Nice cheat sheet for the electrically challenged

I can never keep these rules straight in my head, so I was happy to
find this cheat sheet:

http://www.evparts.com/img/voltsampsohmwatts.PDF

2NO /* software guy */

On Mar 19, 10:21*pm, Tuno wrote:
I can never keep these rules straight in my head, so I was happy to
find this cheat sheet:

http://www.evparts.com/img/voltsampsohmwatts.PDF

2NO /* software guy */

Tuno,

I can still remember a little rule from my high school physics
teacher: V = IR (Volts = Amps x Ohms) or VIR as in "Veer" as in the
type of offense our pitiful high school football team ran, The "veer"
offense. Or something like that.

Ray Lovinggood
Carrboro, North Carolina, USA

In article Tuno writes:
I can never keep these rules straight in my head, so I was happy to
find this cheat sheet:

http://www.evparts.com/img/voltsampsohmwatts.PDF

2NO /* software guy */


Caution, the section for watts is only correct for DC or purely resistive
loads. For AC, it falls short if you are using something more complex than
an incandescent light bulb.

The 3 phase comment at the bottom assumes you are measuring the voltages
phase to phase, and that the load is purely resistive, and equally
distributed along the phases, which is probably an unusual condition.

Alan

On 20 Mar, 02:21, Tuno wrote:
I can never keep these rules straight in my head, so I was happy to
find this cheat sheet:

http://www.evparts.com/img/voltsampsohmwatts.PDF

There is one obvious typo: adding watts and ohms is meaningless (top
left).

And why the hell use E for volts? Not only would V be clearer, E is
also used as electric field strength (V/m)

Ian

"The Real Doctor" wrote in message
...
On 20 Mar, 02:21, Tuno wrote:

....Snip...

And why the hell use E for volts? Not only would V be clearer, E is
also used as electric field strength (V/m)

Ian

Maybe it was because E is what is used in his old Physics, and elementary
Electrical Engineering text books. (It is also the character use in FCC
Amateur Examinations.)

Wayne
Amateur Radio W7ADK
HP-14 "6F"
http://www.soaridaho.com/

"Wayne Paul" wrote in message
m...

...Snip...

And why the hell use E for volts? Not only would V be clearer, E is
also used as electric field strength (V/m)

Ian

Maybe it was because E is what is used in his old Physics, and elementary
Electrical Engineering text books. (It is also the character use in FCC
Amateur Examinations.)

Wayne
Amateur Radio W7ADK
HP-14 "6F"
http://www.soaridaho.com/


When I went through the US Navy's "Electronics Technician Class-A" school .
.. . lessee, that was 46 years ago (!!!), they told us the "E" was for
Electromotive Force.

bumper
Minden
zz
QV and MKIII

"bumper" wrote in message
...

"Wayne Paul" wrote in message
m...

...Snip...

And why the hell use E for volts? Not only would V be clearer, E is
also used as electric field strength (V/m)

Ian

Maybe it was because E is what is used in his old Physics, and elementary
Electrical Engineering text books. (It is also the character use in FCC
Amateur Examinations.)

Wayne
Amateur Radio W7ADK
HP-14 "6F"
http://www.soaridaho.com/


When I went through the US Navy's "Electronics Technician Class-A" school
. . . lessee, that was 46 years ago (!!!), they told us the "E" was for
Electromotive Force.

bumper

Other sources a
http://www.the12volt.com/ohm/ohmslaw.asp
http://www.allaboutcircuits.com/vol_1/chpt_2/1.html
http://www.angelfire.com/pa/baconbacon/page2.html
http://www.youtube.com/watch?v=_-jX3dezzMg

On 20 Mar, 14:40, "Wayne Paul" wrote:
"The Real Doctor" wrote in ...

And why the hell use E for volts? Not only would V be clearer, E is
also used as electric field strength (V/m)

Maybe it was because E is what is used in his old Physics, and elementary
Electrical Engineering text books. (It is also the character use in FCC
Amateur Examinations.)

Ah. Fair enough, in the latter case particularly. I've never seen E
used in that way myself, but if it's out there ...

Ian

Yes, in the upper left hand corner it should be Watts X Ohms (not
additive). Turn your head sideways. ;-)

E=IR is what they taught me in Electrical Engineering school (and
everyone else in the electrical field I believe), so, yeah, it is "out
there". For me I simply cannot say "Voltage equals amps times ohms".
V=AO sounds like a fraterity. Your mileage may vary and we both get
the same values and don't melt wires and stuff.

WARNING - Boring science content below...

E = "electromotive force" (EMF)
I = the German Intensität meaning "intensity".

Go figure. Blame it all on Herr Ohm. At least the R still is the
letter that starts resistance (which came from the German resistanz it
seems).

John "Eee equals Eye Are" DeRosa

A simpler version and memorizable is:

_ P_ _ E_
I ! E I ! R

PIE and EIR is all you have to remember fill in any two values and divide
top from bottom and multiply across. example:
P/I=E, P/E=I, IxE=P E/I=R, E/R=I, IxR=E

P=Watts (power or VA)
I = Amps (current or flow)
E = Volts (EMF electromotive force)
R= Ohms (Resistance)

Graphics are not good in a text editor but consider the underlines are
solid and the exclamation point is solid and conected to the line also put
a circle around each set of three. With that in mind, if you have any two
you can get the other two, this is for DC only by the way. This was also a
Navy school way of remembering the basics. The other one so fondly
remembered was:

"Bad Boys Rape Our Young Girls Behind Victory Garden Walls"

for the resistor collor code. As you can see it was way before "Tail
hook"



At 17:53 20 March 2009, ContestID67 wrote:
Yes, in the upper left hand corner it should be Watts X Ohms (not
additive). Turn your head sideways. ;-)

E=3DIR is what they taught me in Electrical Engineering school (and
everyone else in the electrical field I believe), so, yeah, it is "out
there". For me I simply cannot say "Voltage equals amps times ohms".
V=3DAO sounds like a fraterity. Your mileage may vary and we both get
the same values and don't melt wires and stuff.

WARNING - Boring science content below...

E =3D "electromotive force" (EMF)
I =3D the German Intensit=E4t meaning "intensity".

Go figure. Blame it all on Herr Ohm. At least the R still is the
letter that starts resistance (which came from the German resistanz it
seems).

John "Eee equals Eye Are" DeRosa