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Author Topic: Ohm's Law  (Read 13690 times)
AA4PB
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« Reply #30 on: May 18, 2013, 05:29:34 PM »

E = "Electromotive force" which = "difference of potential" which is measured in "Volts".  Wink

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K8AXW
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« Reply #31 on: May 18, 2013, 09:27:37 PM »

Randy:  That's the way I learned it too but also learned one for mixed company:

Bad Boys Ruin Our Grass But Violets Grow Wild.

Al - K8AXW
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KE3WD
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« Reply #32 on: May 19, 2013, 06:29:57 AM »

Both of ya give the PC version from the way we learned it back in the fifities...


*grin*


It may have been UN P.C. -- but darn near every class member *remembered* the mnemonic from the first time it was heard! 

And, at that time, I was the only black member of the class. 

So what?  The class was about Electronics, not social engineering...



73
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WB2EOD
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« Reply #33 on: May 19, 2013, 12:56:24 PM »


better be right or your great big venture goes wrong
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W0DV
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« Reply #34 on: May 19, 2013, 08:27:01 PM »

E = "Electromotive force" which = "difference of potential" which is measured in "Volts".  Wink



An intelligent, thoughtful answer!

Thank You,

Dave
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WB6DGN
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« Reply #35 on: May 22, 2013, 10:13:52 PM »

Randy:  That's the way I learned it too but also learned one for mixed company:
Bad Boys Ruin Our Grass But Violets Grow Wild.
Al - K8AXW

You forgot "yellow".  You'd need to make it "bad boys ruin our young grass....." or yellow grass or ??

Tom
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KE3WD
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« Reply #36 on: May 23, 2013, 06:46:43 AM »


Way back in school, in the early 60's, they were still teaching the old politically incorrect mnemonic. 

Say what you will, but I don't think there was a single student in that class who did not "get it" the first shot, and retained it for life. 

Being the only African American in that class, it didn't bother me at all.  I was there to learn the Art of Electronics, pursuing my calling and love of the craft. 

I remember joking with the old instructor, you know, the guy with the buzz cut, glasses and pocket protector fulla pens and pencils, when leaving the class that day. 

He asked me what I was going to do that evening and I told him, "I'll be looking for that gal named Violet!" 

The one that gives WILLINGLY! 

"Be careful," he said. 

"And discreet!" I added...


73
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VA1CQ
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« Reply #37 on: May 25, 2013, 12:37:02 PM »

Never heard any of the above PC versions. Perhaps we were less PC in Canada. Our high school instructor taught us about the willing young Violet (though there happened not to be any women in our class) and I never forgot the colours/values.
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K8AXW
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« Reply #38 on: May 25, 2013, 08:03:49 PM »

DGN:  Yup..... forgot the Young Grass..... Like WD I first learned the "other" way, which I never forgot.  It's when we start throwing the PC sh.t in the game do I start forgetting things like Young!
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KE3WD
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« Reply #39 on: May 26, 2013, 06:50:16 AM »

The mnemonic thing was so long ago, it seems. 

Don't need it anymore really.

Like CW. 

"Here Comes the Queen" or "Diddy-Dum-Dum-Diddy"

At some point, the repetition of use kicks the little gray cells in and there is no longer any need for "decoding" or translating things in the concious mind. 

Years of dealing with the components, day in and day out, the familiarity breeds the contempt of knowing the resistor value on sight for many of the more common values, and also being able to rapidly nail the less common ones. 

Just like the day you suddenly realize that you are copying the CW ragchew entirely in your head, as whole words rather than one character at a time and there is no need for the pencil anymore. 


73
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KB3HG
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« Reply #40 on: May 30, 2013, 11:02:16 AM »

Had a Instructor whom had Chaplin bars on after his tests. Bill Dykes W3FRC, his 40's version for the code.....Bad Boys Romance Our Young Girls Behind Victory Garden Walls. nothing other the colors for tolerance  that I can remember now.
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AA4HA
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« Reply #41 on: May 30, 2013, 01:46:31 PM »

This entire argument about Ohm's law was started by some guy named Mho who was much more conductive to the idea, Ohm just kept resisting.

The old school curmudgeons got involved, those guys named Mattheisen and Jacobi but they could not remain friends. Mattheisen called Jacobi a "dirty yellow copper", Jacobi responded that at least he was not quite so ductile.

SI came on board and said that if you do not behave I will put you in different units. Eventually Mho changed his name to Siemens.
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Ms. Tisha Hayes, AA4HA
Lookout Mountain, Alabama
N3DF
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Posts: 252




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« Reply #42 on: May 30, 2013, 05:44:36 PM »

This entire argument about Ohm's law was started by some guy named Mho who was much more conductive to the idea, Ohm just kept resisting.

The old school curmudgeons got involved, those guys named Mattheisen and Jacobi but they could not remain friends. Mattheisen called Jacobi a "dirty yellow copper", Jacobi responded that at least he was not quite so ductile.

SI came on board and said that if you do not behave I will put you in different units. Eventually Mho changed his name to Siemens.

The only question I missed on my Novice test in 1965 was "The Mho is the unit of _________________."
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Neil N3DF
KE3WD
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« Reply #43 on: May 31, 2013, 05:41:25 AM »

Mho, Larry and Curly...
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W1BVV
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« Reply #44 on: June 10, 2013, 08:34:00 AM »

At the risk of beating a dead horse and being too pedantic (I anm a Physics teacher and an Electrical Engineer), the E in older references to Ohm's law (I learned E=IR) also, came from the concept of electromotive force, or EMF sometimes written as a script E.  The electromotive force is actually the electrical potential created by a voltage source such as a chemical cells in a battery.  V, or Voltage or more accurately voltage drop or potential drop is a unit that is measured from a node to a reference (usually but not always) ground or across the two terminals of a resistor, or a battery.

Thus the voltage (V) of a battery is the voltage drop across the battery which would equal EMF (of the cell)- I*R where R is the internal resistance of the battery and I is the current being drawn from the battery.  Vb = EMF-IR.

So V, and what used to be E, and is now scriptE or EMF are very different.

There technically is no unit E, although E is the symbol for Electric Field.

Sorry,

W1BVV, Dave

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