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Discussion in 'Electronic Basics' started by jim stone, Oct 2, 2012.

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  1. Jasen Betts

    Jasen Betts Guest

    It will, but due to the thermal coefficient of resistance of tungsten
    (most other metals are similar) the heating will be even greater when the
    filament heats from cold. The hot spot gains resistance faster, so it
    drops a greater voltage while the rest of the filament is still cold.

    disclaimer: figures made up to illustrate the point

    assume a constant-voltage supply compute the power disipated by he
    thin spot (middle resistor) in each case

    cold ----[100]---[1]---[100]---

    hot ----[1000]-[12]-[1000]----

    during warm-up thin spot warms up fastest.

    start ---[200]---[3]---[200]---

    yeah, it would be a good project for the mythbusters, I'd love to see
    a slow motion film of an incandescent lamp failing at turn-on.
    but could they affor do dedicate their fast camera for long enough.
  2. Jasen Betts

    Jasen Betts Guest

    Digi-Key sent me (in NZ) a postcard by royal mail (from UK) the other day.
    if it's still in the waste bassket on monday it'll check to see if it's a
    preferred spelling thing (eg: "catalog" vs "catalogue") or perhaps it was
    just cheaper to do it that way.
  3. Jasen Betts

    Jasen Betts Guest

    Chinas international mail is heavily subsided. <hearsay> I've heard that
    it's so heavilty subsidised that in some cases they pay the sender
    </hearsay>. while doing the same in the USA would probably help small
    exporters (and therefore the balance of payments) I can't see the
    republican party getting behind subsidising a "state run monopoly".
  4. Gee, good thing this thread was never x-posted there, huh?


    Are all the regs of s.e.b this fucking retarded?


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  5. Isn't the USPS already a state run monopoly which is subsidised?


    Note that it says that the USPS has not DIRECTLY received taxpayer funds
    since the 1980's.

  6. Yeah, we're not doing a thing. You can find somebody else's leg to hump.

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  7. Hi SEB. Well I sent an email to Don klipstein on this topic. And
    have permission to copy his reply.

    <from Don K. below>

    My apologies - I have been off Usenet for a little over a year.
    As for real data on effect of switching causing wear on

    I know some data.

    1: It is true that incandescents often failon cold starts. However,
    know a mechanism where an aging incandescent becomes unable to
    a cold start a little before it becomes unable to survive continuous

    I explain this in:

    2: In incandescent traffic signals, the bulbs for yellow last longer
    for red and green. So even after being switched on and off about a
    million times, on-time is still a significant factor in life

    However, traffic signal bulbs have a more vibration-resistant
    than standard incandescents.

    3: Flashing and chasing marquee lights used to be incandescent until
    cold cathode CFLs became economically available. Cold cathode CFLs
    are special CFLs that are dimmable and blinkable, and flashing them
    does not detract from their life. However, their efficiency is less
    than that of hot cathode CFLs. Some marquees still use

    4: I did an experiment to check for voltage drop in one of those
    now-hard-to-get thermistor-type life-extending "buttons" to attach
    to the tip of the base of an incandescent. The device claimed to
    double the life of the bulb. I found enough voltage drop to account
    for 50-60% life extension. Light output was reduced 13%, and power
    consumption of the combo of the bulb and the thermistor was only
    less than that of a bulb connected directly to the line.

    5: In my experience, incandescent holiday lights that blink last
    than those that don't. However, most of my experience is with low
    voltage bulbs whose short filaments are probably sturdier.

    6: Some incandescents make an audible "ping" when switched on.
    deflection of the filament does not necessarily strain the filament
    past its "endurance limit" - the threshold of causing metal fatigue.

    7: Some railroad crossing signals have a set-up where bulbs have a
    resistor added in series with them for the first half second or so
    that they are on. However, this may be done because of how serious
    the problem is widely said to be, and how serious it actually is
    to me to be much less.

    8: One of my friends had a bathroom fixture with a high wattage bulb
    was constantly run dimmed by a dimmer. He experienced little gain
    life extension. Since his bulbs significantly audibly buzzed, I
    his filaments resonated at the power line frequency or one of the
    line frequency's lower harmonics.

    9: My mother had some incandescent nightlights that had diodes in
    to significantly dim the bulbs - which should have made the bulbs
    for decades. However, they did not.
    One thing I noticed: These 4-watt bulbs had extremely thin
    and with a diode and therefore being off half the time 60 times a
    second, their temperature varied greatly up and down 60 times a
    I could see that from rolling my eyes up-and-down while looking at
    Maybe the filaments at times resonated at the power line frequency
    a lower harmonic thereof. That could easily produce sound too weak
    hear from more than a couple inches away, because such low wattage
    incandescents have a vacuum rather than a gas fill.

    Or, maybe those bulbs do not do well with DC due to high voltage,
    vacuum, and the ends of the filament being close to each other.
    Please see:


    Overall, I am seeing generally that cold starts are not nearly as
    bad as many say they are, but in a few bulbs they can be. The data
    appears to me to be majority in favor of "little to generally no
    problem from cold starts", but it is incomplete.

    I would also suggest reading:


    Hope this helps!

    - Don Klipstein ()
  8. Sod off, aNaL cAkEs.


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  9. I had it "working" a little after all that and an adjustment to the
    potentiometer on the back of the lazer as instructed. However it would
    only read one specific CD and scratched some CD's when it went thru its
    ejection cycle (disks would not spin down before ejection!) so I removed
    the tray and wont use it anymore. Further research indicated AIWA was
    part of a class action lawsuit in the 90's due to their CD players being
    crap. They're out of business now anyway. Good riddance.

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  10. Aiwa is still around as I understand it. They're owned by Sony.
    The biggest problem with their 3-cd models was that so much dust would get
    into the lasers that even cleaning eventually would not be enough and the
    laser would need to be replaced.
    By the way, the lasers were made by Sony, the same pickups used by many
    manufacturers at the time.

    Worked on many of them, the customers were mostly satisfied.

    Later models had sliding covers that covered up the laser lens when not
    playing. This helped but of course was not a perfect solution.

    Mark Z.
  11. Experiments can be very useful.
    I'd worry most about how you turn on the bulbs.
    Maybe just some simple relays?

    1,000 hours isn't all that long. (or are you going to over-voltage
    the bulbs?)
    I guess I'd want at least 10 bulbs in each group. Say 60 watts.....
    1200 kW-hrs.

    That's looking like more money than I'd want to spend on the

    George H.
  12. I haven't seen any new kit from them in any stores for years. Sony
    bought them out and killed it off:

    "Since 2004, however, Sony seemingly began rolling back its support for
    the Aiwa brand, and by 2005 Aiwa products remained on sale in only
    selected territories around the globe. In 2006, Aiwa products were
    discontinued and no longer sold in the market.

    As of September 2011, the Aiwa website still existed to provide
    customer-support telephone numbers for some territories and regions, but
    it also contained many broken links and blank pages. In other regions,
    such as Europe, it redirected to a page on the Sony website stating that
    the Aiwa website had closed. The last apparent update to the website was
    in June 2008.[1]"

    Wanna buy a used laser? Heh...its a 1997.
    We have another one, made in 2001, the tape decks on that one dont work.
    So, to recap: we have two units from failed electronics maker AIWA, and
    both have non-working components. My conclusion: AIWA was rightly killed
    off by Sony since its quality sucked balls.

    Oh, but we also have a SHARP single CD unit from 1991, it works *perfectly*.

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  13. The tape decks have belt problems, like every other brand. The Aiwa's were a
    very cost-effective item at their price point.
    I have no desire to defend Aiwa - I find many of their products difficult to
    service. But it sounds to me like perhaps the problem here may be as much
    the technician as the product.

    Mark Z.
  14. Translation: you get what you pay for.
    Oh snap! But I'm not a technician. No training whatsoever.

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  15. Guest

    They don't. The antennas are separate, even.
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