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From: whit3rd on 15 May 2010 20:10
On May 14, 2:11 pm, Merciadri Luca <merciadril...(a)gmail.com> wrote:

> I would like to know, for some devices that I have (e.g. PDA,
> calculator, etc.), the maximum magnetic field they can cope with. How
> can I know

Good question: the easy answer is, they have to tolerate 0.5 gauss
(which is kinda the background field on much of Terra). Slight
exception: CRT displays are commonly tuned up aimed in
magnetic N direction, and DO change according to orientation.

Static B fields also disable photomultipliers and, if strong enough,
saturate magnetic elements (causing distortion of signals, or can
pop fuses attached to power inductors). Dynamic B fields cause
EMFs in most wiring (hopefully, though, not coaxial cables). I've
even heard of transient B fields damaging woodwork, but that was
a big fast current switch that made cables jump. The folk who shrink
pennies are demonstrating the structural failure of metal disks with
high B field transients...
From: Merciadri Luca on 16 May 2010 05:55
On May 16, 2:10 am, whit3rd <whit...(a)gmail.com> wrote:
> On May 14, 2:11 pm, Merciadri Luca <merciadril...(a)gmail.com> wrote:
>
> > I would like to know, for some devices that I have (e.g. PDA,
> > calculator, etc.), the maximum magnetic field they can cope with. How
> > can I know
>
> Good question:  the easy answer is, they have to tolerate 0.5 gauss
> (which is kinda the background field on much of Terra).   Slight
> exception: CRT displays are commonly tuned up aimed in
> magnetic N direction, and DO change according to orientation.
>
> Static B fields also disable photomultipliers and, if strong enough,
> saturate magnetic elements (causing distortion of signals, or can
> pop fuses attached to power inductors).   Dynamic B fields cause
> EMFs in most wiring (hopefully, though, not coaxial cables).  I've
> even heard of transient B fields damaging woodwork, but that was
> a big fast current switch that made cables jump.   The folk who shrink
> pennies are demonstrating the structural failure of metal disks with
> high B field transients...

Thanks.
From: BobG on 16 May 2010 15:01
Go down to T-mobile and get an Android phone. They have a 3 axis
magnetometer so they can find north no matter which way the phone is
oriented, and show the map right side up. The specs say it is
sensitive to 7000 micro teslas or something. I cant find the specsheet
right now darnit. I wonder if you could put the phone in an mri turned
off, shoot it, take it out and have it work?
From: BobG on 16 May 2010 15:09
Mister Luca... Welcome to the sci.electronics.basics Club of The
Initiated who have been cursed by good ol Phil from Down Under. He has
probably singlehandedly done more damage to Austrailian International
Relations with engineers worldwide than a whole cruise ship full of
loud rude Yanks with flowered shirts. Man am I glad he aint an
American. I have enough of a problem defending capitalism to domestic
socialists without having to defend bipolar sociopaths that are rude
to perfectly polite strangers. I bet the next message is him telling
me I have symptoms of Autistic Spectrum Disorder...
From: Jamie on 16 May 2010 15:50
BobG wrote:

> Mister Luca... Welcome to the sci.electronics.basics Club of The
> Initiated who have been cursed by good ol Phil from Down Under. He has
> probably singlehandedly done more damage to Austrailian International
> Relations with engineers worldwide than a whole cruise ship full of
> loud rude Yanks with flowered shirts. Man am I glad he aint an
> American. I have enough of a problem defending capitalism to domestic
> socialists without having to defend bipolar sociopaths that are rude
> to perfectly polite strangers. I bet the next message is him telling
> me I have symptoms of Autistic Spectrum Disorder...
What's wrong with noisy yanks and flowered shirts?

Jamie.

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