Disc capacitor coating

[David Harmon]

What is that stuff, that the old fashioned tan ceramic disc
capacitors are dipped/coated in, anyway?

 

[Don Bruder]

What is that stuff, that the old fashioned tan ceramic disc
capacitors are dipped/coated in, anyway?

Slip - AKA "Clay mixed with so much water you can pour it"

Once it dries, it gets baked to turn it into (wait for it...) ceramic!

 

[johnjd]

I think he means the brown waxy ( it might even be wax? ) outside of
the componet.

 

[Don Bruder]

I think he means the brown waxy ( it might even be wax? ) outside of
the componet.

That's just a wax moistureproofing coat because the ceramic itself is
porous. (Think unglazed flowerpots and how they'll "ooze") Without it,
the value would be all over the map with changes in humidity.

The main body, and the dielectric between the plates, is just standard
slip/clay.

 

[Tim Williams]

The main body, and the dielectric between the plates, is just standard
slip/clay.

If barium titanate counts as clay, anyway. But last I checked, clay was an
hydrated aluminum silicate.

It's handled the same, though.

Tim