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Electronic components aging

Discussion in 'Electronic Design' started by Piotr Wyderski, Oct 15, 2013.

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  1. Uwe Hercksen

    Uwe Hercksen Guest

    Hello,

    but relays with open contacts exposed to the air are not very reliable
    over a long time. Cleaning them may help, but only for some more years.

    Bye
     
  2. Jasen Betts

    Jasen Betts Guest

    Datasheets typically quote a million on-off cycles at 1/5 rated current
    ,resistive load
     
  3. Chris Jones

    Chris Jones Guest

    I have thought about a similar problem from time to time, except that I
    was thinking of designing something for maybe 1000 years or more of
    storage followed by being expected to operate. I assumed that the whole
    equipment should be hermetically encapsulated and put somewhere cool, so
    I'm only thinking about inherent aging.

    I think larger geometry chips may well be ok (provided they don't rely
    on stored charge like EPROMS and FLASH). (Also I think the patterns of
    metal in a chip that is passivated with oxide might well be visible
    after many thousands of years, and be a fairly dense and long-lasting
    way to store information. Because consumer chips also get made in very
    high volumes and end up discarded in landfils all over the world I
    expect that it will be possible to find be copies of a few on-chip
    inductors that I designed even after a very long time.)

    My guess is that film capacitors like polypropylene might do alright for
    a long time.

    I have observed high-K ceramic caps that have lost quite a lot of
    capacitance even after a few years but they could be restored by
    reheating when they are re-soldered, (which I consider cheating in this
    context, unless the equipment can do that itself).

    Even for much shorter periods, batteries seem to be one of the worst
    causes of permanent damage due to electrolyte escaping, though I haven't
    seen a lithium coin cell leak so far.

    Electrolytic caps seem to be able to last many decades if the equipment
    is turned on often enough to keep the dielectric formed. If the
    equipment is just stored for decades with no power applied then the
    dielectric degrades and if power is then applied suddenly they fail due
    to overheating, or if they are used in a low current circuit the leakage
    just makes it not work (maybe only temporarily). Even when the
    electrolytics are kept formed, it is also necessary to plan for the ESR
    to increase and the capacitance to decrease, otherwise the circuit will
    not last long.

    I recall reading that inductors (chokes) used to be connected such that
    the fine wire was more negative than the iron core, rather than the
    other way around, so that any moisture didn't cause electrolytic
    corrosion of the thin wire if there were cracks in the enamel.

    I have seen neodymium magnets which didn't last long (plating fell off
    and magnet turned to powder) though I have seen others that didn't have
    that problem.

    I suspect that hermetic metal can tantalum capacitors have different
    reliability from the dipped style and perhaps the surface mount ones are
    different again. I have had a dipped tantalum cap go short circuit in an
    always-on battery charger application (trickle charger fed from a large
    series resistor) where I don't think it was ever subjected to high dv/dt.

    Desinging in redundancy would help a lot, and if the redundant copies
    are different and each avoid using a different type/brand of component,
    that might help against the difficulty of predicting failure mechanisms.

    I found this project slightly interesting, though I wouldn't have done
    it the same way:
    http://longnow.org/clock/

    Chris
     
  4. Tim Williams

    Tim Williams Guest

    I don't know about the dry type (being mil spec, hopefully their failure
    modes are well understood and controlled), but there is also a wet type
    (which also has very low leakage, once stabilized).

    Tim
     
  5. Joerg

    Joerg Guest

    Can you talk to the electronics in our Hammond organ about that? It is
    53 years old now and no signs of fatigure. First set of tubes. Then
    there is the Sachsenwerk radio from 1939. When I donated it to a museum
    a couple of years ago it ran just fine and likely still does.

    Depends on how well the components are built they can easily outlast
    humans. I have a radio with the first "IC" in there from the roaring
    20's. Last time I fired it up was over 15 years ago but it worked:

    http://www.radiomuseum.org/tubes/tube_3nf.html

    You can still buy it used:

    http://www.ebay.com/itm/GERMAN-RADIO-RECEIVER-LOEWE-OE333-with-3NF-TUBE-C1927-/330954445929

    Or look at the DC-3. It's still hauling lots of freight and passengers.
    These old airplanes are used for hard jobs, I think this one was built
    in 1937:



    My dad's old IBM 5100 from the mid-70's is still there :)
     
  6. Don Y

    Don Y Guest

    Hi Paul,

    That's the problem. You can try to maintain legacy iron for
    this purpose. Or, write a VM to host it. But, hardly
    "cheap" or "sure fire" solutions...

    [Anyone have a GE-645 emulator to run the original Mutt-Licks
    binaries?? :-/ And that's just *barely* 50 years! ]
     
  7. miso

    miso Guest

    Mosfets have a threshold voltage shift related to how many times they
    are switched. The rule of thumb is your chip should be able to last 10
    years at the maximum clock frequency. But of course, this isn't hard and
    fast or even written down.

    Basically a logic circuit will still work if the fet threshold voltage
    changes over time. But if there is some critical timing and the fet
    threshold voltage got larger, it will have less drive and thus the chip
    becomes slower.

    The threshold shift effect has been around since the 1um days. I believe
    it is related to hot carriers. All sorts of foo was created over the
    years to keep this problem tolerable.
     
  8. josephkk

    josephkk Guest

    Try looking at some serious long term infrastructure systems. There is
    plenty of SCADA that has already lasted as much as 60 years or more. Lots
    more in heavy industries (refining, major metal mills, chemical plants,
    water treatment, wastewater treatment, etc.,) where replacement costs get
    really really big.

    ?-)
     
  9. josephkk

    josephkk Guest

    But Space has severe thermal management issues, it is a really good
    insulator after all. Also contact erosion is a major player in relay
    life, the design has to control that or the system dies early. I know i
    did some testing of relays for space use.

    ?-)
     
  10. Robert Baer

    Robert Baer Guest

    A number of stupid people have totally wasted their time and money here.
    Plain old WEAR is going to put a severe crimp in that impossible 10K
    year "timeframe".
     
  11. I don't suppose that those systems are still running without having had some
    maintenance (board swaps, repairs etc). Would you wish to guarantee that any
    system you design today will still be operating that far in the future.

    I don't know where your utilities are based but I am certain that the ones
    near me have all upgraded their systems over the years (just to cope with
    demands).

    --
    ********************************************************************
    Paul E. Bennett IEng MIET.....<email://>
    Forth based HIDECS Consultancy.............<http://www.hidecs.co.uk>
    Mob: +44 (0)7811-639972
    Tel: +44 (0)1235-510979
    Going Forth Safely ..... EBA. www.electric-boat-association.org.uk..
    ********************************************************************
     
  12. Tim Williams

    Tim Williams Guest

    What's the mechanism of that, residual sodium (or etc.) ions??? Hot
    carriers don't just go loitering in pure silicon...

    Tim
     
  13. Don Y

    Don Y Guest

    Hi Joseph,

    Yes, but I suspect each of those systems are actively *maintained*.
    I.e., *AS* parts of them fail, they are repaired and replaced.
    This is very different than a "hands off" approach (e.g., deep
    space probe that can't be "serviced" after its launch).

    There are lots of things you can do to improve reliability,
    probabilistically -- not sure how *deterministic* those efforts
    would be, though! E.g., entering an electronically controlled
    "stasis pod" and HOPING you've done the engineering right!
    (then, again, if you *didn't*, YOU sure will never know! :> )

    But, a lot of that is predicated on having some idea as to usage
    patterns, extremes, etc. E.g., how you select a battery/charger
    for a cell phone is very different than for a power tool or a
    UPS.

    [As an aside, what gives with the pricing on NiMH AAA cells? It
    seems like ~$3/ea is the going rate. Sheesh! Cheaper to buy
    a boatload of alkalines...]

    Look, for example, at WE's designs for subscriber end devices (where
    the sheer NUMBER and physical distribution made upgrades/replacements
    virtually impossible!). Contrast that with their (still robust!)
    designs for CO equipment (costlier but far easier to replace than
    the subscriber end)

    I've had occasion to design high volume, long service life, high
    repair/replace cost devices and it's REALLY a completely different
    world! Something like 10 years is relatively easy. When you
    start talking 30 or more years, you start actively gauging whether
    or not you could, perhaps, be "gone" and NOT have to worry/know
    if you've screwed up! :>
     
  14. Don Y

    Don Y Guest

    Hi Paul,

    They've been replacing natural gas lines throughout the neighborhood
    and certain parts of town. Years ago, they started replacing the
    individual "service drops" for each residence (interesting process!).
    Then, last year, started replacing (and upgrading) the "mains" that
    feed the neighborhood (even *more* interesting process!).

    The former was part of a regular upgrade process -- original lines
    were ~30 years old.

    It's unclear if the latter was also part of "scheduled maintenance"
    or, instead, reflected a city-wide gas shortage a couple of winters
    ago (simply didn't have enough distribution capacity to cope with
    an unusually cold spell and ended up having to turn off the supplies
    to parts of the city so that other parts of the city had ample
    pressure).

    Interesting situation to find yourself without *gas*. Electricity
    you aren't terribly surprised to find it "out" (though rare, here).
    Losing water tends to raise eyebrows as it is REALLY rare. Gas
    even more so! The only utility (interesting observation, this!)
    that you *never* expect to lose is *phone* (land line).

    [Having lost it, once -- nearby lightning strike fried the electronic
    phones on our service -- it was really unnerving. You just NEVER
    expect to lift the handset and NOT get dialtone! Gotta wonder how
    many 9's in *their* availability figures! :> ]
     
  15. Phil Hobbs

    Phil Hobbs Guest

    NYC just finished the replacement for the 1917 aqueduct. Big job.

    We've never had the gas or the water go out, but as far as phones go,
    you live a very sheltered life. We finally bailed on POTS, despite the
    very great theoretical advantages of central-office power, because the
    Verizon people we had to deal with were so uniformly incompetent.

    Getting anything changed, or trying to get them to grasp the concept of
    starting a home business and then moving to commercial space, took
    several phone calls and at least a few hours of pain per time. They
    apparently had no method whatsoever for having one person understand
    what the actual task or problem was, or even for making notes. It all
    had to be rehashed again each phone call, to a not-very-motivated and
    not-very-bright listener. I suppose that nobody who could find another
    job would work there. (At one point we did find one guy who actually
    cared, and knew how to get things done, but he worked on the other side
    of their Chinese wall between commercial and residential accounts.)

    I eventually concluded that an organization that incompetent couldn't
    really be relied upon to look after their central office batteries
    either. So we eventually changed to cable, and keep spare batteries for
    our cell phones.

    The Verizon sales reps call at the office a couple of times a year to
    ask me to switch to their service, and they're always confused when I
    burst out laughing.

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC
    Optics, Electro-optics, Photonics, Analog Electronics

    160 North State Road #203
    Briarcliff Manor NY 10510 USA
    +1 845 480 2058

    hobbs at electrooptical dot net
    http://electrooptical.net
     
  16. Don Y

    Don Y Guest

    Hi Phil,

    I've lived in 5 different states and never had a phone issue aside
    from the lightning strike (in Colorado). I had a flakey connection
    in Chicagoland, once -- but traced it to a length of cable that had
    fallen on the exhaust plenum for the gas furnace (the wire was nice
    and toasty-crunchy! :> ). Lots of *noise* on this (below grade)
    line in the days when I used a modem -- but that was traced to
    water migration in the buried cable.

    In each case (save the Colorado one), I was still able to make and
    receive calls on the line.

    As to the competence of the folks we have had to deal with "in the
    sales office", that's another story. Took us *6* calls to get our
    DSL disconnected. And, in the process, they managed to disconnect
    our *phone* as well! (the 6th call was to get phone service restored).

    Always nice to see the "this phone call may be recorded for quality
    purposes" come back to bite them in the ass, later! :>
    So, you've never actually LOST dialtone?

    Neighbors routinely lose their cable service. I wouldn't rely on it
    for a "reliable" connection. A friend was recently spooked when she
    was having "chest pains" and found her cell phone unreliable -- and
    no "land line" alternative available!

    And, we don't use cell phones (why have to own *two* phone services
    just to protect against *one* -- or both! -- being unavailable?)
    In some areas, TPC is replacing copper "land line" circuits with
    wireless. Wanna bet they don't give the same availability levels??

    You might find the folks who do the actual plant maintenance are
    of a different caliber than the sales droid/order takers (which,
    at least here, are located in another *state*!).

    E.g., when I was having line noise problems, the tech that came
    out to check the line initially saw "good numbers" and was puzzled
    at the complaints I was making (I sat outside with him while he was
    checking the line). He sat and watched the line for perhaps 15
    minutes before the noise floor shot up dramatically: "Holy cow!
    Can you even *talk* on that line??" (Yes, but a 56K modem can't!)

    Of course, the only solution he had was to switch us to a different
    pair...
     
  17. Charlie E.

    Charlie E. Guest

    On Thu, 17 Oct 2013 10:09:09 -0400, Phil Hobbs
    Welcome to the wonderful world of unions! You can't fire them, you
    can't discipline them, all you can do is put them in a job where they
    can't cause too much damage... :-(

    Actually, CO's usually have very good maintanance. They have
    'routines' that need to be performed every so often on a schedule,
    that are then verified on a similiar schedule. A lot of things are
    also automated, but most important, the jobs are 'interesting' so the
    tech's usually care a bit about how things go...
     
  18. All this stuff will die fairly quickly (days) if there is a severe
    problem. If that ever happens, those folks affected are going to be in
    a world of hurt. Once the water supply fails, the wastewater treatment
    won't be far behind because it depends on a continous flow of water.
    This might be the real threat of EMP and the weapons (carbon
    filaments, smart bombs) that destroy electrical and water treatment
    systems- by taking out utilities over a wide area, people will start
    to die within weeks and they'll be in no mood to do anything but try
    to keep themselves alive.

    I've never seen an unexpected loss of natural gas or water pressure
    (i.e. not due to scheduled repairs or maintenance). I imagine a water
    main bursting would result in a loss of pressure to some homes and
    businesses. Not paying bills might result in a sudden loss of gas
    pressure. ;-)

    The last little bit of phone line is more prone to problems, IME. POTS
    must be 100-1000x more reliable than internet based services. OTOH, we
    have many options to POTS these days, so a single point failure isn't
    devastating.
     
  19. We had water cut off for two weeks... floods inundated the regional
    waterworks, located close to the river of course. Contaminating the
    water treatment tanks with raw sewage.

    Yummy!

    [...]

    <https://www.google.com/search?q=tewkesbury+floods&tbm=isch>
     
  20. Don Y

    Don Y Guest

    Hi Spehro,

    I'm curious as to how resilient our muni water supply is. As most
    of it is derived from wells scattered around the city, a *local*
    outage typically takes out just one or two wells (e.g., there is
    a well three blocks from here). Presumably, the areas immediately
    serviced by the "local well" can tap into excess supply in the
    system -- though probably at reduced pressure in that local area
    (I don't think the mains *into* an area are sized to truly support
    the needs of that area; rather, to support the *surplus* water
    SOURCED from that area!)

    As we have no real "surface water" to speak of (there are a few
    spots for folks who are willing to think *hard* about this), I
    suspect a city-wide outage would leave us *all* without water.

    (It's possible there is a dedicated backup line for each well pump
    but I can't say for sure)
    People expect others to take care of them. Amazing how UNprepared
    (not UNDERprepared but UNprepared!) people are, in general. As if
    "it can't happen here". :< Folks are puzzled when they see lights
    on in our house while *they* are experiencing a power outage...

    I suspect when something dramatic happens, most folks will pile into
    their cars and try to go <somewhere> in the hope that <someone> will
    take care of them, there! :>

    (A friend is responsible for much of the state's disaster preparedness.
    Each time we visit, I try to pick his brain a wee bit more for clues
    as to what "they" think will happen -- not that I put much stock in
    their assessments! :-/ )
    Water mains seem to break with some regularity regardless of where
    I've lived. Or, get "excavated" unintentionally ("Oooops!").

    I've seen gas lines "dug up" twice in this neighborhood -- once by
    a neighbor using a mini back hoe to install a new electric service
    and playing too fast-and-loose with the "shared trench" that ALL
    his services were routed through; another time when a construction
    crew snagged the main on the other side of the neighborhood (and
    frantically worked to obscure the Blue Stake markings so they could
    claim the gas line wasn't marked! :> ). But, in each of those
    cases, the supply to the neighborhood wasn't in jeopardy (electric
    and gas services are "multiple feed", here -- not sure about other
    utilities -- so even snagging a main just means that portion of
    *that* main has to be pinched off)
    But they also rely on power, etc. I think a cell tower has ~5 hours
    of backup capacity? And, if there's an outage in a part of town,
    then *all* the towers in that part of town "go silent" (eventually).

    Consider the 9/11 experience, Katrina, etc. and how well we fared.
    Interesting to consider how technology could be EFFECTIVELY deployed
    in those scenarios.

    E.g., a group I was affiliated with proposed creating "doctor-in-a-can".
    Essentially, a doctor's examination room in one of those full sized
    storage containers. Examination table, X-ray, autoclave, generator,
    water supply/purification, "supplies", etc. The thinking being you
    can put one on a truck and get them to a disaster area within hours
    and "ship" the doctor from a third location. More durable than a
    "tent" and able to carry the heavy supplies that would be accessories
    in a "tent solution" (e.g., large supply of water, propane, etc.)

    I've mused over how to make phone service available to neighborhoods
    while somehow constraining traffic (i.e., a portable cell tower
    seems the ideal solution -- except "Gabby" will get on the line
    and just yack away as soon as she gets through. Any solution
    that silently rations service will result in folks spending hours
    just trying to make a call!)
     
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