zivotnost kondiku

Draček Fráček dracek.fracek na gmail.com
Pondělí Březen 7 17:49:33 CET 2011


Toto je bezne uvadeny vztah, zakladem je
http://en.wikipedia.org/wiki/Arrhenius_equation, pak je to o
statistice.
Elektoliticky C je podle meho nejproblematictejsi soucastka dnesni
elektroniky. Popravde si jiz ani nemamatuji, kdy jsem neco opravoval z
jineho duvodu nez vyschly elit. A aby toho nebylo malo, beznym
miltimetrem se to tezko pozna :-)

Martin



2011/3/7 David Obdrzalek <David.Obdrzalek na mff.cuni.cz>:
> Narazil jsem na zpravicku v Q/A u Farnellu, prodavam jak jsem koupil:
>
> Q: I notice that a lot of aluminium electrolytic has stated life times that can be
> as low as 2000 hours. Does this mean that a product that is in use for 40 hours a
> week would only last a year?
>
> A: This is true but this figure is at the max working voltage and at the max
> ambient temperature of the capacitor. Fortunately, by reducing the working voltage
> and/or the ambient temperature of the capacitor, the life of the capacitor
> increases dramatically. The bigges factor of the two is the ambient temperature.
> The following equation shows that where voltage has a proportional effect,
> temperature has an exponential effect:
>
> Lfinal = Lr * ( Vr / Vw ) * 2^Th
>
> where Th = (Tr - Ta + Dt) / 10
> Lr = Rated life of the capacitor
> Vr = Rated voltage of the capacitor
> Vw = Working voltage of the capacitor
> Tr = Rated temperature of the capacitor
> Ta = Ambient temperature
> Dt = Temperature increase due to the ripple current which is the hard part to
> establish but can be measured.
>
> Taking an example of a 63V, 105°C capacitor with a life of 2000 hours, we can
> extend the life to over 142,000 hours if we have a working voltage of 40V and a
> temperature of 50°C, a 70 fold increase.
>
>
> Zdroj ovsem nerika, jak k tomu vzorecku prisel. Je mozne, ze by to bylo az tak
> jednoduche (a silne)?
>
>
>
> Zdravi
>
> David Obdrzalek
>
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