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.