Somewhat OT: Long term design
in [Design]
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From: Jan Panteltje on 16 Jan 2010 09:09 On a sunny day (Sat, 16 Jan 2010 13:30:54 GMT) it happened nico(a)puntnl.niks (Nico Coesel) wrote in <4b51bf27.575498125(a)news.planet.nl>: >Tantalums are very prone to failure. Not if you use them right
From: Jim Thompson on 16 Jan 2010 10:37 On Sat, 16 Jan 2010 00:33:31 -0800, Robert Baer <robertbaer(a)localnet.com> wrote: >Sylvia Else wrote: >> John Larkin wrote: >>> On Fri, 15 Jan 2010 11:19:34 -0500, WangoTango >>> <Asgard24(a)mindspring.com> wrote: >>> >>>> In article <hio9k9$fsu$1(a)news.albasani.net>, >>>> pNaonStpealmtje(a)yahoo.com says... >>>>> On a sunny day (Thu, 14 Jan 2010 17:54:31 -0500) it happened WangoTango >>>>> <Asgard24(a)mindspring.com> wrote in >>>>> <MPG.25b96ab48fc5c5b698ae28(a)news.east.earthlink.net>: >>>>> >>>>>> In article <035f8778$0$1309$c3e8da3(a)news.astraweb.com>, >>>>>> adrian(a)qq.vv.net says... >>>>>>> Maybe you could ask how far in the future you have to go before >>>>>>> your 'device' becomes unrecognisable ? >>>>>> What are you talking about? >>>>>> I've watched TV and not only do those guys instantly recognize >>>>>> millennium old devices, they recognize millennium old ALIEN >>>>>> devices, and they all invariably function. I would be more >>>>>> interested in a power source that could just sit for that period of >>>>>> time and still be useable, >>>>> >>>>> Solar. >>>>> >>>> Really....do we know what a solar cell will do after 1000yrs of sitting? >>> >>> Good cells are fairly klunky monocrystalline silicon PN junctions. >>> They'd probably work fairly well after a million years if stored >>> properly. >>> >> >> This is where I wonder about difusion. Will those doping atoms stay put >> over those sorts of time scales, or would we end up with a piece of >> silicon pretty much equally doped throughout with both doping materials? >> >> Sylvia. > CK722s were made with relatively impure chemicals and processed WRT >what is available today, and i suspect the base junctions were not all >that swift - but there are some CK722s that have reasonable >characteristics today. > Tough to extend that "decay" to silicon solar cells, but may give a >crude guesstimate as to worst case expectations.. I have some CK722's and also CK760/61 dating from ~1956. When I get a moment I'll test them. ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
From: John Larkin on 16 Jan 2010 11:35 On Sat, 16 Jan 2010 13:30:54 GMT, nico(a)puntnl.niks (Nico Coesel) wrote: >"Tim Williams" <tmoranwms(a)charter.net> wrote: > >>"John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message >>news:3mbtk55eiaskjbllse9ceknp3lblra9tal(a)4ax.com... >>> Aluminums fail by drying out, through water vapor leakage through the >>> rubber seals. That's a wearout mechanism. >> >>Al Po's? >> >>Generally considered as good as tantalum and fairly indestructible, aren't >>they? Kind of new to use for millenium hardware though. > >Tantalums are very prone to failure. I avoid them if I can. Even >electrolytics are better because they don't cause a short. Nowadays I >use the MLCC capacitors where I can. Tantalums are fine as long as their peak current (ie, dV/dT) is limited. Of course, that makes them useless for most places you'd like to use them. I sometimes use them on linear and switching regulator outputs. I make sure that dV/dT is controlled and derate them 2:1 or better 3:1 on voltage. They do have nice ESR numbers, ideal for a lot of regulators that don't tolerate all-ceramic loads. John
From: Spehro Pefhany on 16 Jan 2010 12:02 On Sat, 16 Jan 2010 14:09:08 GMT, the renowned Jan Panteltje <pNaonStpealmtje(a)yahoo.com> wrote: >On a sunny day (Sat, 16 Jan 2010 13:30:54 GMT) it happened nico(a)puntnl.niks >(Nico Coesel) wrote in <4b51bf27.575498125(a)news.planet.nl>: > >>Tantalums are very prone to failure. > >Not if you use them right Wot mostly consists of leaving them safely on the reel. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" speff(a)interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
From: Jan Panteltje on 16 Jan 2010 12:12
On a sunny day (Sat, 16 Jan 2010 12:02:26 -0500) it happened Spehro Pefhany <speffSNIP(a)interlogDOTyou.knowwhat> wrote in <g8s3l5lah5gm8n12mlrsnvj1eq0v6jfcef(a)4ax.com>: >On Sat, 16 Jan 2010 14:09:08 GMT, the renowned Jan Panteltje ><pNaonStpealmtje(a)yahoo.com> wrote: > >>(Nico Coesel) wrote in <4b51bf27.575498125(a)news.planet.nl>: >> >>>Tantalums are very prone to failure. >> >>Not if you use them right > >Wot mostly consists of leaving them safely on the reel. Well, then they still may fail ;-) Just that you won't know about it. But on the more serious side, I have never had one go kaput, I like them because of low ESR and small size. They do not dry out, some have been on for 20 years... I have seen exploded ones cause damage in equipment, most likely because they were put in in reverse... I put one in (actually a whole series) in reverse myself one day, because the + was marked with a big -- That came out when the first one was tested, and the resistor in series with it burned a hole in the PCB. That was supposed to be a fusible resistor, I have now learned that metal film resistors do not fuse very well. |