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The capacitor plague
Robert Orban (of Optimod fame) used to say, semi-seriously, that
“you can’t trust the green ones”. They’re in everything electronic
and their premature failure may be gradually bringing the consumer
electronics industry to its knees all around us. Why is it that we apparently
have lost the ability to make a decent, reliable electrolytic
capacitor?
This is a high-tech horror story: of industrial espionage gone wrong,
of technology without borders and of the growing interdependency of
all things. It is a case of truth being stranger than fiction. And it is a
story that, although it started in the mid 1990s, continues to unfold to
this day.
There’s a reason that all our electronic products seem to work fine
right after we plug them in, but start to misbehave somewhere between
six months use and the end of warranty. Whether we’re talking about
a computer motherboard, a DVD player or a TV set, there’s a bunch of
electrolytic capacitors inside, and some of them are likely literally boiling
away with every use.
“Electrolytics” have been with us since the dawn of electronics.
There’s been increasing pressure to make them smaller, with lower ESRs
(equivalent series resistance) and higher performance, and to make them
in a surface-mount form factor. All of these developments have required
extensive research and development, and where there’s money being
spent on R&D there’s also, apparently, industrial theft.
A Japanese capacitor company developed a superior electrolyte recipe
in the early 1990s. One of their scientists left and joined a Taiwanese
capacitor company where he duplicated the first company’s secret recipe.
A few colleagues at this second company then departed and started
working for a third company where they successfully reproduced most
of the stolen recipe. But some critical components were missing … some
chemicals that would prevent the resultant capacitors from breaking
down and blowing up after a short period of use.
ENG
INE
ERI
NG
by Dan Roach
What Happens?
The electrolyte inside these capacitors is a corrosive aqueous solution.
The missing chemicals were put in there to keep the electrolyte
from breaking down in the presence of electric charge. Lacking them, the
paste inside our defective caps does just that, releasing hydrogen gas.
bRoADCASt DIALoGuE Technology Insider • June 14, 2011 18