magnetic field

[Art]

Gov, may be a lot less expense just to buy the flippin things. Google for
magnet supplies, surely there are global manufacturers ready to sell you as
many as you need for your needs.
"dan" <notme@privacy.net> wrote in message
news:43ffc588.15827204@news20.forteinc.com...

What's that Lassie? You say that siliconmike fell down the old
sci.electronics.misc mine and will die if we don't mount a rescue by
26 May 2005 03:13:16 -0700:

I would appreciate if anyone can advise as to how to make magnets. I
have an electronic engineering background, but have never done this
before. I want to make tiny magnets, say size of 4mm x 4mm or 6mm x
6mm, of the power of 4000 to 5000 Gauss (higher the better)..

What material should I use ?
What coating should I do on that material for corrosion protection ?
What would be the thickness of the coating ?
Should I do coating before / after magnetizing ?
What would be the coil / dc power setup ?
How do I measure the strength afterwards ?

Any advise would be great.

Thanks
Mike
http://www.kjmagnetics.com/
--

Dan

 

Charlie Edmondson wrote:

But, the only way to really tell which outlet is first is to pull each
one out, and buzz out each side. Takes a while, but is the only sure
way to find out. Unless, of course, you took pictures of the wiring
before they put up the sheetrock!

Well, if you had a fast scope, and a pulse generator, and pulled the
end out of the breaker box and drove it like an RF transmission line,
you might learn something by plugging a simple "nightlight" load into
each outlet while watching the scope.

If it's on the first floor and the basement is unfinished, you might be
able to get a good idea just by looking up.

 

[Joe Soap]

In response to what <cs_posting@hotmail.com> posted in
news:1140978884.155392.113690@v46g2000cwv.googlegroups.com:

Well, if you had a fast scope, and a pulse generator, and pulled the
end out of the breaker box and drove it like an RF transmission line,
you might learn something by plugging a simple "nightlight" load into
each outlet while watching the scope.

Or maybe use a Time Domain Reflectometer.

--
Joe Soap.
JUNK is stuff that you keep for 20 years,
then throw away a week before you need it.

 

On 26 Feb 2006 10:34:44 -0800, cs_posting@hotmail.com wrote:

Charlie Edmondson wrote:

But, the only way to really tell which outlet is first is to pull each
one out, and buzz out each side. Takes a while, but is the only sure
way to find out. Unless, of course, you took pictures of the wiring
before they put up the sheetrock!

Well, if you had a fast scope, and a pulse generator, and pulled the
end out of the breaker box and drove it like an RF transmission line,
you might learn something by plugging a simple "nightlight" load into
each outlet while watching the scope.

If it's on the first floor and the basement is unfinished, you might be
able to get a good idea just by looking up.

Connect the recepticle to your testicle and you will know !!!!

 

[cbm5]

Bob Myers wrote:

testing_h@yahoo.com> wrote in message
news:1140563411.180459.6820@g47g2000cwa.googlegroups.com...
MW oven, 1 second, HIGH


In that case, I strongly suspect that this "nuking"
did absolutely nothing significant, and any change
you saw in the battery's behavior was
coincidental.

Bob M.

Hmm, you may be right, depending on the shape of the battery the RF may
not have penetrated very far. Most likely would stay entirely on the
outside of the metal can. But I guess beaming a few hundred Watts of RF
into an electrical device MIGHT do something, I'd be tempted to try it
if I had a dead NiMH and a microwave I planned to throw away, and a lot
of bricks to pile around it.

 

[Anthony Fremont]

"maxfoo" <maxfoo@punkass.com> wrote in message
news:bn2m0254unn8lia447g35gif0ke18iqcf0@4ax.com...

On 5 Mar 2006 03:42:20 -0800, cbarn24050@aol.com wrote:

good grief 1600+ bytes for 2 little delays! if i'de written that I
wouldn't ever publish it. You should be able to get the guts of this
down to 50 bytes at most maybe half that with some effort.

LMAO, this is what happens when software people play with hardware,
snip
cough!!

If you liked that, you should see the mess that hardware experts make
when they try to write software. ;-)

 

[Frank Bemelman]

"BrunoG" <noreply@micro-examples.com> schreef in bericht
news:440b8053$0$20177$8fcfb975@news.wanadoo.fr...

cbarn24050@aol.com> a écrit dans le message de news:
1141601358.877866.257620@t39g2000cwt.googlegroups.com...


I dont have the spare time to write, compile and debug code just for
you. If you cant see how simple your code should have been then you
need to find another occupation.

Sure you will not have enough time, eternity will not be long enough to
rewrite this within 50 rom bytes.

This is probably what eats most of the 1676 bytes:

unsigned long d
d /= 1000 ; // divide by 1000 because
d /= (long)Clock_Khz() ; // clock frequency is known in Khz

And these lines only add a bit of convenience... would be nice
to see how many bytes you need without these lines.

--
Thanks, Frank.
(remove 'q' and '.invalid' when replying by email)

 

[BrunoG]

"Frank Bemelman" <f.bemelmanq@xs4all.invalid.nl> a écrit dans le message de
news: 440c3b75$0$6581$e4fe514c@dreader30.news.xs4all.nl...

"BrunoG" <noreply@micro-examples.com> schreef in bericht
news:440b8053$0$20177$8fcfb975@news.wanadoo.fr...
cbarn24050@aol.com> a écrit dans le message de news:
1141601358.877866.257620@t39g2000cwt.googlegroups.com...


This is probably what eats most of the 1676 bytes:

unsigned long d
d /= 1000 ; // divide by 1000 because
d /= (long)Clock_Khz() ; // clock frequency is known in Khz

And these lines only add a bit of convenience... would be nice
to see how many bytes you need without these lines.

--

Yes sure, long div is costly, as well as struct members and arrays usage.
But the goal of this program is to show how to use interrupts, timers and
pointers in mikroC, not to have an optimization challenge.

A math trick to replace long type calculations would spare a few hundreds of
bytes, but the example would loose its clarity.

For those are interested by a high-level language optimization challenge
(basic or C) for pic microcontrolers, please see :
http://www.mikroe.com/forum/viewtopic.php?t=3363

Thanks
Bruno
http://www.micro-examples.com/public/microex-navig/doc/200-pic-microcontroller-examples.html

 

BrunoG wrote:

cbarn24050@aol.com> a écrit dans le message de news:
1141601358.877866.257620@t39g2000cwt.googlegroups.com...


I dont have the spare time to write, compile and debug code just for
you. If you cant see how simple your code should have been then you
need to find another occupation.

Sure you will not have enough time, eternity will not be long enough to
rewrite this within 50 rom bytes.

This example is written for 2 delays, but it can handle up to 255 delays
with the same rom size (1690 bytes) just changing the #define directive. I
added a comment in the source code to notice it to beginners, thanks.

Bruno
http://www.micro-examples.com/public/microex-navig/doc/099-timers-delays.html

I tell you what, you build me a website and i'll write some decent code
for yours.

 

[Frank Bemelman]

"BrunoG" <noreply@micro-examples.com> schreef in bericht
news:440c42dc$0$20160$8fcfb975@news.wanadoo.fr...

Yes sure, long div is costly, as well as struct members and arrays usage.
But the goal of this program is to show how to use interrupts, timers and
pointers in mikroC, not to have an optimization challenge.

A math trick to replace long type calculations would spare a few hundreds
of
bytes, but the example would loose its clarity.

Indeed. As an example it fits its purpose, and even for a real
application it's okay to use, if speed/space is not an issue.

--
Thanks, Frank.
(remove 'q' and '.invalid' when replying by email)

 

[John Popelish]

Anthony Fremont wrote:

If you liked that, you should see the mess that hardware experts make
when they try to write software. ;-)

Did that crack make you feel better about the difficulties you have
with hardware design?

 

[JeffM]

JeffM wrote:

There are norms for Usenet.
They are based on logic. Abide by them or expect to be called on it.
You need to follow the link and read it as well.

[D'oh. I cut & pasted a link other than what i intended.]
Cross-posting vs multi-posting:
http://groups.google.com/group/sci.electronics.basics/browse_frm/thread/7b7c0624331012bb/3958f18673b5f374?q=EVERY-group-*-*-*-*-*-*-*-*-appear+*-proper-answer-*-*-*-given+much-easier-*-*-*-*-what's-going-on+*-frowned-on+*-correcting+*-polite-*-mention-*-*-*-*-*-*-*+Just-because-*-*-*-*-*-*-*-*-does-not-mean-*-*-*-*-*-*+*-Followup-To-*+*-*-*-too-lazy-*-*-*-*-*-appropriate-*+*-*-_perfect_-*-*-*-*+*-*-*-*-two-groups-*-*-aren't-*-different
..
..
More links re: yyq787's other faux pas:
Do Not Ask for Email Responses on Usenet
http://groups.google.com/group/comp.lang.c++/browse_frm/thread/1be99848cdac854b/23b6f2c0225de6a2?q=If-you-haven't-got-the-time-*-*-to-read-the-newsgroup-*-*+*-benefit-other-readers+Do-not-ask-for-replies-by-email
http://groups.google.com/group/comp.databases.xbase.fox/browse_frm/thread/b6f19ec89732441d/a48102855e7eedb8?q=zzz+*-*-many-people-*-*-*+do-not-ask-*-*-email-*+defeats-the-purpose-of-the-newsgroup+asking-that-answers-be-emailed

and Frithiof puts a fine point on it:
http://groups.google.com/group/sci.electronics.design/browse_frm/thread/6bcb6a340e7366b9/59f2e5cd95f222ea?q=You-are-demanding-a-favour+*-*-*-your-time-is-worth-more-than-my-time+since-*-*-*-I-don't-read-this-newsgroup+phishing-for-email-adresses+zzz+*-*-*-if-you-would-e-mail-me-privately

 

[Anthony Fremont]

"John Popelish" wrote:

Anthony Fremont wrote:

If you liked that, you should see the mess that hardware experts
make
when they try to write software. ;-)

Did that crack make you feel better about the difficulties you have
with hardware design?

Given the commentary by cbarn24050 and maxfoo, I really don't consider
mine to qualify as a "crack". In fact, I think it to be quite
appropriate. At least I wasn't publicly ridiculing anyone.

 

[John Fields]

On Sun, 05 Mar 2006 12:01:58 -0500, J. Yazel <jyazel@ds.net> wrote:

I would like to find a schematic for a photocell feeding a schmidt
trigger (CMOS). This will input the light from a not-very-bright panel
lamp. It is also very slow speed (once-a-half-second).

---
Photovoltaic or photoresistive?

--
John Fields
Professional Circuit Designer

 

[Bob Myers]

"Ken" <leram@hotmail.com> wrote in message
news:IZpOf.8435$RM2.837216@news20.bellglobal.com...

You have just described an oscilator.... -)-)-)
try googling for that!!!

Actually its an oscillator-resonator,
cannot accomplish that with semiconductors

I sure hope you can...vacuum tubes are getting
harder to come by...

What exactly do you mean by an "oscillator-resonator"?
I looked over your schematic, and followed the
thread so far - but unless you really, really need to
have something that lets an LC tank "ring" all on its
on, and only kicks it again when the amplitude drops
down to some given point, this seems like an awful
lot of trouble to go to for a sine wave - you can do
THAT with a single transistor. What is it you're really
trying to do here?

Bob M.

 

[CWatters]

"siliconmike" <siliconmike@yahoo.com> wrote in message
news:1141443374.207913.43150@i40g2000cwc.googlegroups.com...

What certifications are mandatory for export to Europe (EU Countries)
for electronic products

- working on 12 volt car battery
- to be fitted inside an automobile
- related to autogas industry

Is CE required ?

It depends on the product. The CE mark mandatory for certain product
categories. The EC directives that detail which products will be on the web
somewhere. You can bet that anything electronic or child related must
comply.

The best advice is to ask one of the test houses for a short meeting to
discuss whats required. If they tell you that you need a particular test let
them give you a quote. You could also ask your customers... Many importers
will insist on a CE mark (even if not mandatory) as a way of mitigating any
liability they might have for a product that later turns out to have a
safety defect.

The CE mark generally indicates compliance will all EC standards that are
"relevant to that product". The problem is working out which EEC standards
are relevant. There are safety standards and EMC standards for example and
they are different for each product category. Even dynamite can carry a CE
mark. Ten years ago I worked on getting computers CE approved. Typically
back then our products needed to comply with EN55022 (EMC) and EN60950
(safety).

I once came accross a product that carried the CE mark but which clearly did
not comply. Contacted the firm and they admitted that they hadn't been able
to get their product to comply.... ironically the product was an expensive
bit of test equipment we were using to test our own product for CE
compliance. We got out money back.

 

[Ken]

What exactly do you mean by an "oscillator-resonator"?
I looked over your schematic, and followed the
thread so far - but unless you really, really need to
have something that lets an LC tank "ring" all on its
on, and only kicks it again when the amplitude drops
down to some given point, this seems like an awful
lot of trouble to go to for a sine wave - you can do
THAT with a single transistor. What is it you're really
trying to do here?

Bob M.

HI Bob,
Good question:
One of the thing I am trying to do well.
I can only explain well using an analogy.
You get on a swing set, you generate enough energy so that you start swing
(oscillating) everutime you reach a peak value, you give yourself (or a
friend..) a small push to keep going the same amplitude.BUT if you keep
giving the same push everytime with the same strenght you did the first one,
you will reach a point where you will no longer get to go any higher, or
simply break and fall. In an oscillating mechanical system when you reach
that point, the machine simply over heat or break down. This is what I want
to do electrically.

K

 

Anthony Fremont wrote:

"John Popelish" wrote:

Anthony Fremont wrote:

If you liked that, you should see the mess that hardware experts
make
when they try to write software. ;-)

Did that crack make you feel better about the difficulties you have
with hardware design?

Given the commentary by cbarn24050 and maxfoo, I really don't consider
mine to qualify as a "crack". In fact, I think it to be quite
appropriate. At least I wasn't publicly ridiculing anyone.

I wasn't trying to humiliate anyone either, he asked for comments. The
fact is needing multiple delays in a program is very commonplace and
it's normaly done with a few lines. What the author produced, however
well meaning, was just terrible. Thats not a problem for most people,
they just delete it in a heartbeat but a real beginner doesn't know any
better. Iv'e shown him how to do it, if he did it again that way he
would see for himself but his pride has been hurt, that was never my
intention, and so he's gone on the defensive. Your right about hardware
engineers messing up software but then again so do software engineers.

 

On 7 Mar 2006 05:40:22 -0800, "Silvester" <professor03@hotmail.com>
wrote:

Electronics is not my field, so I scoured the internet to find counter
circuits, but none of what I found really hits my exact needs.


I'm looking for a 2 or 3 digit counter that will count down from a
predefined number to zero - with a RESET switch to send the count back
to
the max number.

From what little I know of binary, I firgure I could use DIP switches
to set
the maximum number that the count starts at - a bank of 8 DIP switches
gives me a max of 255.

I need to count objects passing a certain point and I figured I use a
LED emitter and receiver pair, probably IR.


Can any one offer me some help?

Silvester

Do you want to build it or buy it? There's some simple to implement
IC's that contain presettable up/down counters used with BCD encoded
switches that contain most of what you need like the counters, digital
comparators, and latched display drivers. Plenty of "robot" sites on
the web with fairly easy to implement TV remote control style
circuitry for break beam or reflective detectors.

If you don't need a display and never intend to change the count it
may be less costly to build a discrete logic counter - but if it were
me, I'd use one of the Intersil counters.

Likewise you can get a hold of an industrial controls catalog and buy
a multifunction counter with display and optical sensor.

First option is inexpensive (in terms of money) time consuming,
educational and personally rewarding.

Second option is fast, expensive and easy. Check a Graingers catalog
for relatively cheap, ready made controls.

Build it for ~$50, buy it for ~$200

If you want to build it, look at
http://wwww.ges.cz/sheet/i/icm7217.pdf

The ICM7217 does it all in one IC and they show an LED example and LCD
adaptation.

I had an application that required a presettable count down timer to
switch a valve then start a second timer. (Intersil makes a modulus
60 counter as well as decade counters) Wiring and debugging took me
two days with the intersil parts, and another day to package it for
the lab to use. It was a breeze.

Doing the same thing with discrete logic elements would have taken me
a week or two.

I could send you schematics of my timers - but the data sheet gives
you what you need - my timer had a crystal controlled time base and
some logic circuits to stop one counter and start the second one.

Likewise I have some schematics of break beam and retro reflective
sensors.
--

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http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

 

[John Fields]

On 7 Mar 2006 05:40:22 -0800, "Silvester" <professor03@hotmail.com>
wrote:

Electronics is not my field, so I scoured the internet to find counter
circuits, but none of what I found really hits my exact needs.


I'm looking for a 2 or 3 digit counter that will count down from a
predefined number to zero - with a RESET switch to send the count back
to
the max number.

From what little I know of binary, I firgure I could use DIP switches
to set
the maximum number that the count starts at - a bank of 8 DIP switches
gives me a max of 255.

I need to count objects passing a certain point and I figured I use a
LED emitter and receiver pair, probably IR.


Can any one offer me some help?

---
If you only need to count and reset and don't want a numerical
display, you could use:

http://www.semiconductors.philips.com/acrobat_download/datasheets/74HC40103_3.pdf

with, perhaps, an LED to signal that the counter had reached zero?


--
John Fields
Professional Circuit Designer