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Solid Capacitor Motherboards Introduced
jckrbbt writes with news that Gigabyte has introduced solid capacitor motherboards in its Intel 945 chipset products. From the article: "[S]olid capacitors have a higher tolerance for higher temperatures and they also perform better with higher frequencies and higher current than electrolytic capacitors. The superior heat resistance and better electric conductivity will allow PC enthusiasts to tweak the highest levels of performance from their system without fear of excessive capacitor wear or exploding capacitors."
I have seen them last less than a year. All you have to do is check where the capacitor is from. If it is from China (which is likely), then it has a high probability of failing very quickly. This is due to their stealing the formula from a Japanese company who became aware of the attempted theft and fed the women a recipe from the early 60's (and well known to hold up for only a year).
The standard life test for an electrolytic capacitor is 1000hr at rated temperature. For most consumer equipment, this is 85C oe 105C depending on which electrolyte is used (and price paid). The life of electronic components doubles for every 10C reduction in temperature. At end of life, an electrolytic caacitor is allowed a 50% loss of capacitance and doubled ESR. For most cases these caps work fine (provided the designer included margin). In a PC application, it is reasonable to expect operating temperatures of about 45C to 55C. This would mean lives between 8000hr and 32,000hr.
I find it interesting that the solid electrolyte caps have finally found a home. These have been around fo about 20 years in one form or another. Maybe now the price will start falling and the small wet electrolytics will go the way of the vacuum tube.
so many old computers work so well.
Capacitors are generally used for filters and timing circuits. The motherboard I'm running right now has a capacitor at the edge of the AGP slot that I accidentally crushed (hey, I thought the new video card was just tough to push in, sue me). I only noticed it because the computer refused to boot until I cleaned the guts of the cap off the motherboard, and it runs just fine since then. Perhaps it won't deal with certain line noises anymore, or some USB port hardware runs 15 times as fast, but I'd say that I'll never notice either with this getup. My mother had a TV that was perhaps 20 years old. One day a cap (audibly) blew, and the only difference was that the scan controls no longer kept the picture entirely within the screen, sort of like a permanent 125% magnification, with the extra running off all four edges. She watched that tv another year or two before finally buying a new one.
I see VERY few computers failed due to a cap problem before they are retired on account of being too old to be useful anymore. The most common component I see fail is the HD, which is no surprise given that it's mechanical. This could be useful for devices that are good for 25 years, but comptuers tend to get thrown out after 5.
Agreed. Tantalum capacitors have much better performance than electrolytics in most circumstances. However, there is outstanding debate about whether the use of tantalum capacitors is ethical, as tantalum is just about the rarest element that's actually used in the electronics industry and most of the deposits are in developing countries. Accusations have been levelled that electronics manufacturers are going to inordinate lengths to secure tantalum deposits, and the people who live there are the losers (especially since the by-products of processing tantalum ore are decidedly unpleasant).
I try to avoid using tantalum capacitors in my own designs as far as possible, trying to keep to NASA's guidelines for component derating when using electrolytics. Where I need precision capacitances I design the circuit so that a ceramic NP0 or similar EIA Class 1 capacitor can be used instead. I haven't had any capacitors fail yet.
Pirate Party UK
Compared to tantalum capacitors, these capacitors reach much higher capacities at the same physical volume, and the same or better ESL/ESR.
See for example here:
These aluminium electrolytic capacitors, with a solid conductive polymer electrolytic find their way even on most current mainboards, most often in the CPU DC-DC convertor circuits. They're usually easily recognizable from classic electrolytics by their small size and metal casing without a plastic sleeve.
A benefit from an all-solid-polymer capacitor mainboard is dubious, since classic alimuium electrolytic capacitors work just fine in many roles they're needed for, particularly in low-ripple-current situations.