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Glass encapsulated components, what are they used for?

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Used for very high ohmic circuits, e.g. "electrometer" amplifiers to prevent against leakage currents caused by air moisture. More common for multi GOhm resistors.

smd capacitors encapsulated into glass
and still surface mounted?
 

Used for very high ohmic circuits, e.g. "electrometer" amplifiers to prevent against leakage currents caused by air moisture. More common for multi GOhm resistors.

and still surface mounted?

You know that I mean chip SMD capacitors encapsulated into glass, don't you?
 

You know that I mean chip SMD capacitors encapsulated into glass, don't you?
Not actually. It's a very vague description that can mean a lot of different parts. Are you even sure it's a capacitor.
 

Not actually. It's a very vague description that can mean a lot of different parts. Are you even sure it's a capacitor.

Not the link I posted, these are resistors, but the ones I have yes they are capacitors, chip smd capacitors encapsulated into glass and leads are soldered onto them and extend outside of the glass. I wonder what is the use of such a component they must have a reason to encapsulate it into this expensive package.
 

A chip capacitor encapsulated in glass has unlikely soldered wires. More likely welded. And it's a wired rather than SMD component…

Reasons are probably similar to resistor glass encapsulation.
 

Hi,

FvM is right about both.

Didn't know these existed, just nice to know, thanks.

**broken link removed**

**broken link removed**
 
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    neazoi

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Glass encapsulation is used when you want to completely seal the component from any effects of humidity and moisture.
It's expensive but more effective than any other sealing method.
 
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    neazoi

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Glass encapsulation is used when you want to completely seal the component from any effects of humidity and moisture.
It's expensive but more effective than any other sealing method.

I have seen also glass encapsulated varistors in common ADSL modems and telephone answering machines!
It could be also thermal issues as well as high voltage-related issues, as glass is a good thermal and voltage isolator.
There might be also applications (gas sensors?) where the chemical may corode the "paint" around the resistor and glass could be a perfect solution, although I have not investigated if this is true.

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Hi,

FvM is right about both.

Didn't know these existed, just nice to know, thanks.

**broken link removed**

**broken link removed**


The first link gives a good overview of what FvM mentioned, thanks!
The second is not related to glass encapsulation of capacitors but it refers to glass dielectric capacitors, which is another story.
 

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