r we able to male precise 1ohm resistance

[[email protected]]

how can we make it if we wann i realy wann to konow abt it

 

[Uwe Bonnes]

how can we make it if we wann i realy wann to konow abt it

If you can't write a sensible question, I guess the same applies for more
things :-(

 

[John Fields]

how can we make it if we wann i realy wann to konow abt it

 

[MassiveProng]

He must be all doped up. Still, he seems smarter than some of the
fare that has passed through the group in the last month.

 

[default]

how can we make it if we wann i realy wann to konow abt it

Mr. Cool Groper

Learn to type real words, get a real news reader, post to a basic
group if you have a basic question, learn how Usenet works and follow
the conventions.

DITCH GOOGLE Google is not your friend; or ours.

Sorry
That's probably way over your head. Try this:

Lern t ype wrds get a nwsrdr post t a basik grp w/ basik ques lern
usenet don use ggle

 

[[email protected]]

I hate to admit it, but John Fields is right, as far as he goes.

If you want a precise and stable 1.00 ohm reistance, it helps to use
manganin or constantan wire. Both alloys have a very low temperature
coefficient of resistance at room temperature

http://www.goodfellow.com/csp/active/static/A/Manganin_-_Resistance_Alloy.HTML

http://en.wikipedia.org/wiki/Constantan

http://www.goodfellow.com/csp/active/STATIC/A/Constantan_-_Resistance_Alloy.HTML

For low resistance resistors, it is a good idea to use the wire to
make a Kelvin four-terminal resistor - the current through the
resistor flows through two of the leads, and you measure the voltage
drop across the 1.00 ohm length of wire through two other leads. See
page 5 of the appication note below

http://www.welwyn-tt.com/pdf/application_notes/Current-Sense_AN.pdf

 

[Brandon D Cartwright]

He must be all doped up. Still, he seems smarter than some of the
fare that has passed through the group in the last month.

Is there absolutely no thread or subject you wont try to hijack with
your abuse and nonsense?

X-Complaints-To: [email protected]

 

[Tom Bruhns]

how can we make it if we wann i realy wann to konow abt it

That depends on what you have to start with. Can you accurately
measure voltage and current? Do you have an accurately-known
resistance of some other value already? Do you have a way to control
the temperature of the resistor after you make it, so that thermal
drifts and thermal emfs won't destroy its accuracy? What materials do
you have to make it from? Just how accurate do you want it?

The people who DO know how to make very stable, accurate resistors
understand not only the theory but the art: they understand how to
process the materials so that, for example, stresses don't destroy the
accuracy.

Do a Google search for things like "history of resistance standards"
and you'll find some info on it. The paper at
http://nvl.nist.gov/pub/nistpubs/sp958-lide/html/063-065.html about
resistance standards is pretty interesting; the NBS (now NIST)
resistance standard from about 1931 up until 1990 was a set of 1-ohm
resistors that are still in use today as transfer standards.

Cheers,
Tom

 

[martin griffith]

On 18 Apr 2007 04:06:50 -0700, in sci.electronics.design

how can we make it if we wann i realy wann to konow abt it

read this
http://www.guardian.co.uk/styleguide/page/0,,184844,00.html


martin