On Thu, 20 Jan 2011 13:03:39 -0700, "WW" wrote:


"Frank" wrote in message
...
On 1/20/2011 12:42 PM, Smitty Two wrote:
In article
,
Molly wrote:

http://online.wsj.com/article/SB1000...595565026.html

I'm siding with other soothsayers predicting an LED revolution. The
latest issue of Digi-Key's "Tech Zone" trade journal is devoted to LED
lights. Colors are getting much better, the elusive triac dimming puzzle
has been solved, etc.

LED's require a set directional DC voltage. I think that's going to be
the big price drawback. Great for flashlights with batteries but $100 LED
bulb with built in AC to DC converter is not worth it.

Don't need one. LEDs ARE AC to DC converters. The problem is dimming them
cheaply.

I build my own LED night lights to illuminate our halls and bath rooms for
rising during the night. Plug into wall outlets. A diode in series changes
the AC to 1/2 wave DC. Leave them on 24 hours a day. Works great. WW

LEDs *ARE* diodes. Another diode in series does nothing except waste power. A
diode bridge around them, making it full-wave DC, is a good idea, however.