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constant on/off breaks equipment

Discussion in 'Electronic Equipment' started by [email protected], Feb 25, 2006.

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  1. Guest

    can we take it as a fact that some electronic equipment wears out
    faster if you're constantly turning it on and off, while it may last
    longer if you had just left it on the whole time?

    if you think this is true, why do some components wear out while others
    seem to be able to take the on/ off operation?

    and, finaly, judging from that, which catagory do you think an
    ultrasonic humidifier would fall into?

    thanks for any experiences.

  2. Robert Baer

    Robert Baer Guest

    *Switches* wear out, and other mechanical things (although relays are
    a lot more reliable in general than switches).
    A light bulb will not last as long with many on-off cycles as
    compared to being left on until it burns out; the reason is that the
    inrush current mechanically stresses the filament each time.
  3. Chris Jones

    Chris Jones Guest

    There are certainly some components which degrade more quickly when left
    switched on permanently than if switched off for part of the time. Some
    components don't like the thermal cycling caused by being turned on and off
    many times. For most appliances, if I think I will not use it in the next
    hour or two, I switch it off. For the ultrasonic humidifier, I would do
    this, unless anyone has some experience specific to these devices to
    suggest otherwise.

  4. Guest

    can we theoretically deduce if the cycles would be bad for the
    humidifier (and i'm talking about short cycles, 5min on and 5min off)

    if a light bulb doesn't do well with on off cycles, what are some other
    components that similarly act like this

    and what are some components that last longer if turned off for part of
    the time, even if its very often.

    thanks for the replys so far.
  5. Chris Jones

    Chris Jones Guest

    I strongly suspect that laser diodes last longer if they are not on all of
    the time. If the driver circuit is well designed then I think that the act
    of turning them on or off doesn't hurt them much by comparison. Of course
    it is hard to generalise and it will depend a bit on how hot they get and
    whether the different materials used have well matched temperature
    coefficients of expansion etc.

    The metal tracks of ICs slowly get damaged by current passing through them.
    This is called electromigration and is basically caused by the very high
    current density, i.e. the tracks are so thin that the electrons have to go
    very fast to carry normal currents. The fast electrons knock the metal
    atoms out of position, and eventually a break can form in the wire in the
    place where the current density is highest. This is not likely to be a
    problem in a well designed IC if the temperature is kept down. The chips
    are often designed to run for about 10 years continuously at the maximum
    rated temperature and if you can make sure that it runs maybe twenty
    degrees cooler then it would last pretty much forever. Still it is a
    possible wear-out mechanism.

  6. Leave everything on all the time. I used to service 3000+ crts back
    in the day and we found that we would get calls first thing in the am
    when folks turned them on and then found that for the folks that never
    turned them off we had no problems, scientific results, no, but heck
    we stuck with it!
  7. Chris Jones

    Chris Jones Guest

    But sooner or later old computer equipment depreciates to the extent that
    the power to run it continually costs more money than the potential
    increase in reliability is worth. I wouldn't spend >$35 on power in order
    to power my old CRT monitor for a year, just to possibly increase the life
    expectancy by a couple of months, and I doubt that it would increase its
    life at all. I will very likely replace it before it stops working just
    like most consumers. I have always powered off my monitor when not in use
    and I have never had a monitor fail on me, though this is of course a small
    and statistically insignificant sample. There are some devices for which
    the reliability doesn't improve when it is left on continually, e.g. fans,
    probably laser diodes, and some others. There are also environmental
    advantages in switching off unused equipment - provided that it doesn't
    result in you having to buy new equipment in the event of failures!

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