What type of lighting is safest for a high-heat application?
Question by Kelsey: What type of lighting is safest for a high-heat application? Trying to install accent lighting under a fireplace mantle, which obviously gets hot when there’s a fire. Halogen bulbs are a no-no – killed the bulbs after 2 hours the first time the fireplace was on. Will LED bulbs be safe in this application? If so, should I purchase a pre-integrated puck, or a fixture for MR16 or Gu10 lights? And which of those two options would be safer. MR16 means the transformer would be elsewhere, but it’d end up inside the wall or directly behind the plasma TV, so I’m not sure that’s any better – Gu10s would have the transformer right at the light, but can they handle the light?
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Could someone help me out with Lux/Lumens levels.?
Question by : Could someone help me out with Lux/Lumens levels.? We would like to compare different light globes in lumens and lux. So I’m trying to convert Watts to Lumens and Lux. PLease HELP. 100w Incandescent globe = ? lumens and ? lux 20w ES Compact Fluro globe = ? Lumens and ? Lux 36w Linear Fluro Tube = ? lumens and ?lux 13w GU10 Compact Fluro = ? Lumens and ? Lux 5w LED = ? Lumens and ? Lux 50w GU10 Halogen = ? Lumens and ? Lux 50w MR16 Halogen = ? Lumens and ? Lux Or any websites for dummies on converting watts to lux/lumens.You could direct us to would be great. Or is there a formula to do this?? if there just easy converter web site to use to help me maybe that we easier to get my answers.
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How many white LEDs in series on 120v AC?
Question by Kevin D: How many white LEDs in series on 120v AC? OK folks, I don’t think my actual question is quite as straight forward as it seems here, but maybe someone here can help anyway. I bought a GU10 48 LED bulb (think track lighting) made to run directly off ~120v AC. After a few months of use (around 100 total usage hours), it failed due to an LED burning out. So, being the inquisitive person that I am, I had to open it up to see how it ticked.
Basically, the simple circuit driving the LEDs contains a couple capacitors, a few resistors, and a full-wave bridge rectifier:
x | C1, C2, R2 (all in parallel) | —-| D — D |ssss| (-)o ———- R3 –o (+) |ssss| D — D —-| | R1 | x
The 120v line voltage is applied at the “x” and the circuit output is the “o” (the ssss is a space….it’s difficult to draw a circuit here). For whatever it’s worth,
R1: Resistor bands are too difficult to read (and I don’t have a multimeter handy), but I think it was around 500 ohm R2: Surface-mounted resistor; 150 stamped on it (assuming 150 ohm) R3: Surface-mounted resistor; 150 stamped on it (assuming 150 ohm) C1: 250v 474J capacitor (unsure of capacitance) C2: 250v 684J capacitor (unsure of capacitance) D: M7 diodes (rectifier bridge)
When I measured the RMS voltage at the circuit output, it was 110v (vs. 120v input). The 48 LEDs are wired in two series of 24 LEDs each (only one string was non-functional). Doing the math tells me that the LEDs are being driven at just over 4.5 volts, which seems exceedingly high (assuming a forward voltage of ~3.5v for each one normally). So, this brings me to my question….I wondered how many more LEDs I could string in a single series off this circuit configuration without going past 3.5v. Again, doing the math would lead me to believe that I could add maybe 10 more LEDs to the series and be OK. But, in experimenting with it, I was able to add a bunch more than that without any discernible decrease in light output. I think I stopped trying at around 25 extra LEDs in series with the original 24. What gives? I realize LEDs are current driven devices, but they would still need a certain forward voltage to operate, right?
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Has anyone tried LED Lightbulbs?
Question by Robert W: Has anyone tried LED Lightbulbs? I have several fixtures that use the GU-10 bulbs (like in this picture http://www.febri.pl/img/GU10-50.jpg ). As I understand it, LEDs are very ‘directional’ and not especially good for regular fixtures, but what about in ones that are meant to be directional? In any case, if anyone has an opinion on these, I’d appreciate it.
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GU10 lights and light-fittings?
Question by : GU10 lights and light-fittings? Do you have GU10 lights/lightbulbs in your home/house or office? Are they good? Are they LED or halogen or neither of these! All answers will be helpful to me & thanks in advance!
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