On 01/05/2015 12:15 PM, bob wrote:
On 1/2/2015 8:56 AM, Arfa Daily wrote:
EE Times article that came to me by email today

http://www.electronics-eetimes.com/e...s_id=222923405



Arfa
Well, i can totally see that. Part of the reason is NOT the LED's
themselves, but the CAP's. If there is a modern multinational cartel
these days, its NOT oil but the manufacturer of small capacitors. They
build these dam things to fail in a few years anymore. Between the
elevated temps they operate at and lack of quality guts, capacitors are
the weak link. And that includes LED lights because they use them in the
power supplys.

Last year, i bought a bargain CFL lamp for $1 at the dollar store.
Worked for maybe a hour them ZBOOOM! TOOK it apart and sure enough,
capacitor guts all over.

It seems most modern LCD tv's have a life of two or three years then
they go haywire. I was all ready to get a new Sharp LED set before the
first of the year on sale and was about the push go, then figured
i better do some research first. Pages and pages of it failed soon
and the manufacturer would not help. I'm sure capacitors are one
of the major reasons for that also.

i just saw some 40W LED bulbs at a ACE US hardware store for $5.99 on
sale. almost got one, but held off for now. Its hard to beat the
simplicity of a incandescent lamp.

bob

As usual, heat is the enemy. Reading the technical specs for caps is
enlightening. They are rated usually at something like 2,000 to 5,000
hours at their rated temperature. So an 80C cap will die after something
like 2000 hrs at 80C or 4000 hours at 50C and 10000 hours at 40C (not
looking it up!), whereas a 105C cap will last 10000 hours at 85C, etc.
So, the better the grade of cap the longer it will last in warm to hot
environments. And there is the equivalent resistance and inductance to
consider as well. Some caps are much more tolerant of 50/60hz and others
are better at 20,000hz. Selecting those takes time and the cost
accountants slip in at some point...

John :-#)#

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