Looking for lifetime 5,000 hours of electrolytic capacitor.

I wasn't aware that electrolytic capacitors fail after 6.84 months. Sheesh, better warm up the soldering iron.

nichicon's slightly-gobbled-English statement: "After an application of D.C. bias voltage plus the rated ripple current for stated in the below at 105°C the peak voltage shall not exceed the rated D.C. voltage, capacitors shall meet the following requirements. Capacitance change within ± 25% of initial value, tan d 200% or less of initial specified value, Leakage current lnitial specified value or less."

So, the answer is, stay well below the capacitor's maximum rated D.C. bias voltage and ripple current, and stay below 105°C. What's so hard about that?

BTW, nichicon's HE series (the one I happened to look at) is spec'd for 7000 hours for its 8mm case size.

Temperature is 105 degree.

That's a relatively long rated life, of course.

Best regards, Spehro Pefhany

at what temperature?

martin

thats:

martin

Life is affected by operating temp and ripple current. Derating provides more life.

So. What's the ambient temp for your cap for starters ?

Graham

I guess that's about as minimalist an answer as can be achieved ! Do you actually *want* some assistance or are just trying to be bloody awkward ?

Do you mean you want a 105C rated part or the actual environment is @

Big big difference in the outcome.

Graham

Well, lessee - a 32768Hz watch crystal, a bunch of counters to time 5000 hours, at which time, apply appropriate reverse voltage and blow up the cap?

Good Luck! Rich

might work, if the xtal osc doesnt use caps

martin

On 23 Sep 2005 16:14:54 -0700, "Bob J." etched in cyberspace:

I'd say steer clear of electrolytic capacitor and choose another kind that can stand high temeperature. The average plastic capcitor would not do to well at 105 C either. X X X X X

Hi, pooh Bear,

Thanks,

Hello Winfield,

Yep. I have a few radios from the late 40's early 50's. The electrolytics in these seem to be doing just fine. One younger example: Grampa's Philips Gemma, ran five hours every day for 20 years except on Sundays. That's about 280 days a year considering vacations etc. So let's see.

Then the AF transformer went and they bought a transistor set. Yech. I repaired it and since then it clocked at least 2000 more hours. The electrolytic in there runs a little above 80% rated voltage and gets quite hot because of the tubes. Yet it never flinched. IIRC it's on its first set of tubes, too.

Regards, Joerg

I don't know what country code you're isunging but I'm afraid I can't read what you posted properly.

It's important to know the actual operating temperature *in any case / enclosure *.

If you're using a 105C part then double the published life figure for ever 10C cooler that it runs.

E.g.a 2000 hr 105C part would be good for 16000 hrs @ 75C.

Graham