vacuum-safe laptops ?

[Thomas Shaddack]

On Sat, 17 Jul 2004, Tyler Durden wrote:

> Sorry to need educating once again, but I had assumed can-shaped capacitors
> were gone from laptops in lieu of surface mount. Anyone know? (I don't own a
> laptop.)

The can caps can be surface-mounted as well. The leads then look 
different, but the inside is still the same: a metal can with etched 
aluminum strips and an insulator soaked with electrolyte. The magic smoke 
they are filled with also has the same color and smell as their non-SMD 
predecessors.

See also http://www.elna.co.jp/en/ct/c_al01.htm for brief description of 
liquid-electrolyte aluminum capacitors.

There are also some more modern constructions, where the electrolyte is 
solid-state. (The tantalum capacitors, which are more common in SMD form 
than the aluminum ones, use MnO2 as electrolyte and Ta2O5 as insulator. 
The added advantage here is that during a breakdown, the MnO2 layer 
locally overheats and is converted to less conductive Mn2O3, which causes 
the breakdown to "heal". Similar mechanism is used in capacitors with 
solid-state plastic electrolyte.)

I suppose the solid-state caps could be much more reliable in the 
conditions of rapid pressure changes, if they won't have moisture or air 
trapped inside their construction.