On 5/5/2011 10:41 AM, Jim Yanik wrote:
wrote in news:ipu43o$g07$1@dont-
email.me:
On 5/4/2011 11:48 PM, hr(bob) wrote:
On May 4, 6:50 pm, wrote:
On 5/4/2011 3:55 PM, Larry Fishel wrote:
On May 4, 2:30 pm, wrote:
Googled this up at HD:
http://tinyurl.com/4xx897u
Interesting that the stated power consumption for this bulb is
actually HIGHER that for a 40W equivalent CFL...
A lot of light being wasted in a filter to improve the color?
I was wondering about that but had not looked up the comparison.
I don't know a lot about electronics but do know that LED's need direct
current so part of the extra energy may be in the AC/DC conversion.
I would worry about the color too. I had bought a couple of CFL's that
put out such white light that I could not use them indoors and had to
consign them to the front porch.
CFL lamps also require dc, they rectify the AC powerline ti dc, and
then run a high-frequency dc - ac converter tolight the lamp tube
itself. There is a large step-up in voltage needed to strike the
initial arc thru the tube, and the reduction in mercury reduces trhe
pressure in the tube until it heats up a little. Regular tubular
fluorescents contain appreciably more mercury than the cfl's do
because the arc lengthis mujch longer and the diameter of the tube is
much larger.
Did not know that. I do recall someone posting a diagram or picture of
internal electronics for a cfl and there was a lot of stuff in there.
Surprising that they can make them so cheap.
mercury is what provides the initial ions for current to flow across the
tube. it helps establish the arc.
I took apart a CFL and it only had two transistors,a tiny transformer,a
couple of electrolytic caps,2 diodes and some chip caps. It rectifies and
DOUBLES the input voltage,then converts to HF AC.
Next time one of mine burns out, I'll take it apart. The diagram I saw
looked complex for a light bulb. Sounds like what Wiki says:
Electronic ballasts contain a small circuit board with rectifiers, a
filter capacitor and usually two switching transistors connected as a
high-frequency resonant series DC to AC inverter. The resulting high
frequency, around 40 kHz or higher, is applied to the lamp tube.
Also noted of late, cfl's I've bought have been little hummers. Can't
recall in early ones. Maybe it's the cheap Walmart stuff I bought.