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Units of 1/Farads and 1/Henries?

J

Joel Kolstad

Jan 1, 1970
0
Just curious... the untis of the inverse of an Ohm are a Mho (cute). Is
there an equivalent for the inverse of Farads and Henries? I realize that
most of the time you're after the impedance broken into the resistance and
reactance (units: ohms) or the admittance broken into conductance and
susceptance (unit: mhos), but I figure there's a good chance someone named
1/Farads and 1/Henries at some point in time.

---Joel Kolstad
 
R

Rich Grise

Jan 1, 1970
0
Just curious... the untis of the inverse of an Ohm are a Mho (cute). Is
there an equivalent for the inverse of Farads and Henries? I realize that
most of the time you're after the impedance broken into the resistance and
reactance (units: ohms) or the admittance broken into conductance and
susceptance (unit: mhos), but I figure there's a good chance someone named
1/Farads and 1/Henries at some point in time.

What would they mean?

Thanks,
Rich
 
J

Joel Kolstad

Jan 1, 1970
0
Rich Grise said:
What would they mean?

Nothing physically, just an 'interim' unit if you want to talk about, say,
parallel inductors or series capacitances.

Apparently I'll just stick with F^-1 and H^-1...

---Joel
 
J

Joel Kolstad

Jan 1, 1970
0
Roger Johansson said:
No, it is called Siemens. Mho does not exist in the modern world.

But writing an upside-down Omega is so much fun!

Do you have anything that suggests Mho is actually deprecated rather than
simpler synonymous with Siemens?

---Joel
 
R

Roger Johansson

Jan 1, 1970
0
Joel Kolstad said:
Do you have anything that suggests Mho is actually deprecated rather
than simpler synonymous with Siemens?

The SI system is the international scientific and technical standard in
the modern world. There is no Mho in that system.

We should avoid all older or regional units and use the SI system to
simplify understanding and education in a global perspective.
 
J

Joel Kolstad

Jan 1, 1970
0
Roger Johansson said:
We should avoid all older or regional units and use the SI system to
simplify understanding and education in a global perspective.

Fair enough...

It is amsuing that the English have switched to SI whereas the US hasn't
yet! ;-)
 
C

Clarence

Jan 1, 1970
0
Joel Kolstad said:
Fair enough...

It is amsuing that the English have switched to SI whereas the US hasn't
yet! ;-)

An Engineer worth his salt should be able to work in any system presented.
 
J

Joe McElvenney

Jan 1, 1970
0
Hi,
Just curious... the untis of the inverse of an Ohm are a Mho (cute). Is
there an equivalent for the inverse of Farads and Henries? I realize that
most of the time you're after the impedance broken into the resistance and
reactance (units: ohms) or the admittance broken into conductance and
susceptance (unit: mhos), but I figure there's a good chance someone named
1/Farads and 1/Henries at some point in time.


The reciprocal of 'Capacitance' is 'Elastance' which comes
from the similarity to the spring constant. It is measured in
'Darafs' would you believe.

The reciprocal of 'Inductance' is sometimes given as 'Reluctance'
but you have to do a dimensional hand-stand to accept it.


Cheers - Joe
 
J

Joel Kolstad

Jan 1, 1970
0
Clarence said:
An Engineer worth his salt should be able to work in any system presented.

True, but statistically speaking there are going to be more mistakes when
engineers have to work in multiple systems. There are good examples out
there of very large dollar systems such as satellites failing due to this
problem.
 
D

Don Kelly

Jan 1, 1970
0
Joel Kolstad said:
Just curious... the untis of the inverse of an Ohm are a Mho (cute). Is
there an equivalent for the inverse of Farads and Henries? I realize that
most of the time you're after the impedance broken into the resistance and
reactance (units: ohms) or the admittance broken into conductance and
susceptance (unit: mhos), but I figure there's a good chance someone named
1/Farads and 1/Henries at some point in time.

---Joel Kolstad

Not that I know of. However, the 1/Ohm, or what was called a "mho" is now
officially called a "Siemen". It is possible that someone, somewhere uses a
Daraf or a Yrneh but why?
Susceptance (-1/2*pi*f*L or 2*pi*f*C) is in Siemens. (mhos If you don't want
to change habits)
 
D

Don Kelly

Jan 1, 1970
0
Joel Kolstad said:
Fair enough...

It is amsuing that the English have switched to SI whereas the US hasn't
yet! ;-)
Are your texts all out of date? The Siemen is used in US engineering texts
and literature.
 
J

Joel Kolstad

Jan 1, 1970
0
Don Kelly said:
Are your texts all out of date? The Siemen is used in US engineering
texts
and literature.

I meant in general... when you go to the store to buy furniture in the U.S.,
the dimensions are in inches/feet/etc.

On the technical side, if you look at magnetics manufacturers, many of them
still use slightly non-SI units... it's apparently a slow industry to
change. (I was at a seminar once where the speaker mentioned, "You have to
realize, they're basically just selling you a bunch of processed dirt..."
:) )

---Joel
 
D

Don Kelly

Jan 1, 1970
0
Joel Kolstad said:
I meant in general... when you go to the store to buy furniture in the U.S.,
the dimensions are in inches/feet/etc.

On the technical side, if you look at magnetics manufacturers, many of them
still use slightly non-SI units... it's apparently a slow industry to
change. (I was at a seminar once where the speaker mentioned, "You have to
realize, they're basically just selling you a bunch of processed dirt..."
:) )

---Joel
Sure and I calculate my gas consumption in miles per gallon- translating
from liters/100km. even though I have been using metric units for 50 years
and SI since it came into official play. My tape measure still is in inches
and feet and I am in an officially SI country next door north from you.
However, dealing with Gauss instead of Tesla is not a problem- I just
convert and carry on. Lines/sq. inch -oops-what is the bugger factor?
At least we don't play around with abvolts, abamperes or statvolts and
statamperes. :)
 
B

Brian Oakley

Jan 1, 1970
0
Roger Johansson said:
The SI system is the international scientific and technical standard in
the modern world. There is no Mho in that system.

We should avoid all older or regional units and use the SI system to
simplify understanding and education in a global perspective.

another way to conform our government to the rest of the world
 
D

Don Kelly

Jan 1, 1970
0
Brian Oakley said:
another way to conform our government to the rest of the world
What has the government to do with it. It makes good sense. Good sense and
government rarely go together.
 
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