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Electrolytic and Tantalum Capacitor Life?

B

Bill Bowden

Jan 1, 1970
0
Capacitor specs seem a little confusing about expected lifetimes. It
seems to depend on various factors of temperature, current, frequency,
etc.

Just as a general rule, how many continuous hours of operation would
you expect from a electrolytic or tantalum capacitor assuming the
charge/discharge cycle is fairly long at maybe 1 cycle per second?

Which will live longer, Electrolytic or Tantalum, and does packaging
make much difference (SMD verses axial leads)?

-Bill
 
P

Phil Allison

Jan 1, 1970
0
"John Larkin"
Aluminum electrolytics slowly lose water through the seals and
eventually lose capacitance, very roughly half in 20 years? Depends on
the construction quality. High temperature accelerates the dryout.

** Aluminium electros are made with excess electrolyte inside - to allow
for evaporation loss over lifetime. The first sign that loss has reached the
limit is the ESR (or internal impedance) begins to rise. Not until the ESR
has risen by a large factor, maybe 10 to 100 times, will the actual
capacitance value drop.

This is the reason service techs always use ESR meters to test electros,
rather than capacitance bridges.

Also, I have seen many electros that have good ESR readings and full
capacitance when they are 50 years old.



..... Phil
 
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