On Fri, 2 Jan 2015 14:56:48 -0000, "Arfa Daily"
wrote:
EE Times article that came to me by email today
http://www.electronics-eetimes.com/e...s_id=222923405
Arfa
What the article says is that if you calculate the MTBF of an LED
light, it will be lousy. That's true, except that it's no longer
important because such lights are designed to fail. Conspiracy theory
follows.
The problem with LED lights is that they can theoretically last
forever. All that's required is some really good heat sinking, decent
components, and AC line glitch protection. You might see those on
tower lights, runway lights, and other high reliability applications,
but not on the consumer stuff, unless the GUM (great unwashed masses)
suddenly decide that paying for quality is a good thing.
The reason for the designed in failures is the need for manufactories
to continue selling replacements. If they actually made a device that
lasts forever, they will sell a few years worth, and then go out of
business because there will be no replacement sales. Reliability is
bad for (consumer) business.
There's another problem. Anything that lasts longer than the intended
product life is considered a waste of money. For commodity items like
lighting, every penny is important because when selling millions of
lamps, the pennies add up quickly. The result is that failures are
evaluated on basis of MINIMIZING their lifetime. If something lasts
twice as long as originally intended, it is considered a candidate for
"cost reduction" which by implication means "lifetime reduction".
Ideally, the result is a product where everything fails simultaneously
one day after the warranty period. We're fairly close to the idea in
the consumer electronics and computah industry. I've seen such
simultaneous failures on the bench, especially old Sony CRT displays,
which showed evidence of intentional electrolytic capacitor lifetime
manipulation (weird voltage rating on the caps). With today's heavily
computerized design and modeling tools, it is possible to design for a
specific lifetime.
All this begs the question "Why did the author write the article"?
Scott Elder is no slouch and works for a reputable manufacturer of the
chips used to run LED lighting. Presumably, he knows how it all works
and has real data to substantiate his allegations. It seems counter
productive that an industry insider would write an article denouncing
the industry perception of LED lifetimes and reliability. My best
guess(tm) is that he's frustrated by the aforementioned penny counting
cost and lifetime reductions and wanted an indirect way to point out
the problem without appears to be a conspiratorial wacko like me.
That also begs the question "Why did Arfa Daily post the article"? My
best guess(tm) here is that he's still having problems adjusting to
LED lighting and needs a new reason to not use LED lighting. Am I at
least close?
This also begs the question "Why did I write this long rant when I
should be doing something productive"? That's easy. I like to write
conspiracy theories. It's also Friday evening, which I reserve for
working on my own projects. Finally, I've had some medical problems
lately and feel lousy enough to want to dump my problems on the world.
This is a good start.
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558