Capacitor with 105 degree celsius ?

I assume you are wondering why someone might specify such a part ( T >=

105C, MTBF 8000 hrs)

There are many places we routinely put electronic equipment where the ambient temperature can reach those levels (although we prefer them not to).

One example is in aircraft - if there's circuitry near the leading wing edges of a modern jet aircraft, the temperature might easily attain

100C (friction between the external air and the wing cause the heating) and we do have circuitry there - slat sensors for example. There are few circuits that don't require a capacitor (for bypassing / filtering) somewhere. You have obviously found one that is going into a harsh environment.

On another note, the temperature within a box stuffed with electronic equipment is going to rise above external ambient - the only question is how much.

The spec limit for most military parts is usually -55C to +125C, incidentally.

Cheers

PeteS

Another application for high(er) temperature components is the automotive industry. Inside of an automobile computer module, on a hot day, under the hood (bonnet) the ambient temperature can reach 65C. Then, if the automobile is started, some of the semiconductor junctions can quickly reach 85C or higher with the surrounding components heating up almost as high.

A properly designed system would rarely use components that were only rated for the maximum stressors (temperature, voltage, etc.). Components are generally de-rated, so that 105C capacitor might be used in such an automotive application.

BTW, I design space and military systems and we have to use components rated for -55C to +125C almost exclusively. Some of the semiconductors are rated for even higher temperatures.

Thanks for your reply, I remenber i dementle one of the branded hair dryer, i found a simple circuit with a E.capacitor hide inside the heater coil. The reason that the capacitor would not burn out due to a motor fan turn on when ever you switch on the hair dryer.How ever i will not design such like this with high risk if the motor fan slower than before due to some problum like the grease dry out in the motor bearing, a agree with me ?

thousend

think

--
_Only_ 8000 hours?  Downhole equipment is routinely expected to not
only survive, but to work in environments in excess of 200°C, so that
2000 hours gets eaten up pretty quickly.

--
Dunno...

know

thousend

you think

Besides the heat of drilling, what is the temperature at say 4000 feet?

Hi John. What kind of Downhole equipment is? you will expect the solder tin melt when it reach 187 C. do you mean the electronic circuit board in the downhole ?

--
http://www.google.com/search?hl=en&q=downhole+temperature+pressure

when it

The temperature below the sea bed is way cold!!! I expected it to start getting hot but then the first site wasn't drilling too deep ... < 600 meters below the sea bed.