connectors, dimmer switch and remote, power supply for $50. I was good with that especially since I did not have to worry about compatibility.
I thought about the diffuses, but opted for sticking directly to the bottoms of the upper cabinets. We have shiny granite counter tops you you do see each individual LED in the reflection but is is not distracting and It seems you have to be in just the right position to notice the spots on the counter top. Any thing 3' out and you don't see them at all. Closer you see them but they are simply spots that do not distract.
Hot water can burn you, too. As long as it's in the thermos, you're safe, though. If you put it in a Styrofoam cup and stick it between your legs, while driving, bad things are more likely to happen. ;-)
That doesn't mean both coffees aren't hot.
BUT the thermos has a giant separation between the coffee and your hand. With ribbon LED's you can directly touch the circuitry and LED's that are attached to the ribbon.
Front to back the LED ribbon is about 3/32" thick that includes the adhesive backing, ribbon, printed circuit and the LED. There is nothing keeping you from touching any of those components. LED ribbon is not totally unlike a printed circuit board except it and the components are much thinner and very flexible.
The numerous paired gold contacts are about 1" apart, that is where you cut to length with scissors to attach a pigtail for power.
Sorry, you missed (or never heard) the joke.
There are a number of variations. The safest one is...
A teacher was telling her class about the greatest invention ever: The Thermos Bottle. "It keeps cold stuff cold and hot stuff hot".
One perplexed student asked her: "How do it know?"
The best ones have a FET in series that acts as a current driver and delivers the proper value. No resistors - FET and Diode on the tiny chip. Supply voltage varies and has a useful range - LEDs (Diodes) are in parallel since the FET is in series with it. The driver then dumps and maintains say 4-5v and all regulate and shine. One goes out and the rest are on.
That is the best way but not the cheap way.
Mart> >>> >>>>
No, you're not. There is a big hunk of plastic, or three, between your finger and the active bits.
I'm sure it is a printed circuit (AKA "flex circuit"). That doesn't change the fact that you're *not* touching the LED junction itself.
\\
Sorry, I was thinking incandescent equivalent when I was intending the LED equivalent.
-BR
Early LED lamps had a series of standard "gum-drop" style LEDs strung such that the voltage across each LED was within spec when run directly* from 120VAC
The first versions had horrible 120 cycle flicker, later versions added a capacitor to help out. LED Christmas lights were also this way.
LEDs need a constant current source. If fed from a constant voltage source, small variations in voltage and temperature can produce visible changes in light output. Most, if not all LED bulbs run from an internal constant current AC to DC convertor. The LED strips need the small resistor so they can work with a "standard" 12VDC supply, but they will (and do) vary in brightness. Most 12VDC supplies are regulated well enough to avoid noticeable light variations (flicker), but the temperature variations are still there, just very gradual.
Yes! From a man who has a Domino, I understand 8^) You wanted a turn-key setup, not a chunk of steel you need to turn into a chisel so you can chop a mortice. I like saving a few $$ so I can spend a few extra hours searching for my spool of solder and ordering new tips for my soldering iron. It's the way I roll 8^)
-BR
-BR
I doubt it is even close to the most annoying thing in e-mail.
As others already replied, duty cycle is a major factor. The business ones are usually on all day. Home units are cycled many times a day, and starting a flurorescent lamp is stressful on the lamp.
I have the opposite experience. I got an electronic ballast for a homebrew bedroom lamp using a Philips PLL tube (thin "U" shape). The lamp's lasted for many years with no visible weakening. Instant on, no flicker to the eye or on my camera, and it seems gentler to the tube than magnetic ballasts. And it's silent.
-- jeffj
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