Using mobile phone as an internet radio

On Oct 4, 4:28*pm, Phil Hobbs
wrote:
On 10/04/2012 02:57 PM, George Herold wrote:





On Oct 4, 12:43 pm, Jeff *wrote:
On Thu, 04 Oct 2012 10:03:21 -0400, Phil Hobbs

*wrote:
On 10/03/2012 09:41 PM, Jeff Liebermann wrote:
On Wed, 03 Oct 2012 10:32:57 -0400, Phil Hobbs
* *wrote:

I don't know of any data that supports this common idea, but I'd be
interested in reading about it if anybody's actually done the experiment
carefully.

It's an accelerated life test. *The deration curve of the incandescent
light bulb is well known and assumed to be
* * (Vapplied/Vdesign)^-12 to ^-16 * Life at design voltage
http://www.welchallyn.com/documents/Lighting/OEM_Halogen_Lighting/MC3...
See Fig 5 on Pg 5 for the graph. *Nobody wants to wait 1000 hours for
a bulb to blow. *So, they increase the applied voltage, which
dramatically decreases the lifetime down to reasonable test times.
Using a rack of bulbs, they obtain an average (or median) lifetime at
the higher voltage. *Then, they work backwards on the curve to
estimate what it would be at the design voltage.

You can't run an accelerated life test when the exponent isn't known
more accurately than 12 to 16.

True, but I believe that's the range expected from different types of
light bulbs (nitrogen filled, halogen, vaccuum), and not the range
expected for a given device. *I suspect that more accurate exponent
value could be empirically determined for a given device, and later
used only for that device.

Yep. *As I understand it (possible wrong), AC filaments break in the
middle, mostly from vibration flexing.

I don't think so, because there's no mechanism for that, as I said. *The
wire is fully annealed at all times, so there's no possibility of
progressive fatigue failure.

http://en.wikipedia.org/wiki/Incandescent_light_bulb#Reducing_filamen....
* * One of the problems of the standard electric light bulb is
* * evaporation of the filament. Small variations in resistivity
* * along the filament cause "hot spots" to form at points of
* * higher resistivity; a variation of diameter of only 1% will
* * cause a 25% reduction in service life. The hot spots evaporate
* * faster than the rest of the filament, increasing resistance
* * at that point a positive feedback that ends in the familiar
* * tiny gap in an otherwise healthy-looking filament.

Note the photo of the filament with a break in the middle. *When I was
quite young, I would break burnt out AC light bulbs to see what was
inside. *If the filament was intact, the break was always somewhere
near the middle. *If a piece broke off, one end of the broken piece
was usually near the middle. *In later years, I would look at the
remains of DC panel lights (usually type 47 for old Motorola radios)
and noted that the breaks were always near the supporting terminals,
probably due to metal migration.

I suspect that the notion that cycling is hard on bulbs comes from the
way that the bulb often fails at turn-on, when the thinnest hot spot
vapourizes before the rest of the filament has a chance to come up to
temperature and reduce the inrush current.

Yep. *See my comments on the relatively high failure rate on the
40watt theater marquee lamps due to cycling. *The same lamps in the
lobby and foyer were not cycled and seemed to last forever.

I was actually disagreeing with you. *There are lots of possible reasons
for the marquee lights failing prematurely. *I'm not a tungsten expert
myself, so I'd be very interested in seeing actual data that shows a
dramatic shortening of life due to cycling. *I'm not saying it's
impossible, just that I haven't seen any such data.

So much for my anecdotal data. *My theater marquee experience was in
about 1966. *The theater actually did keep records so that they could
stock enough replacement bulbs, but I don't have copies of any of
that.

I tried Googling for similar repetative on-off tests and didn't find
anything. *If I have time, I'll try again. *I must admit that the lack
of test data does look suspicious. *Perhaps sending the idea to
Mythbusters and have them runs a test?

The filament isn't tungsten-plated, it's pure tungsten or a low alloy..
The brightness drop comes from tungsten condensing on the envelope.

Oops. *I thought it was plated.

And the connecting wire isn't plain steel, it's generally Dumet,
http://www.jlcelectromet.com/dumetwire.htm

which is a 42% Ni steel with OFHC copper or nickel plating.

You're making a lot of that up. *I'd still like to see
carefully-collected data.

No, not fabricated. *It's my reliance on my memory in an area that I'm
not familiar with. *I tried Googling for the wire used, couldn't find
much, and made a bad guess. *The plating came from somehow getting
thorium coated tungsten wire used in vacuum tubes mixed up with light
bulbs. *Sorry for the errors and muddle.

Cheers
Phil Hobbs

--
Jeff Liebermann * *
150 Felker St #D * *http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann * * AE6KS * *831-336-2558- Hide quoted text -

- Show quoted text -

Hi Jeff, Phil. * First I know nothing about incandescent bulbs.
But how about this as a model of why turning bulbs on and off might
cause them to fail sooner.

1.) I think we all observe that bulbs tend to blow when you turn them
on.
(unless you knock the lamp over or something.)

2.) I assume that the failure is mostly due to the thinner �hot spots�
on the filament. * Thinner regions heat up faster (higher resistance
with equal current).

3.) Now even if the thinner region doesn�t blow, it still gets hotter
and loses a bit more tungsten than the rest of the filament. * (For
that small amount of time that it�s turning on.) *But still this means
that turning on the bulb causes the thin region to become a bit
thinner.

And that�s it. *Repeated on and off means that the thin region has a
higher average temperature than the thick part of the filament. *It
evaporates faster and fails sooner.

George H.

If the effect is real, that sounds like a good candidate for a
mechanism. * Certainly you'd expect that to be important right near the
end of the bulb's life, so maybe it's important throughout.

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

hobbs at electrooptical dot nethttp://electrooptical.net- Hide quoted text -

- Show quoted text -

Yeah, I was thinking about this while splitting/stacking wood
tonight.
If the time to fail goes as some big power of the voltage
(temperature),
then during turn on, small diameter variations (or defects)
get amplfied.

A 'long life' 40 Watt bulb would fail almost as fast as a 100 W'er.

(Of course I've got my 'lifetime supply' of 100W bulbs, and didn't
budget any for research.)

George H.

On Oct 4, 5:05*pm, Jeff Liebermann wrote:
On Thu, 4 Oct 2012 11:57:21 -0700 (PDT), George Herold

wrote:
Hi Jeff, Phil. * First I know nothing about incandescent bulbs.

I'm still learning (mostly from my mistakes).

It's definitely my mistakes that have taught me the most.

(my latest f-up had to do with short ultrasonic pulses,
and 1/4 wavelength anti-reflection wave-plates...)

I've no problem with your marquee story. Sometimes folk-tales about
rocks falling from the sky are correct.
The data point I offer to Phil is that bulbs fail when you turn them
on. I see no reason why that can't be 'played backwards'. There most
be some GE, Philips, (other) report that documents turn on failure.

George H.

I blundered across this video on tungsten filaments.
http://www.youtube.com/watch?v=DIGqBb3iZPo *3:38
While it doesn't touch any of the issues previously mentioned, it does
include some interesting info on how the filament is made and its
structure.

--
Jeff Liebermann * *
150 Felker St #D * *http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann * * AE6KS * *831-336-2558

On Tue, 2 Oct 2012 22:21:26 +0100, "jim stone"
wrote:

Not being able to find a small internet radio to buy we liked, we got mobile
phone with which we link with wi-fi to a modem router, and use it as an
internet radio.

Keeping the phoned plugged into its charger all the time, we are using it to
play *all-day* background classical music through an amplifier and speakers.

Several of my customers do exactly the same thing. Some play stored
MP3/AAC music, while others stream from Pandora or Slacker. Most use
an iPhone 3G, iPod Touch, or Droid A855 for the wi-fi connectivity.
All have the phone plugged into a charger. No fatalities.

Since the phone has no 'moving parts' unlike a computer, we are wondering if
this continuous playing all day of the phone is going to shorten its working
life ?

It won't hurt the phone in any way. However, the internal battery is
another story. For Li-Ion, battery life is shortened when the battery
is hot, and when it's left at full charge all the time. For details,
see:
http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
Most Li-ions are charged to 4.20V/cell and every reduction
of 0.10V/cell is said to double cycle life.
This is not much of a problem for easily replaceable inexpensive
batteries, such as in the Droid A855, but might be an issue with the
designed obsolescent iPhone series, where brain surgery is required to
replace the battery. Apple has therefore wisely elected to charge
their Li-Ion batteries to 4.1v or what I estimate to be 95% of full
capacity. This greatly extends the battery life and will delay when
you start cursing Apple products to about 3 years.
http://stephenwmoore.wordpress.com/2009/07/21/iphone-battery-life/

Someone mentioned having a phone with a dead wi-fi. I have two Apple
3G iPhones, both with intermittent wi-fi sections. If I turn the
power off on the iPhone for a day, the iPhones will have a working
wi-fi section for about 30 minutes. I also have a third working
iPhone 3G, where the wi-fi has never failed. I've been inside trying
to repair them, and failed.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

In article de99517e-e5e1-4f9d-91e0-
, George Herold wrote:
And that’s it. Repeated on and off means that the thin region has a
higher average temperature than the thick part of the filament. It
evaporates faster and fails sooner.

Won't a thin region of a lamp filament have a higher temperature than
the rest of it all the time, not just when the lamp is turning on?

Rod.
--

On Oct 5, 6:20*am, Roderick Stewart
wrote:
In article de99517e-e5e1-4f9d-91e0-

, George Herold wrote:
And that s it. *Repeated on and off means that the thin region has a
higher average temperature than the thick part of the filament. *It
evaporates faster and fails sooner.

Won't a thin region of a lamp filament have a higher temperature than
the rest of it all the time, not just when the lamp is turning on?

Rod.
--

Hmm, sure, maybe... I really have no idea. But I can't remember ever
seeing a bulb fail after being on for a while. (I'm sure it must
happen.) They almost always go when you turn them on, from which I
conclude that the turn on is more 'stressful'.

Say does Don Klipstein still lurk here? He may have some info on turn-
on failure.

http://donklipstein.com/

George H.

On Fri, 5 Oct 2012 07:43:56 -0700 (PDT), George Herold
wrote:

Say does Don Klipstein still lurk here? He may have some info on turn-
on failure.
http://donklipstein.com/
George H.

Thanks. He has a section on why and how bulbs burn out at:
http://donklipstein.com/bulb1.html#how

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On 10/05/2012 06:20 AM, Roderick Stewart wrote:
In articlede99517e-e5e1-4f9d-91e0-
, George Herold wrote:
And that’s it. Repeated on and off means that the thin region has a
higher average temperature than the thick part of the filament. It
evaporates faster and fails sooner.

Won't a thin region of a lamp filament have a higher temperature than
the rest of it all the time, not just when the lamp is turning on?

Rod.
--


Thin spots will evaporate faster at all times, sure. The main question
as to whether George's mechanism explains the alleged effect is whether,
in a newish bulb, the inrush makes the hotspots exceed 2800K or whatever
the normal filament temperature is, before the the inrush current subsides.

I'd expect that to be more of a threshold effect, because the resistance
of the filament ought to be pretty linear with temperature, whereas the
evaporation essentially turns on at around 2500K, so the hot spots would
have to be pretty thin already for it to do much.

But as I say, I'm far from being a tungsten bulb expert myself.

Cheers

Phil Hobbs

On Thu, 04 Oct 2012 10:03:21 -0400, Phil Hobbs
wrote:

Yep. As I understand it (possible wrong), AC filaments break in the
middle, mostly from vibration flexing.

I don't think so, because there's no mechanism for that, as I said. The
wire is fully annealed at all times, so there's no possibility of
progressive fatigue failure.

Oscillating filament light bulb:
http://www.youtube.com/watch?v=t_DwwNVA-7Q
Whether the earths magnetic field is strong enough to induce such
oscillations is questionable.

While digging for the apparently mythical lifetime test data on
incandescent light bulbs, I've found numerous theories on why
filaments fail. Tungsten evaporation, causing hot spots, is the most
common. One suggested that thermal cycling hardens the tungsten and
makes it brittle. Another suggested that the inrush current causes a
mechanical shock if it hits at the 60Hz peak, instead of at the zero
crossing. Yet another speculates that the temperature differential
between the hot filament, and the relatively cold mounting structure
may cause cracking.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

George Herold wrote:

Hmm, sure, maybe... I really have no idea. But I can't remember ever
seeing a bulb fail after being on for a while.


It happens quite often in TV studios.

On Oct 5, 2:51*pm, Jeff Liebermann wrote:
On Thu, 04 Oct 2012 10:03:21 -0400, Phil Hobbs

wrote:
Yep. *As I understand it (possible wrong), AC filaments break in the
middle, mostly from vibration flexing.

I don't think so, because there's no mechanism for that, as I said. *The
wire is fully annealed at all times, so there's no possibility of
progressive fatigue failure.

Oscillating filament light bulb:
http://www.youtube.com/watch?v=t_DwwNVA-7Q
Whether the earths magnetic field is strong enough to induce such
oscillations is questionable.

While digging for the apparently mythical lifetime test data on
incandescent light bulbs, I've found numerous theories on why
filaments fail.

Grin, the internet as a 'fire hose' of information. I went searching
for something that contained "Philips tech. rev." and found a
reference to the following article,

H. Horster, E. Kauer and W. Lechner — The Burn-out Mechanism of
Incandescent Lamps Philips Technical Review 32,155-164, 1971.

It was referenced in "Illuminating Engineering - Page 32 - Google
Books"

But nothing about turn on failure... sigh.

Here is a patent by some of the same guys at Philips... lots of stuff
about the filament getting hottest in the middle.

http://www.freepatentsonline.com/3868159.html
(Actually a decently written patent.)

George H.



Tungsten evaporation, causing hot spots, is the most
common. *One suggested that thermal cycling hardens the tungsten and
makes it brittle. *Another suggested that the inrush current causes a
mechanical shock if it hits at the 60Hz peak, instead of at the zero
crossing. *Yet another speculates that the temperature differential
between the hot filament, and the relatively cold mounting structure
may cause cracking.

--
Jeff Liebermann * *
150 Felker St #D * *http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann * * AE6KS * *831-336-2558

G