White light bulbs give off yellow light?
something that I have noticed is that the lights that I have in my house have a yellow tint to it, but the light bulbs are white. So if I wanted light that actually looked like a bright white light instead of a yellow/orange looking light, what kind of light bulb should I get?
Why do new LED house light bulbs burn out so quickly in comparison to older house lighting types?
Lots of good answers. They all come down to one of the following . . Temperature (usually due to lack of ventillation - but operating near an old-fashioned tungsten bulb can also be pretty lethal . . Poor design or workmanship . . Incompatibility with local electricity supply (ignorance or wilful mis-selling?) . . Contact issues - most common where the contact was previously to a tungsten bulb; the destruction here is not usually due to general overheating, but the sparking can be equivalent to turning the bulb on and off many times a second, and the ciruitry is simply not designed for this . . Incompatibility with the particular dimmers being usedPeraonal experience: the lighing in my basement flat was grim, and my wife and I both work from home, so it was lit between about 7am and 11pm. We had maybe thirty lamps altogether, half of them MR16s; this meant a lamp failed about every five days on average. We require good colour rendering, which meant we were only able to move to LEDs a couple of years ago. We now have over have 100 lamps, most of them GU10 spots in the ceiling, and nearly all of them are on compatibe dimmers*. These are housed in fire-rated enclosures, so the air-cooling is perhaps not the greatest. There is a power penalty associated with the best colour quality: the ceiling lamps are all rated at 5.5W. Nevertheless, just five of these lamps have failed, most of them quite early on**; this compares with about 300 hundred replacements that would have been needed in the time had we been able to use this number of halogens***.So, based on personal experience: good quality LEDs can last if you give them the opportunity!*We tried several brands of 12V LEDs, but none of them were compatible with our transformers (another hazard?); in the end t was simplest to change the fittings to GU10s. **Theoretically we could return these to the supplier, but it is simply not worth the hassle. ***This would have been 6-kW extra heat - OK in winter I suppose, but also prohibitively expensive where I live.
Why do my LED bulbs burn out?
The most likely cause is heat. They don’t like high temperatures.Yes, its true that incandescents they replace made a lot more heat. A 100W incandescent is replaced by a 10W LED. There’s 90W more heat generated by the old bulb.But, the old bulbs were meant to run hot. The filament temperature was where the heat was, it glowed with 3200 degree heat! Yes, 3200 or thereabouts. The heat was at the filament, and even through the glass burned your hand it was greatly reduced by the low thermal conductance of the filament supports.The sockets were ceramic and meant to take the heat that was left.Your new LED bulb is quite different. While its super efficient compared to the old bulb, it is not totally efficient in turning electrons into light. some of the power goes into converting the high voltage AC into low voltage DC required by the LED. The LED produces heat. The waste heat from this is all dissipated in the small neck of the bulb just above the socket. A 9W LED bulb will produce almost that much heat, 9W.It generates so much heat in a small space that many of the bulbs you buy have metal heat sinks in this area to help get the heat out.When placed in a small volume it can raise the temperature of the trapped air quite a bit. While temperatures of 250 F didn’t faze the old glass and metal bulbs, the temperatures of maybe 175 F are really tough on electronics. The electronic chips and capacitors often run much hotter internally than tha air around them. In short, a LED bulb in an isolated, closed space will get hot and fail early - a year maybe. Nothing like these 50,000 hours they claim!The makers vary greatly in the amount of heat sinking they provide and no one can provide enough for a tightly sealed space.Make some ventilation if you can!
If you had a light bulb on the Moon connected to a switch in your bedroom, how long after the switch was turned on would it take for the bulb to light up?
I'm neither a physicist nor an engineer but I will try to answer this question. Any physicist/engineer who knows the answer should correct me since I, myself, would like to know the actual answer.The speed at which electric energy or signal travels along a cable (e.g. copper wire) is actually the speed of electromagnetic wave propagation, not the speed of electric current (electron drift speed). Electromagnetic wave propagation is fast and depends on the dielectric constant ϵ of the material. In a vacuum the wave travels at the speed of light and almost that fast in air. As the moon is about 400,000 km from the Earth and the speed of light is about 300,000 km/s, the time it takes for electromagnetic waves to propagate from the earth to the moon is about 1.3 seconds but only if the waves travel in vacuum. For a copper wire conductor with a relative dielectric constant (ϵ/ϵ0) of 3, the speed will be 58% (I will round it up to 50%) of the speed in vacuum. Another factor that will affect signal propagation is magnetic susceptibility μ, but we can make it simple by assuming that the copper wire + filler material is "magnetically neutral" (μ=0). This is actually not bad at all because it is actually close to 0. Another simplification is to disregard the time it took for the signal to travel from the power generator or electric plant to your house. With all these simplifications in mind, the answer is 2.6 seconds. It takes 2.6 seconds after you "close the circuit" for the bulb to light up on the moon. If you are asking how long it will take for a person on earth to know that the bulb is lit after switching it on, you must add the time it will take the signal to return to earth by traveling in the vacuum of space: 2.6 seconds + 1.3 seconds = 3.9 seconds or about 4 seconds.Addendum: Resistance was ignored in the above discussion. Because of the very long copper wire needed to conduct the electric field from the earth to the moon, you must provide voltage (electric energy) that is much larger than the usual 110V or 220V you can get from your wall outlet. If not, all the electric energy will be dissipated by resistance (converted from potential energy to heat) even before it gets to the moon to effectively drive the current inside the bulb filament. How much voltage? Well, that would be another good Quora question.
What is your opinion of LED lights in your home rather than incandescent?
This is for the US.Up to 80 % energy savings.Up to 25,000 hour life for LED vs. 1,000 hour for incandescent.A wide range of Kelvins (2700K to 3000K is equal to incandescent)Most residential fixtures have an LED replacement for incandescent. Heat is a concern with LED lamps because of the electronic circuity. I recommend replacing fluorescent fixtures with a newer design fixture using LED or LED compatible.The color red is low in some LED bulbs. Look for 90+ CRI. Look for the GE Reveal brand.Check dimmer compatibility with LED. Bulb and fixture manufacturers have compatible dimmers listed on their web pages.LED lamps and fixtures allow for a wide range of lighting techniques not easily provided by incandescent - wall washing, wall grazing, toe kick floor lighting, cove lighting, handrail lighting, directional light, decorative light, colored light, color changing, and circadian rhythm lighting to mimic the cycle of daylight.Check with Chris or Isabelle at Illuminee lighting in Santa Cruz should you have additional questions. Look at the Nendo desk lamp, the Louis Poulsen fixtures, the Pablo Designs Pixo lamp, and the store displays.