Using mobile phone as an internet radio

[Jeff Liebermann]

On Wed, 03 Oct 2012 10:32:57 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> 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/MC3544HPX_Catalog_2_11_09.pdf>
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.

When I was specifying lamps for a direction finder for the USCG, I had
to deal with minimum lifetime specs. I asked the vendor (Dialight)
how they tested their T-1 3/4 bulbs and was told that they did an
accelerated lifetime test on a few bulbs from each lot to insure
adequate lifetime along with the usual sampled 1.5% AQL failure test.

Electromigration is a smaller effect in an AC bulb, since
the leading order effect cancels.

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

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.

The tungsten in the lamp is run within a few hundred kelvins of its
melting point, so it's always in the fully annealed state, which ought
to mean that there are no metal fatigue mechanisms operating, just
material migration due to sublimation.

Yep, but different failure mode. When the extremely thin layer of
tungsten plating evaporates, the light becomes dimmer. Below some
brightness level, it is considered to have failed. However, most such
tungsten coated filaments fail due to corrosion of the base steel
alloy wire which is exposed to the internal gases inside the bulb
after the tungsten evaporates. The gases (mostly nitrogen and some
argon) are inert, but there's a little water vapor outgassing from
heating the glass envelope, which eventually corrodes the filament.
Other failure modes are hot spots and notches caused by manufacturing
variations and tungsten evaporation.

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

 

[Jasen Betts]

On 2012-10-02, jim stone <tgh6h56nzh@mail.invalid> 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.

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 may be bad for the battery

--
⚂⚃ 100% natural

--- news://freenews.netfront.net/ - complaints: news@netfront.net ---

 

[Jasen Betts]

On 2012-10-03, Geoffrey S. Mendelson <gsm@mendelson.com> wrote:

My choices are to once a week clean out a jam, and clean the feed roller;
print something everyday (a waste of paper)

load the paper tray with scrap paper, use the bypass when you want to
print something for real.

another option is to make a document with no ink and print that each day
at the end of the week collect the blank pages from the output tray
and put them back in the input tray.

--
⚂⚃ 100% natural

--- news://freenews.netfront.net/ - complaints: news@netfront.net ---

 

[chris]

On 03/10/2012 00:49, William Sommerwerck wrote:

"David Woolley" <david@ex.djwhome.demon.invalid> wrote in message
news:k4fq2r$ics$1@dont-email.me...
William Sommerwerck wrote:

My new computer has a solid-state "hard disk", and you
wouldn't believe how fast it boots up, or how fast programs
start to run.

These, if flash memory, do have a definite wear out mechanism,
although they do try to avoid writing to the same spot, even if the
software does, to mitigate this.

Correct. SSDs are an exception. They contain "leveling" software that makes
sure the disk is written to evenly. The Crucial disk I use is spec'd at
about 40TB of total writes.

For most usage scenarios the theoretical lifetimes of modern SSDs are
longer than HDDs.

 

[Phil Hobbs]

On 10/03/2012 09:41 PM, Jeff Liebermann wrote:

On Wed, 03 Oct 2012 10:32:57 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> 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/MC3544HPX_Catalog_2_11_09.pdf
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.

When I was specifying lamps for a direction finder for the USCG, I had
to deal with minimum lifetime specs. I asked the vendor (Dialight)
how they tested their T-1 3/4 bulbs and was told that they did an
accelerated lifetime test on a few bulbs from each lot to insure
adequate lifetime along with the usual sampled 1.5% AQL failure test.

Electromigration is a smaller effect in an AC bulb, since
the leading order effect cancels.

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.

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.

The tungsten in the lamp is run within a few hundred kelvins of its
melting point, so it's always in the fully annealed state, which ought
to mean that there are no metal fatigue mechanisms operating, just
material migration due to sublimation.

Yep, but different failure mode. When the extremely thin layer of
tungsten plating evaporates, the light becomes dimmer. Below some
brightness level, it is considered to have failed. However, most such
tungsten coated filaments fail due to corrosion of the base steel
alloy wire which is exposed to the internal gases inside the bulb
after the tungsten evaporates. The gases (mostly nitrogen and some
argon) are inert, but there's a little water vapor outgassing from
heating the glass envelope, which eventually corrodes the filament.
Other failure modes are hot spots and notches caused by manufacturing
variations and tungsten evaporation.

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

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.

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 net
http://electrooptical.net

 

[Jeff Liebermann]

On Thu, 04 Oct 2012 10:03:21 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

On 10/03/2012 09:41 PM, Jeff Liebermann wrote:
On Wed, 03 Oct 2012 10:32:57 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> 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/MC3544HPX_Catalog_2_11_09.pdf
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_filament_evaporation>
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 jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Jeff Liebermann]

On Wed, 3 Oct 2012 10:34:04 +0000 (UTC), "Geoffrey S. Mendelson"
<gsm@mendelson.com> wrote:

Tom Biasi wrote:
Not so. With mechanical devices, regular moderate use provides a longer
useful lifetime than using the device only rarely.


I don't agree but will say no more.

Laser printers. I have given away for parts several laser printers because
they sat unused 99% of the time, and started to jam when I printed the
one or two pages a month I needed them for.

I've seen flat spots on laser printers. However, just running a few
pages through the printer usually returns them to normal. If not, use
some rubber roller restorer to soften the rubber.
<http://www.fixyourownprinter.com/specials/misc/all/S03>

In my experience, many printer jams are caused by paper slippage on
the rollers. Usually, it's the white paper dust that causes slippage,
but it can easily be household dust accumulated over the time the
printer was idle. Maybe hitting the printer with a compressed air
blast before operating might help.

Another slippage problem is when the rubber surface becomes glazed or
polished. The rubber roller restorer will take the surface gloss off
the rollers, and improve the traction, but if there's any rubber wear,
the roller(s) should be replaced.

Not only did the rubber wheels dry out and lose their ability to grab paper,
they flatten where they are pressed against something.

I have a perfectly good Samsung laser printer in that condition now.

Ugh. I don't have much nice to say about Samsung printers. They're
cheap, function adequately, use overpriced toner carts, and don't last
very long. I've never really done an autopsy to isolate a culprit.
The usual end of life symptoms are either paper jams or flimsy broken
plastic parts.

My choices are to once a week clean out a jam, and clean the feed roller;
print something everyday (a waste of paper); spend $15 for a new roller
(including postage) and an hour to install it; or wait for a sale
(every 2-3 months) and buy a newer faster, higher resolution model with a
2,000 page toner cartridge included for less than the cost of a full load toner.

Chuckle. Yeah, that's about it. Next purchase, I suggest HP LaserJet
printers. They have their own collection of problems, but parts and
refills are commonly available and cheap. The printer cannibals sell
used parts and assemblies fairly cheap on eBay. Also, expertise is
more easily found:
<http://www.fixyourownprinter.com>
My favorite printer of the week is the HP 2300DN or DTN at between $90
to $220 used depending on condition and options. Favorite feature is
double sided (duplex) printing.

Geoff.

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

 

[Jeff Liebermann]

On Wed, 03 Oct 2012 19:42:21 -0400, "krw@att.bizzzzzzzzzzzz"
<krw@att.bizzzzzzzzzzzz> wrote:

My 39YO HP45 still works but the power switch is too flaky to be usable.

I collect old HP LED type calculators. The HP 45 is well worth fixing
and using.

The switches tend to fail due to dirt accumulation and/or wearing a
grove into the PCB contact area from overuse. I've repaired both
problems.
<http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv018.cgi?read=131014>
This is the dirt problem:
<http://i45.photobucket.com/albums/f96/geoff_q/gunk.jpg>
I couldn't find a photo of a grove worn in the contacts. I've been
quite successful with just cleaning the switch area. I've also
repaired missing gold problems with gold leaf. It was difficult,
required a microscope, a steady hand, no air movement, and
considerable patience.

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

 

[Phil Hobbs]

On 10/04/2012 02:57 PM, George Herold wrote:

On Oct 4, 12:43 pm, Jeff Liebermann<je...@cruzio.com> wrote:
On Thu, 04 Oct 2012 10:03:21 -0400, Phil Hobbs





pcdhSpamMeSensel...@electrooptical.net> wrote:
On 10/03/2012 09:41 PM, Jeff Liebermann wrote:
On Wed, 03 Oct 2012 10:32:57 -0400, Phil Hobbs
pcdhSpamMeSensel...@electrooptical.net> 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 je...@cruzio.com
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 net
http://electrooptical.net

 

[George Herold]

On Oct 4, 12:43 pm, Jeff Liebermann <je...@cruzio.com> wrote:

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





pcdhSpamMeSensel...@electrooptical.net> wrote:
On 10/03/2012 09:41 PM, Jeff Liebermann wrote:
On Wed, 03 Oct 2012 10:32:57 -0400, Phil Hobbs
pcdhSpamMeSensel...@electrooptical.net>  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     je...@cruzio.com
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.

 

[Jeff Liebermann]

On Thu, 4 Oct 2012 11:57:21 -0700 (PDT), George Herold
<gherold@teachspin.com> wrote:

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

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

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

 

[Tom Biasi]

On 10/3/2012 2:01 AM, MikeS wrote:

Using anything shortens it's working life.

Seems to go against the whole ethos of exercising. Never get out of bed and
live forever ...


If you were an android that may be true.

 

[Geoffrey S. Mendelson]

Jeff Liebermann wrote:

refills are commonly available and cheap. The printer cannibals sell
used parts and assemblies fairly cheap on eBay. Also, expertise is
more easily found:
http://www.fixyourownprinter.com
My favorite printer of the week is the HP 2300DN or DTN at between $90
to $220 used depending on condition and options. Favorite feature is
double sided (duplex) printing.

Problem with that is my location. Shipping anything from anywhere except
China is too expensive to make it worth while. A $10 (postage included)
Samsung feed roller is worth buying, a part that does not fit in an envelope
and has to go in a USPS box costs 1/2 to 1/3 the cost of a cheap Samsung
printer. UPS/DHL/FDEDX double or tripple that price.

Also to be honest, the loss/theft rate from the US is too high to buy
from unless it is via PayPal and eBay.

Geoff.
--
Geoffrey S. Mendelson, N3OWJ/4X1GM/KBUH7245/KBUW5379
"Owning a smartphone: Technology's equivalent to learning to play
chopsticks on the piano as a child and thinking you're a musician."
(sent to me by a friend)

 

[Dave Plowman (News)]

In article <slrnk6ror4.jds.gsm@cable.mendelson.com>,
Geoffrey S. Mendelson <gsm@mendelson.com> wrote:

Problem with that is my location. Shipping anything from anywhere except
China is too expensive to make it worth while. A $10 (postage included)
Samsung feed roller is worth buying, a part that does not fit in an
envelope and has to go in a USPS box costs 1/2 to 1/3 the cost of a
cheap Samsung printer. UPS/DHL/FDEDX double or tripple that price.

Also to be honest, the loss/theft rate from the US is too high to buy
from unless it is via PayPal and eBay.

Couple of years back I needed a new element for my Pace SX80 desolder
iron. Not one to be had in the UK. Got one from Pace US direct at not a
bad price - but they charged 40 gbp for P&P by courier - wouldn't send it
by post. So the delivered price was considerably more than the delivered
price from a UK supplier. If it had been coming from Hong Kong or China,
would have been less than half the price and free postage...

There's lots of stuff I'd buy from the US if they would sort out their
postal service. I get the impression as much is stolen as delivered.

--
*Two wrongs are only the beginning *

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

 

[Jeff Liebermann]

On Tue, 2 Oct 2012 22:21:26 +0100, "jim stone"
<tgh6h56nzh@mail.invalid> 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 jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[George Herold]

On Oct 4, 4:28 pm, Phil Hobbs <pcdhSpamMeSensel...@electrooptical.net>
wrote:

On 10/04/2012 02:57 PM, George Herold wrote:





On Oct 4, 12:43 pm, Jeff Liebermann<je...@cruzio.com>  wrote:
On Thu, 04 Oct 2012 10:03:21 -0400, Phil Hobbs

pcdhSpamMeSensel...@electrooptical.net>  wrote:
On 10/03/2012 09:41 PM, Jeff Liebermann wrote:
On Wed, 03 Oct 2012 10:32:57 -0400, Phil Hobbs
pcdhSpamMeSensel...@electrooptical.net>    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     je...@cruzio.com
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 itďż˝s turning on.)  But still this means
that turning on the bulb causes the thin region to become a bit
thinner.

And thatďż˝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.

 

[George Herold]

On Oct 4, 5:05 pm, Jeff Liebermann <je...@cruzio.com> wrote:

On Thu, 4 Oct 2012 11:57:21 -0700 (PDT), George Herold

gher...@teachspin.com> 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     je...@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

 

[Roderick Stewart]

In article <de99517e-e5e1-4f9d-91e0-
412ab3171a05@o8g2000yqm.googlegroups.com>, 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.
--

 

[Jeff Liebermann]

On Fri, 5 Oct 2012 07:43:56 -0700 (PDT), George Herold
<gherold@teachspin.com> 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 jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Phil Hobbs]

On 10/05/2012 06:20 AM, Roderick Stewart wrote:

In article<de99517e-e5e1-4f9d-91e0-
412ab3171a05@o8g2000yqm.googlegroups.com>, 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