LED Lightbulb
LED Lightbulb
(OP)
How does a LED lightblub that screws into a standard lightbulb socket work? Is there a brige rectifier that changes the 120VAC to some DC voltage and then the LED's are connected in series for an appropriate voltage drop?
Following Link is an example of the product I am discussing
http://www.ccrane.com/lights/led-light-bulbs/index.aspx
Any help is appreciated
-Joe
Following Link is an example of the product I am discussing
http://www.ccrane.com/lights/led-light-bulbs/index.aspx
Any help is appreciated
-Joe





RE: LED Lightbulb
Dan - Owner

http://www.Hi-TecDesigns.com
RE: LED Lightbulb
It is just as stated.
Rectified AC fed directly to 62 LEDs in series if memory serves.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: LED Lightbulb
Didn't the human race learn anything from the misery of those old-fashioned series-connected Christmas tree lights?
RE: LED Lightbulb
RE: LED Lightbulb
The only way these LEDs will ever become a mass market item is when they're made in China and do not cost $350 each.
Based on reviews I've seen on websites selling early-generation LED lightbulbs (made in China), the failure rate is not yet acceptable. I'm as early an adopter as anyone, but I'm not buying LED lightbulbs for my house just yet.
RE: LED Lightbulb
But as that was bleedin edge stuff the link the OP put up has some MUCH less expensive units that I suspect are XXXXX times brighter.
You can go either way. An SMPS or rectifiers. I'm sure the rectifiers are far cheaper and possibly more robust due to far lower parts count but they may not be as bright due to lots of ripple. (hic)
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: LED Lightbulb
I used to test LED lighting products at work and the problem is, as you say, that they are too dim...or rather, they are bright but only in the "zenith" direction.......to get them spraying light around more you end up having to use too opaque diffusers.
I once switched a nine Watt LED light on with no diffuser(contained about 80 LEDs) whilst holding it about a yard in front of my face.....it was painful and i never did it again! - i can stil see the flash in my mind's eye.
To get round the problem of blowing one LED in a long series chain..........put suitable value zeners across series lengths. -current can then divert via the zener if one blows.
Of course, the beauty of LED lighting is precisely that it is dim, -and can provide nice "mood" lighting if done right. Also, as you know they can be switched on/off in colourful patterns.
RE: LED Lightbulb
Dan - Owner

http://www.Hi-TecDesigns.com
RE: LED Lightbulb
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: LED Lightbulb
The idea of putting zeners across series sections of LEDs was shown to me by the Senior Electronic Engineer at a fairly large lighting company. (-they make warning beacons etc). This was at an interview. He asked me what the zeners were for and i said to stabilise voltage....he then replied "no"...but that the zeners were to keep the remaining LEDs lit if one blew. .....it was a long series chain of LEDs.....and every series length of some 10 LEDs had a zener across it.
RE: LED Lightbulb
In the most recent case you mention, each smaller string has a significantly smaller power requirement, so if a string goes open the corresponding zener takes up the load... but it's a much smaller load, and therefore is reasonable to assume it will continue to operate.
Dan - Owner

http://www.Hi-TecDesigns.com