Understanding voltage

[krw]

In article <RfsEk.1952$ZP4.394@nlpi067.nbdc.sbc.com>,
Jon_Slaughter@Hotmail.com says...

"krw" <krw@att.bizzzzzzzzzz> wrote in message
news:MPG.234b62ace17ca7e698a24b@news.individual.net...
In article <gkhEk.2759$be.1230@nlpi061.nbdc.sbc.com>,
Jon_Slaughter@Hotmail.com says...
...
Nice job. Now he can go into fourth year.
No wonder our bridges are falling down.

When did one have to understand electricity to understand how to build a
bridge?

Mechanical engineers don't build bridges either. They do build
automobiles and robots, though. Basic electricity would seem to be
a useful thing for MEs. Basic physics is rather useful, and
required, for EEs. MEs don't have to take the EM semester of
physics?


Ok... yes, I know that. Alhtough the overlap is much greater. Learning about
your statics and dynamics is a major part of ME and CE'.

My response was specifically to the statement by Rose.

Understand. I was debating which one to respond to. ;-)

I'd rather the guy know squat about electricity and be a great bridge
builder than build shitty ass bridges cause he spent to much time trying
to
learn about electricity for some school requirements to "broaden his
horizons". He could have spent that time more wisely.

Try a civil engineer if you want a bridge built. I'd rather my
civil engineer had the full load of physics too. We *are* talking
about basic electricity here.
Keith

True... but again, my statement was specifically about roses statement.

He/She is implying that if you don't know even the basics of electricity
then somehow you can't build a good bridge.

I don't think you should be an engineer without some knowledge of
basic physics. The fundamental units are rather important in all
engineering disciplines. I'm surely not an ME, but I know F=MA and
you can't push with a rope. ;-)

What I'm implying is that if the guy is an amazing bridge buildering(Ok, I
know he's ME but Rose is the one who brought up the bridge building) then
it's ok for him to suck as EE.

"Suck as an EE" <> "sucks at fundamental physics"

I'm sure Tesla sucked at ice hockey but I don't see anyone complaining that
he should have spent more time on it. (What does ice hockey have to do with
EE? Who knows but thats not the point)

Understandable. I didn't learn any ice hockey in college physics
either.

Also we are getting off the point as if the guy is suppose to be the best.
There are many EE's that don't even have a good understanding of their own
craft so we should get onto those guys first.

The argument wasn't about whether or not there are EEs who shouldn't
be, rather whether it's understandable for an ME to lack basic
electrical knowledge. Would you think it OK for an EE to not know
that F=MA?

--
Keith

 

[RoyLFuchs]

On Mon, 29 Sep 2008 19:43:54 -0500, John Fields
<jfields@austininstruments.com> wrote:

On Mon, 29 Sep 2008 17:36:14 -0700 (PDT), Rose <couple7802002@yahoo.com
wrote:

On Sep 29, 6:21 pm, John Fields <jfie...@austininstruments.com> wrote:
On Mon, 29 Sep 2008 11:57:18 -0700 (PDT), Rose <couple7802...@yahoo.com
wrote:



On Sep 29, 9:59 am, bgold12 <bgol...@gmail.com> wrote:
Hey, I'm in 3rd year mechanical engineering and I still don't feel
like I have a strong understanding of what voltage is. Maybe someone
can help explain the concept.

I'm pretty sure I understand what charge is (it's just a fundamental
property of subatomic particles that affect the way they interact,
i.e. a charged particle induces a force on a surrounding charged
particle based on their charges (+e for a proton, -e for an electron,
and 0 for a neutron) and the distance and properties of the volume
between them), and I'm pretty sure I understand current, which is just
moving charges (I picture a bunch of electrons moving through a volume
between idle nuclei). But I don't get the concept of voltage. I know
it's produced from a separation of charges, and it is energy per
charge, or Joules/Coulomb, but where is the energy contained? How does
the coulomb of charged particles "have" this energy, and how is it
possible that there can be different amounts of energy associated with
a fixed amount of charged particles (i.e. you can have 10 joules/2
coulombs = 5 volts, but you can also have 20 joules/2 coulombs = 10
volts?)?

I hope that was clear, but it probably wasn't.

Thanks,

bgold12

What I can't understand is how a person can be in third year
engineering and not have a strong understanding of what voltage is.

---
Do you also "can't understand" why he may not have a strong
understanding of what a "parsec" is, or a "millihelen", or a zillion
other terms which aren't relevant to his discipline?

Instead of offering him help, as others have done, why do you ridicule
him for seeking knowledge when you should be commending him for the
courage he mustered in exposing his ignorance and asking for help before
the likes of you?

Perhaps because you have no help to give and are intent on pulling your
betters down in order to make your position on the food chain seem
higher than it actually is?

Some roses by any other name would smell as foul.

JF

At least I wasn't being cranky.

---
Please...

You were being much worse than cranky, you were being intentionally
disingenuous.

JF

The idiot is probably an ObamaTard too.

 

[Archimedes' Lever]

On Mon, 29 Sep 2008 19:01:45 -0700 (PDT), Gerald Newton
<GeraldCNewton@hotmail.com> wrote:

It is the Fourier heat transfer equation.

Minus a good margin to keep things from ever approaching the flash point
of paper... at the very least. It is actually held to a temperature
even lower than that. The flash point (or melting point_ of PVC is
likely lower than that of paper. Why PVC is still in use is beyond me.

 

[RoyLFuchs]

On Mon, 29 Sep 2008 23:02:58 -0700, Salmon Egg <SalmonEgg@sbcglobal.net>
wrote:

I am no longer surprised.

As was stated earlier... your assessments here are worth exactly squat!

 

[Archimedes' Lever]

On Mon, 29 Sep 2008 23:09:16 -0700, Salmon Egg <SalmonEgg@sbcglobal.net>
wrote:

In article <gkhEk.2759$be.1230@nlpi061.nbdc.sbc.com>,
"Jon Slaughter" <Jon_Slaughter@Hotmail.com> wrote:

...
Nice job. Now he can go into fourth year.
No wonder our bridges are falling down.

When did one have to understand electricity to understand how to build a
bridge?


I'd rather the guy know squat about electricity and be a great bridge
builder than build shitty ass bridges cause he spent to much time trying to
learn about electricity for some school requirements to "broaden his
horizons". He could have spent that time more wisely.

One reason to know something about electricity, that many EE's might not
know, is to understand corrosion and cathodic protection. A few years
ago, I saw a railroad bridge that was so rusted out that it would have
scared the hell out of me if I had to ride over it. Similar problems
exist in highway bridges. It really becomes scary when you think of what
improper protection of rebar could do.

Bill

Well... that one at least showed a hint of knowledge.

Ever seen such devices attached to ships?

 

[StickThatInYourPipeAndSmo]

On Tue, 30 Sep 2008 08:44:49 -0700 (PDT), Rose <couple7802002@yahoo.com>
wrote:

On Sep 30, 12:02 am, Salmon Egg <Salmon...@sbcglobal.net> wrote:
According to the California Department of Consumer affairs, the initial
PE exam pass rate is lower for EE's than for any other branch of
engineering. Having found the exam relatively easy, I had a hard time
believing that. Nevertheless after seeing many of the posts on this
subject, I am no longer surprised.

Bill

--
Private Profit; Public Poop! Avoid collateral windfall!

My brother in law is a ME. He thinks banging the
mouse on the desk helps speed up the computer.

I'd bet that is not what he thinks, nor id that why he does it.

Feel lucky that he doesn't go full on bi-polar on you... literally.

 

[Robert Monsen]

On Mon, 29 Sep 2008 08:59:02 -0700 (PDT), bgold12 <bgold12@gmail.com>
wrote:

Hey, I'm in 3rd year mechanical engineering and I still don't feel
like I have a strong understanding of what voltage is. Maybe someone
can help explain the concept.

I'm pretty sure I understand what charge is (it's just a fundamental
property of subatomic particles that affect the way they interact,
i.e. a charged particle induces a force on a surrounding charged
particle based on their charges (+e for a proton, -e for an electron,
and 0 for a neutron) and the distance and properties of the volume
between them), and I'm pretty sure I understand current, which is just
moving charges (I picture a bunch of electrons moving through a volume
between idle nuclei). But I don't get the concept of voltage. I know
it's produced from a separation of charges, and it is energy per
charge, or Joules/Coulomb, but where is the energy contained?

Just like the electric field is force between charges divided by
charge, electric potential (ie, voltage) is potential energy divided
by charge.

You aren't having trouble with voltage, though. You are having issues
with energy. What is it? Think about that for a bit before
continuing...

My answer is that it is the potential to move something. When you hold
a hunk of matter above the ground, it has the potential to start
accelerating when you let go of it. Thus, it has potential energy,
given to it by the attraction of gravity. How much? It depends on how
high you hold it.

Same thing for voltage. It is the potential to move charged particles
around (ie, create a current).

How does
the coulomb of charged particles "have" this energy, and how is it
possible that there can be different amounts of energy associated with
a fixed amount of charged particles (i.e. you can have 10 joules/2
coulombs = 5 volts, but you can also have 20 joules/2 coulombs = 10
volts?)?

Just like the attraction of gravity gives a hunk of matter different
'potential energy' at different altitudes above the ground. So, to get
the hunk of matter up there, somebody had to give it some energy.

To get 10 volts out of 2 coulombs, you need to put in 20 joules of
energy to separate the charges.

I hope that was clear, but it probably wasn't.

Thanks,

bgold12

Voltage, as used in electronics, is a relative measure. You pick some
place in the circuit, and say "that is ground", meaning that is where
you measure the rest of the voltages from. Then, take a particle, like
an electron, and integrate the force it takes you to move it to some
other place in the circuit with respect to distance. Thankfully, it
doesn't matter how you go, any path will do. Now, divide by the charge
of the particle. That number will equal the voltage at the destination
point, relative to the ground of the circuit.

In physics, there are actually two potential fields, the electrostatic
potential, and the vector potential. Those fields, the first a scalar
field, and the second a vector field, influence how a charge will
move. A charge will move along the gradient of the electrostatic
field, and a moving charge will turn to align its motion with the
vector potential.

Regards,
bob monsen

 

[John Fields]

On Tue, 30 Sep 2008 18:28:18 -0500, krw <krw@att.bizzzzzzzzzz> wrote:

In article <RfsEk.1952$ZP4.394@nlpi067.nbdc.sbc.com>,
Jon_Slaughter@Hotmail.com says...

"krw" <krw@att.bizzzzzzzzzz> wrote in message
news:MPG.234b62ace17ca7e698a24b@news.individual.net...
In article <gkhEk.2759$be.1230@nlpi061.nbdc.sbc.com>,
Jon_Slaughter@Hotmail.com says...
...
Nice job. Now he can go into fourth year.
No wonder our bridges are falling down.

When did one have to understand electricity to understand how to build a
bridge?

Mechanical engineers don't build bridges either. They do build
automobiles and robots, though. Basic electricity would seem to be
a useful thing for MEs. Basic physics is rather useful, and
required, for EEs. MEs don't have to take the EM semester of
physics?


Ok... yes, I know that. Alhtough the overlap is much greater. Learning about
your statics and dynamics is a major part of ME and CE'.

My response was specifically to the statement by Rose.

Understand. I was debating which one to respond to. ;-)

I'd rather the guy know squat about electricity and be a great bridge
builder than build shitty ass bridges cause he spent to much time trying
to
learn about electricity for some school requirements to "broaden his
horizons". He could have spent that time more wisely.

Try a civil engineer if you want a bridge built. I'd rather my
civil engineer had the full load of physics too. We *are* talking
about basic electricity here.
Keith

True... but again, my statement was specifically about roses statement.

He/She is implying that if you don't know even the basics of electricity
then somehow you can't build a good bridge.

I don't think you should be an engineer without some knowledge of
basic physics. The fundamental units are rather important in all
engineering disciplines. I'm surely not an ME, but I know F=MA and
you can't push with a rope. ;-)

What I'm implying is that if the guy is an amazing bridge buildering(Ok, I
know he's ME but Rose is the one who brought up the bridge building) then
it's ok for him to suck as EE.

"Suck as an EE" <> "sucks at fundamental physics"

I'm sure Tesla sucked at ice hockey but I don't see anyone complaining that
he should have spent more time on it. (What does ice hockey have to do with
EE? Who knows but thats not the point)

Understandable. I didn't learn any ice hockey in college physics
either.

---
Not even anything about the interface between the blade and the ice and
how the blade was ground?

Pity...
---

Also we are getting off the point as if the guy is suppose to be the best.
There are many EE's that don't even have a good understanding of their own
craft so we should get onto those guys first.

The argument wasn't about whether or not there are EEs who shouldn't
be, rather whether it's understandable for an ME to lack basic
electrical knowledge. Would you think it OK for an EE to not know
that F=MA?

---
Not really, but on the electrical side of elementary physics we're
taught that:

F = MA

is the same as:

E = IR

Where E is a force exerted across a boundary,
I is the flow of mass across that boundary per unit time, and
R is the resistance to that flow.

JF

 

[Rose]

On Sep 30, 6:14 pm, StickThatInYourPipeAndSmokeIt
<Zarathus...@thusspoke.org> wrote:

On Tue, 30 Sep 2008 08:44:49 -0700 (PDT), Rose <couple7802...@yahoo.com
wrote:

On Sep 30, 12:02 am, Salmon Egg <Salmon...@sbcglobal.net> wrote:
According to the California Department of Consumer affairs, the initial
PE exam pass rate is lower for EE's than for any other branch of
engineering. Having found the exam relatively easy, I had a hard time
believing that. Nevertheless after seeing many of the posts on this
subject, I am no longer surprised.

Bill

--
Private Profit; Public Poop! Avoid collateral windfall!

My brother in law is a ME. He thinks banging the
mouse on the desk helps speed up the computer.

 I'd bet that is not what he thinks, nor id that why he does it.

  Feel lucky that he doesn't go full on bi-polar on you... literally.

He has. Many times.

 

[krw]

In article <J7zEk.2061$Ws1.292@nlpi064.nbdc.sbc.com>,
Jon_Slaughter@Hotmail.com says...

"krw" <krw@att.bizzzzzzzzzz> wrote in message
news:MPG.234c71f1de11c55b98a24d@news.individual.net...
In article <RfsEk.1952$ZP4.394@nlpi067.nbdc.sbc.com>,
Jon_Slaughter@Hotmail.com says...

"krw" <krw@att.bizzzzzzzzzz> wrote in message
news:MPG.234b62ace17ca7e698a24b@news.individual.net...
In article <gkhEk.2759$be.1230@nlpi061.nbdc.sbc.com>,
Jon_Slaughter@Hotmail.com says...
...
Nice job. Now he can go into fourth year.
No wonder our bridges are falling down.

When did one have to understand electricity to understand how to build
a
bridge?

Mechanical engineers don't build bridges either. They do build
automobiles and robots, though. Basic electricity would seem to be
a useful thing for MEs. Basic physics is rather useful, and
required, for EEs. MEs don't have to take the EM semester of
physics?


Ok... yes, I know that. Alhtough the overlap is much greater. Learning
about
your statics and dynamics is a major part of ME and CE'.

My response was specifically to the statement by Rose.

Understand. I was debating which one to respond to. ;-)

I'd rather the guy know squat about electricity and be a great bridge
builder than build shitty ass bridges cause he spent to much time
trying
to
learn about electricity for some school requirements to "broaden his
horizons". He could have spent that time more wisely.

Try a civil engineer if you want a bridge built. I'd rather my
civil engineer had the full load of physics too. We *are* talking
about basic electricity here.
Keith

True... but again, my statement was specifically about roses statement.

He/She is implying that if you don't know even the basics of electricity
then somehow you can't build a good bridge.

I don't think you should be an engineer without some knowledge of
basic physics. The fundamental units are rather important in all
engineering disciplines. I'm surely not an ME, but I know F=MA and
you can't push with a rope. ;-)

What I'm implying is that if the guy is an amazing bridge buildering(Ok,
I
know he's ME but Rose is the one who brought up the bridge building) then
it's ok for him to suck as EE.

"Suck as an EE" <> "sucks at fundamental physics"

I'm sure Tesla sucked at ice hockey but I don't see anyone complaining
that
he should have spent more time on it. (What does ice hockey have to do
with
EE? Who knows but thats not the point)

Understandable. I didn't learn any ice hockey in college physics
either.

Also we are getting off the point as if the guy is suppose to be the
best.
There are many EE's that don't even have a good understanding of their
own
craft so we should get onto those guys first.

The argument wasn't about whether or not there are EEs who shouldn't
be, rather whether it's understandable for an ME to lack basic
electrical knowledge. Would you think it OK for an EE to not know
that F=MA?

First off he's still in school... and second he said he didn't understand
voltage... that is only one concept in a huge number of concepts. Also we do
not know to what extent he didn't understand.

Third year. He's specializing by now.

I can promise you that many EE graduates do not understand voltage but only
memorized formulas and defnitions..

Irrelevant.

So it isn't about what's right or wrong but what is real and not real. Sure
I would want everyone to have a little knowledge of everything... but that
isn't practical because then end up not being good at one thing

It certainly is *EXPECTED* that a Junior in an engineering college
knows the rudiments of physics.

Did you ever stop to think that maybe the reason he didn't understand it was
that the professor that he took the class from that taught it didn't do a
good job? Do you also realize that there are many levels of understanding
it?

Possible, but irrelevant.

It's not that I don't agree with you that he should understand it and I'm
not even debating that.

Then what, exactly, are you debating?

But let me ask you something: Suppose he is the best bridge builder in the
world but he doesn't understand voltage... is it "ok"? Can we let it slide
or do we have to send the guy back to kindegarten to learn it? What if it
just can't do it and totally sucks at it? and he doesn't go around
pretending not too but just wants to build bridges... surely it's ok? It's
much better than 99% that don't know and don't give a shit about anything?

He's not the "best bridge builder". He's a college student who
apparently slept through physics. No, I don't want him building my
bridge.

I think you guys are jumping to to many conclusions about the guy. We do not
know his circumstances and shouldn't judge him from one post on usenet that
says

"Hey, I'm in 3rd year mechanical engineering and I still don't feel
like I have a strong understanding of what voltage is. Maybe someone
can help explain the concept."

Yes, by the third year he's supposed to have had at least three
semesters of physics, one of which should have been E&M.

In fact the question's he asks are quite fair and natural and means he has
an inquisitive mind. So instead of judge him we should try to help him
understand. As long as he doesn't pretend to know something and long as he
doesn't put peoples life at risk then it's not a problem. Sure we can hope
he will understand everything the first time and learn everything he can but
this isn't a fairy tale.

Ok, I'm not judging him. His college should be boarded up.

--
Keith

 

[Rose]

On Sep 30, 7:35 pm, John Fields <jfie...@austininstruments.com> wrote:

On Tue, 30 Sep 2008 18:28:18 -0500, krw <k...@att.bizzzzzzzzzz> wrote:
In article <RfsEk.1952$ZP4....@nlpi067.nbdc.sbc.com>,
Jon_Slaugh...@Hotmail.com says...

"krw" <k...@att.bizzzzzzzzzz> wrote in message
news:MPG.234b62ace17ca7e698a24b@news.individual.net...
In article <gkhEk.2759$be.1...@nlpi061.nbdc.sbc.com>,
Jon_Slaugh...@Hotmail.com says...
...
Nice job. Now he can go into fourth year.
No wonder our bridges are falling down.

When did one have to understand electricity to understand how to build a
bridge?

Mechanical engineers don't build bridges either.  They do build
automobiles and robots, though.  Basic electricity would seem to be
a useful thing for MEs.  Basic physics is rather useful, and
required, for EEs.  MEs don't have to take the EM semester of
physics?

Ok... yes, I know that. Alhtough the overlap is much greater. Learning about
your statics and dynamics is a major part of ME and CE'.

My response was specifically to the statement by Rose.

Understand.  I was debating which one to respond to.  ;-)

I'd rather the guy know squat about electricity and be a great bridge
builder than build shitty ass bridges cause he spent to much time trying
to
learn about electricity for some school requirements to "broaden his
horizons".  He could have spent that time more wisely.

Try a civil engineer if you want a bridge built.  I'd rather my
civil engineer had the full load of physics too.  We *are* talking
about basic electricity here.
Keith

True... but again, my statement was specifically about roses statement..

He/She is implying that if you don't know even the basics of electricity
then somehow you can't build a good bridge.

I don't think you should be an engineer without some knowledge of
basic physics.  The fundamental units are rather important in all
engineering disciplines.  I'm surely not an ME, but I know F=MA and
you can't push with a rope.  ;-)

What I'm implying is that if the guy is an amazing bridge buildering(Ok, I
know he's ME but Rose is the one who brought up the bridge building) then
it's ok for him to suck as EE.

"Suck as an EE" <> "sucks at fundamental physics"

I'm sure Tesla sucked at ice hockey but I don't see anyone complaining that
he should have spent more time on it. (What does ice hockey have to do with
EE? Who knows but thats not the point)

Understandable.  I didn't learn any ice hockey in college physics
either.

---
Not even anything about the interface between the blade and the ice and
how the blade was ground?

Pity...
---

Also we are getting off the point as if the guy is suppose to be the best.
There are many EE's that don't even have a good understanding of their own
craft so we should get onto those guys first.

The argument wasn't about whether or not there are EEs who shouldn't
be, rather whether it's understandable for an ME to lack basic
electrical knowledge.  Would you think it OK for an EE to not know
that F=MA?

---
Not really, but on the electrical side of elementary physics we're
taught that:

     F = MA

is the same as:

     E = IR

Where E is a force exerted across a boundary,
      I is the flow of mass across that boundary per unit time, and
      R is the resistance to that flow.

JF

Congrats.. Somebody got it right.
Why didn't someone tell him to
understand Ohm's law?

 

[Jasen Betts]

On 2008-09-29, bgold12 <bgold12@gmail.com> wrote:

Hey, I'm in 3rd year mechanical engineering and I still don't feel
like I have a strong understanding of what voltage is. Maybe someone
can help explain the concept.

I'm pretty sure I understand what charge is (it's just a fundamental
property of subatomic particles that affect the way they interact,
i.e. a charged particle induces a force on a surrounding charged
particle based on their charges (+e for a proton, -e for an electron,
and 0 for a neutron) and the distance and properties of the volume
between them), and I'm pretty sure I understand current, which is just
moving charges (I picture a bunch of electrons moving through a volume
between idle nuclei). But I don't get the concept of voltage.

if you picture current as the rate of flow of water in a pipe, voltage
is the water pressure.

I know
it's produced from a separation of charges, and it is energy per
charge, or Joules/Coulomb, but where is the energy contained?

in the water analogy: Joules / Cubic meter IOW: pascals

How does the coulomb of charged particles "have" this energy,

it has it by being displaced by a from where it would like to rest
the further it is displaced the higher the voltage.

and how is it possible that there can be different amounts of energy
associated with a fixed amount of charged particles (i.e. you can have 10 joules/2
coulombs = 5 volts, but you can also have 20 joules/2 coulombs = 10
volts?)?

different pressures, with 10kPa you can spin a turbine nicely,
but same flow rate with only 10Pa behind can do very little work.

Bye.
Jasen

 

[Jasen Betts]

On 2008-09-30, Rose <couple7802002@yahoo.com> wrote:

My brother in law is a ME. He thinks banging the
mouse on the desk helps speed up the computer.

Unfortunately sometimes it does.

Early versions of one popular M68K based machine (I forget which)
had a bug that was helped by moving the mouse which generated extra
interruots and sped things up.

Bye.
Jasen

 

[Jasen Betts]

On 2008-09-30, Jon Slaughter <Jon_Slaughter@Hotmail.com> wrote:

I'd rather the guy know squat about electricity and be a great bridge
builder than build shitty ass bridges cause he spent to much time trying to
learn about electricity for some school requirements to "broaden his
horizons". He could have spent that time more wisely.

Bridges are civil engineering aren't they?



--

Bye.
Jasen

 

[krw]

In article <9kCEk.2219$c45.1628@nlpi065.nbdc.sbc.com>,
Jon_Slaughter@Hotmail.com says...

"krw" <krw@att.bizzzzzzzzzz> wrote in message
news:MPG.234caadfbe80755a98a255@news.individual.net...
In article <J7zEk.2061$Ws1.292@nlpi064.nbdc.sbc.com>,
Jon_Slaughter@Hotmail.com says...

"krw" <krw@att.bizzzzzzzzzz> wrote in message
news:MPG.234c71f1de11c55b98a24d@news.individual.net...
In article <RfsEk.1952$ZP4.394@nlpi067.nbdc.sbc.com>,
Jon_Slaughter@Hotmail.com says...

"krw" <krw@att.bizzzzzzzzzz> wrote in message
news:MPG.234b62ace17ca7e698a24b@news.individual.net...
In article <gkhEk.2759$be.1230@nlpi061.nbdc.sbc.com>,
Jon_Slaughter@Hotmail.com says...
...
Nice job. Now he can go into fourth year.
No wonder our bridges are falling down.

When did one have to understand electricity to understand how to
build
a
bridge?

Mechanical engineers don't build bridges either. They do build
automobiles and robots, though. Basic electricity would seem to be
a useful thing for MEs. Basic physics is rather useful, and
required, for EEs. MEs don't have to take the EM semester of
physics?


Ok... yes, I know that. Alhtough the overlap is much greater. Learning
about
your statics and dynamics is a major part of ME and CE'.

My response was specifically to the statement by Rose.

Understand. I was debating which one to respond to. ;-)

I'd rather the guy know squat about electricity and be a great
bridge
builder than build shitty ass bridges cause he spent to much time
trying
to
learn about electricity for some school requirements to "broaden
his
horizons". He could have spent that time more wisely.

Try a civil engineer if you want a bridge built. I'd rather my
civil engineer had the full load of physics too. We *are* talking
about basic electricity here.
Keith

True... but again, my statement was specifically about roses
statement.

He/She is implying that if you don't know even the basics of
electricity
then somehow you can't build a good bridge.

I don't think you should be an engineer without some knowledge of
basic physics. The fundamental units are rather important in all
engineering disciplines. I'm surely not an ME, but I know F=MA and
you can't push with a rope. ;-)

What I'm implying is that if the guy is an amazing bridge
buildering(Ok,
I
know he's ME but Rose is the one who brought up the bridge building)
then
it's ok for him to suck as EE.

"Suck as an EE" <> "sucks at fundamental physics"

I'm sure Tesla sucked at ice hockey but I don't see anyone complaining
that
he should have spent more time on it. (What does ice hockey have to do
with
EE? Who knows but thats not the point)

Understandable. I didn't learn any ice hockey in college physics
either.

Also we are getting off the point as if the guy is suppose to be the
best.
There are many EE's that don't even have a good understanding of their
own
craft so we should get onto those guys first.

The argument wasn't about whether or not there are EEs who shouldn't
be, rather whether it's understandable for an ME to lack basic
electrical knowledge. Would you think it OK for an EE to not know
that F=MA?

First off he's still in school... and second he said he didn't understand
voltage... that is only one concept in a huge number of concepts. Also we
do
not know to what extent he didn't understand.

Third year. He's specializing by now.

I can promise you that many EE graduates do not understand voltage but
only
memorized formulas and defnitions..

Irrelevant.

So it isn't about what's right or wrong but what is real and not real.
Sure
I would want everyone to have a little knowledge of everything... but
that
isn't practical because then end up not being good at one thing

It certainly is *EXPECTED* that a Junior in an engineering college
knows the rudiments of physics.

Did you ever stop to think that maybe the reason he didn't understand it
was
that the professor that he took the class from that taught it didn't do a
good job? Do you also realize that there are many levels of
understanding
it?

Possible, but irrelevant.

It's not that I don't agree with you that he should understand it and I'm
not even debating that.

Then what, exactly, are you debating?

But let me ask you something: Suppose he is the best bridge builder in
the
world but he doesn't understand voltage... is it "ok"? Can we let it
slide
or do we have to send the guy back to kindegarten to learn it? What if it
just can't do it and totally sucks at it? and he doesn't go around
pretending not too but just wants to build bridges... surely it's ok?
It's
much better than 99% that don't know and don't give a shit about
anything?

He's not the "best bridge builder". He's a college student who
apparently slept through physics. No, I don't want him building my
bridge.

I think you guys are jumping to to many conclusions about the guy. We do
not
know his circumstances and shouldn't judge him from one post on usenet
that
says

"Hey, I'm in 3rd year mechanical engineering and I still don't feel
like I have a strong understanding of what voltage is. Maybe someone
can help explain the concept."

Yes, by the third year he's supposed to have had at least three
semesters of physics, one of which should have been E&M.

In fact the question's he asks are quite fair and natural and means he
has
an inquisitive mind. So instead of judge him we should try to help him
understand. As long as he doesn't pretend to know something and long as
he
doesn't put peoples life at risk then it's not a problem. Sure we can
hope
he will understand everything the first time and learn everything he can
but
this isn't a fairy tale.

Ok, I'm not judging him. His college should be boarded up.


You are making a lot of assumptions here from one small post about one
thing... You should be ashamed of yourself.

Why? He's a third year engineering student that has zero clue about
a rather important aspect of physics that he *SHOULD* have covered.
It is the equivalent of my not knowing what mechanical force was
when I was a college junior. Somebody failed miserably here.

--
Keith

 

[Salmon Egg]

In article <gbvjr0$ueg$3@gonzo>, Jasen Betts <jasen@xnet.co.nz> wrote:

Bridges are civil engineering aren't they?

Some are rocks--like the Wheatstone Bridge.

Bill

--
Private Profit; Public Poop! Avoid collateral windfall!

 

[terryS]

On Sep 29, 1:59 pm, bgold12 <bgol...@gmail.com> wrote:

Hey, I'm in 3rd year mechanical engineering and I still don't feel
like I have a strong understanding of what voltage is. Maybe someone
can help explain the concept.

I'm pretty sure I understand what charge is (it's just a fundamental
property of subatomic particles that affect the way they interact,
i.e. a charged particle induces a force on a surrounding charged
particle based on their charges (+e for a proton, -e for an electron,
and 0 for a neutron) and the distance and properties of the volume
between them), and I'm pretty sure I understand current, which is just
moving charges (I picture a bunch of electrons moving through a volume
between idle nuclei). But I don't get the concept of voltage. I know
it's produced from a separation of charges, and it is energy per
charge, or Joules/Coulomb, but where is the energy contained? How does
the coulomb of charged particles "have" this energy, and how is it
possible that there can be different amounts of energy associated with
a fixed amount of charged particles (i.e. you can have 10 joules/2
coulombs = 5 volts, but you can also have 20 joules/2 coulombs = 10
volts?)?

I hope that was clear, but it probably wasn't.

Thanks,

bgold12

That's making it too bloody complicated.
Absolutely basic that:
Voltage (Or EMF, electro motive force, or potential or whatever you
want to call it) is the pressure that can push an electric current
through a circuit.
The source of the voltage can be various devices, such as a battery, a
generator or a storage device such as capacitor.
'Voltages' can be DC (Direct current) or AC (Alternating current).
Take a pencil and draw a square to represent 'the source'.
Then draw a circuit from and external to the source comprising wires
(which have virtually no resistance in most practical applications)
and a load (which could be say a single heating resistor of R ohms).
Electric current (amps) will flow in the above circuit. The higher the
voltage the greater the current that will traverse the circuit.
The formula; Ohm's Law is Voltage/Circuit Resistance = Current flow.
A practical example being 230 volts, a 20 ohm resistor, and a
resulting current flow of 230/20 = 11.5 amps
If you want to get into the amount of power (watts, or watts per hour)
how many coulombs of energy are being transferred you can make further
calculations.
But the above is basic.
PS. Working in telecommunications for some 40 years we once had a boss
who was an 'Industrial Engineer'. We (experienced subordinates) always
gave him a hard time saying "Well who can expect an Industrial
Engineer to understand electricity with more than one frequency!"
So congratulations to the OP on wanting to understand electricity.

 

[whit3rd]

On Sep 29, 8:59 am, bgold12 <bgol...@gmail.com> wrote:

Hey, I'm in 3rd year mechanical engineering and I still don't feel
like I have a strong understanding of what voltage is....

I'm pretty sure I understand what charge is (it's just a fundamental
property of subatomic particles

There's a fascinating bit of philosophy hidden in this inquiry.
Voltage and charge are two completely different kinds of
physical quantities, and the distinction between these
is repeated in many different ways over all disciplines (which
is why so many analogies are offered when the question comes up).

Voltage is an example of an intensive quantity. Charge is an
example of an extensive quantity. If you consider a system (like,
let's take a battery/bulb flashlight), the voltage of that battery is
an intensive quantity, and the charge that the battery can deliver is
an extensive quantity. Double the flashlight, and there are two
batteries and two bulbs,twice the charge, but the voltage is the same.
Double the dimensions of the flashlight, the bigger battery has
eight times the charge, but the voltage is STILL the same.

Extensive quantities include mass, charge, cost of a bag of potatoes.
Intensive quantities include density, voltage, cost per pound of
potatoes.

Voltage, in particular, is the ratio of two extensive quantities,
stored
electrical energy and stored electric charge, in the sense of taking
a derivative of energy with respect to charge. Just like the
cost per pound of potatoes, it's intensive.

The implications of this include another check you can perform on
equations: you can't add or equate intensive and extensive quantities,
just like quantities with different units.

 

[stan]

krw wrote:

In article <J7zEk.2061$Ws1.292@nlpi064.nbdc.sbc.com>,
Jon_Slaughter@Hotmail.com says...

"krw" <krw@att.bizzzzzzzzzz> wrote in message
news:MPG.234c71f1de11c55b98a24d@news.individual.net...
In article <RfsEk.1952$ZP4.394@nlpi067.nbdc.sbc.com>,
Jon_Slaughter@Hotmail.com says...

"krw" <krw@att.bizzzzzzzzzz> wrote in message
news:MPG.234b62ace17ca7e698a24b@news.individual.net...
In article <gkhEk.2759$be.1230@nlpi061.nbdc.sbc.com>,
Jon_Slaughter@Hotmail.com says...
snip

But let me ask you something: Suppose he is the best bridge builder in the
world but he doesn't understand voltage... is it "ok"? Can we let it slide
or do we have to send the guy back to kindegarten to learn it? What if it
just can't do it and totally sucks at it? and he doesn't go around
pretending not too but just wants to build bridges... surely it's ok? It's
much better than 99% that don't know and don't give a shit about anything?

He's not the "best bridge builder". He's a college student who
apparently slept through physics. No, I don't want him building my
bridge.

Quite a leap to that conclusion. If the young man was anywhere near as
unmotivated as the picture you paint, there's simply no way he would be
asking.

I think you guys are jumping to to many conclusions about the guy. We do not
know his circumstances and shouldn't judge him from one post on usenet that
says

"Hey, I'm in 3rd year mechanical engineering and I still don't feel
like I have a strong understanding of what voltage is. Maybe someone
can help explain the concept."

Yes, by the third year he's supposed to have had at least three
semesters of physics, one of which should have been E&M.

I guess you slept through curriculum design. At best part of one
semester provided familiarity with the subject, but certainly nothing in
depth.

In fact the question's he asks are quite fair and natural and means he has
an inquisitive mind. So instead of judge him we should try to help him
understand. As long as he doesn't pretend to know something and long as he
doesn't put peoples life at risk then it's not a problem. Sure we can hope
he will understand everything the first time and learn everything he can but
this isn't a fairy tale.

Ok, I'm not judging him. His college should be boarded up.

There wouldn't be many left open. He never said he new NOTHING about
voltage, he said he didn't feel comfortable with his understanding. So
far, the kid is trying; you seem to be going out of the way to be
unhelpful and critical. What college did you attend?
>

 

[Don Kelly]

----------------------------
"RoyLFuchs" <RoyLFuchs@urfargingicehole.org> wrote in message
news:jof5e4l3lqvq0m6afcopkrf1nafdsupl4l@4ax.com...

On Mon, 29 Sep 2008 23:02:58 -0700, Salmon Egg <SalmonEgg@sbcglobal.net
wrote:

I am no longer surprised.


As was stated earlier... your assessments here are worth exactly squat!

---
Actually, Salmon Egg knows more about electricity than most contributing to
this group. Do you have a problem with that?

--

Don Kelly dhky@shawcross.ca
remove the X to answer