an observation on Ohms Law

[johnkramer]

curious, at what point in time did E transpose to V?

I saw E expressed as V in Ohms law recently and I thought it was a mistake. But when I googled I came across a few sites that express it like this.

I learned that voltage was expressed as E

E= Voltage or (E)nergy
I= Current or (I)ntensity
R= Resistance (obvious)
P= Power (obvious)

P=IE and E=IR or Pie and Eir, Pioneer, get it? snicker snicker (yes my electronics teacher was a super dork). Actually he was smart, he pointed out that its important to not look at E as voltage per se, but as energy, sighting a cross reference to water and air flow. His point was to teach us not to think of Ohms Law as an "electrical" formula, but as a physical law of nature.

I know its just academic, but this was one of those tiny things that helped me to think independently.

[Frank Berry]

"curious, at what point in time did E transpose to V?"

Thanks for your observation. I have wondered the same.
By the way ... we must have studied under the same Teacher!

[millwood]

as I recall, E usually means "potential" (what it is relative to, I don't recall). so voltage between two points is really the difference between the two points' potential.

or V = delta E.

Potential itself will not cause electrons to flow. But he difference in potential will.

[pinkmouse]

Moved to EE, 'cos this is on topic for the site!

[Christer]

Originally posted by millwood
as I recall, E usually means "potential" (what it is relative to, I don't recall). so voltage between two points is really the difference between the two points' potential.

or V = delta E.

Potential itself will not cause electrons to flow. But he difference in potential will.

Interestingly, in some countries like Sweden and Germany,
we use U for voltage and V for potential. To add to the
confusion, E is often used for the voltage of a voltage source.

Just don't ask me where the U comes from originally, but I
suspect it has its origin in Germany.

[Workhorse]

Originally posted by Christer



Interestingly, in some countries like Sweden and Germany,
we use U for voltage and V for potential. To add to the
confusion, E is often used for the voltage of a voltage source.

Just don't ask me where the U comes from originally, but I
suspect it has its origin in Germany.

YES, thats rite 'U' is incarnation of German Engineering.

Compliments to Christer
ampman

[li_gangyi]

here in SG for physics class...we have this crappy ohms law wheel thingy...basically it's based om P=VI and V=IR...we dp use E and V interchangeably though...but for clarity...V is used most of the time during theory and test papers...wonder why the E and V thingy...perhaps originally it was like Current...represented by I and has a unit of A...so Potential Difference would be represented by E and measured in V...I dunno..just speculating...

[rif]

I believe it's a difference between physicist's and engineer's conventions is all. Same thing with imaginary numbers: physicists use i, engineer's use j but they're both sqrt(-1).

What else is different -- hmm...tough to remember so far back to university.

**Maybe vector notation--putting the arrow above or below the variable?

**mhos vs Siemens?

[Pjotr]

**mhos vs Siemens? [/B]

Hi,

Mho is the reverse of “ohm”, so multiple of them should be smho ???

If I remember well E is used in electrostatics to denote the potential of an electric field and it is used also for electromagnetic emission (i.e antennas): E-field an H-field vectors.

Have a look here:

http://physics.nist.gov/cuu/Units/

and:

http://physics.nist.gov/cuu/Units/units.html

Cheers

[Svante]

In Sweden we say U=R*I