Need help understanding voltage

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In summary: The key point is that voltage is relative between two points. When you measure voltage, you are measuring the difference in energy concentration between those two points. So if you have a resistor, there will be a difference in energy concentration (voltage) between the two ends of it, but the total amount of energy per charge does not decrease. It's like a water slide - the water at the top has more potential energy (higher voltage) than the water at the bottom, but the total amount of water (charge) is the same. The resistor just decreases the voltage difference, not the total amount of energy per charge. Does that make more sense?In summary, voltage is a measure of the energy concentration per unit
  • #1
remedemic
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Greetings,

I am a high school student that is trying to learn about electronics and circuits for a hobby, and I just cannot understand voltage. Some resources are telling me that it is a "potential difference" between two points, while other resources are telling me that it is simply the electrical force being exerted at a certain point. With the first definition, I am under the impression that two points are needed to measure voltage, while with the second definition, voltage can be measured at one single point.

Could someone explain to me what voltage exactly is in the most basic form possible?
Help would be greatly appreciated! Thank you.
 
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  • #2
  • #3
remedemic,

... and I just cannot understand voltage. Some resources are telling me that it is a "potential difference" between two points, while other resources are telling me that it is simply the electrical force being exerted at a certain point. With the first definition, I am under the impression that two points are needed to measure voltage, while with the second definition, voltage can be measured at one single point.

Could someone explain to me what voltage exactly is in the most basic form possible?

Sure, voltage is the electrical energy density of an amount of charge. It is measured in joules per coulomb. Suppose you have a bunch of electons. They all have like charges, so they don't like to get together. In fact, they repel each other. It takes energy to force them into a finite space. The amount of energy (joules) it takes divided by the charge (coulombs) is the voltage. If you put additional electrons into the same space, it takes more energy, and the voltage will be higher. If you crowd the same number of electrons into a smaller space, more energy will be needed, and the voltage will again be higher. So voltage is a measure of the energy concentration per unit of charge (joules/coulomb). If one point is at a higher energy concentration (higher voltage) than another point, the electrons are going to move and spread out from the higher energy concentration (higher voltage) to the lower concentration (lower voltage), provided there is a conduction path.

Wrap your mind around the above and then ask more questions.

Ratch
 
  • #4
remedemic said:
Greetings,

I am a high school student that is trying to learn about electronics and circuits for a hobby, and I just cannot understand voltage. Some resources are telling me that it is a "potential difference" between two points, while other resources are telling me that it is simply the electrical force being exerted at a certain point. With the first definition, I am under the impression that two points are needed to measure voltage, while with the second definition, voltage can be measured at one single point.

Could someone explain to me what voltage exactly is in the most basic form possible?
Help would be greatly appreciated! Thank you.

Voltage is, as you said, potential difference and involves two points. That's why voltmeters have two leads.

Try this experiment - take an ordinary nine volt battery and place one terminal to the tip of your tongue. No perceptible sensation...
Then place both terminals on your tongue - it darn well stings!

Voltage is "electro-motive force", abbreviated EMF and that's why it is so often designated by "E". The British used to call it "pressure". It 'pushes' electrical energy along . Motive as in moving, Electro as in electric...

Observe that pressure too is a differential measurement. We just had a thread that touched on that - check " Physically Grounded " in the EE section... user dlgoff posted a really neat graphic on page 2.

old jim
 
  • #5
Ratch said:
remedemic,
Sure, voltage is the electrical energy density of an amount of charge. It is measured in joules per coulomb. Suppose you have a bunch of electons. They all have like charges, so they don't like to get together. In fact, they repel each other. It takes energy to force them into a finite space. The amount of energy (joules) it takes divided by the charge (coulombs) is the voltage. If you put additional electrons into the same space, it takes more energy, and the voltage will be higher. If you crowd the same number of electrons into a smaller space, more energy will be needed, and the voltage will again be higher. So voltage is a measure of the energy concentration per unit of charge (joules/coulomb). If one point is at a higher energy concentration (higher voltage) than another point, the electrons are going to move and spread out from the higher energy concentration (higher voltage) to the lower concentration (lower voltage), provided there is a conduction path.

Wrap your mind around the above and then ask more questions.

Ratch

Whilst you are perfectly right to talk about Joules per Coulomb, the terms "energy density" or "concentration" is pretty meaningless because PD had no relationship to volume or area.
Why not stick to a description that involves just the basic quantities involved? If you mean Energy then just say Energy and that's right. There may or may not be a spreading of energy or a concentrating of energy (as with EM fields) but that's not Volts or PD.
 
  • #6
Thanks for the help gentlemen, I can understand voltage alone now, however, I'm having a bit of trouble relating it to resistance at this point.

From what I am reading, a resistor decreases the amount of energy per charge (by converting it into heat or motion through friction), which seems that by definition, voltage would decrease after a resistor, but according to V=IR, and I being constant, voltage goes up?

Could someone clear this confusion up? Thanks again.
 
  • #7
I had to read it twice but I like your explanation Ratch. Electron density basically is what differentiates one voltage from another.
 
  • #8
sophiecentaur,

Whilst you are perfectly right to talk about Joules per Coulomb, the terms "energy density" or "concentration" is pretty meaningless because PD had no relationship to volume or area.

I never mentioned PD in my definition of voltage. However, charge carriers like electrons are a physical mass whose number is defined over a definite volume of space. The energy they contain is what it took to gather them into that definite volume of space. So if there is energy and charge together in a volume, that defines voltage. In other words, voltage is the concentration of energy per unit of charge.

Why not stick to a description that involves just the basic quantities involved?

Energy and charge are the basic quantities, and I gave a description of how they are involved.

If you mean Energy then just say Energy and that's right. There may or may not be a spreading of energy or a concentrating of energy (as with EM fields) but that's not Volts or PD.

I do say "energy" when I mean energy. The energy density per unit charge or energy concentration per unit charge is not a spatial density or spatial concentration. It is simply the amount of energy associated with a gathering of charge carriers no matter how close or far they are apart.

Ratch
 
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  • #9
mearvk,

I had to read it twice but I like your explanation Ratch.

Why thank you. I got it from the units in which voltage is defined.

Electron density basically is what differentiates one voltage from another.

A higher spatial electron density will surely define a higher voltage. But according to Coulomb's law, it won't be a linear one. I think it better to say that voltage is the energy density per unit charge.

Ratch
 
  • #10
remedemic,

...however, I'm having a bit of trouble relating it to resistance at this point.

You should have trouble. Voltage exists by itself without any link to resistance.

which seems that by definition, voltage would decrease after a resistor, but according to V=IR, and I being constant, voltage goes up?

Could someone clear this confusion up? Thanks again.

The correct application of the resistance formula you quoted is V=-IR. The sign is opposite to the voltage source, which I assume for this discussion is positive.

Ratch
 
  • #11
I think this says it all.

http://hyperphysics.phy-astr.gsu.edu/%E2%80%8Chbase/electric/imgele/volcon.gif [Broken]

Play with these Voltage Concepts here.

http://hyperphysics.phy-astr.gsu.edu/%E2%80%8Chbase/electric/volcon.html#c1
 
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  • #12
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  • #13
I really like that graphical representation. Thanks for providing it.
 
  • #14
Ratch said:
sophiecentaur,
I never mentioned PD in my definition of voltage. However, charge carriers like electrons are a physical mass whose number is defined over a definite volume of space. The energy they contain is what it took to gather them into that definite volume of space. So if there is energy and charge together in a volume, that defines voltage. In other words, voltage is the concentration of energy per unit of charge.
Energy and charge are the basic quantities, and I gave a description of how they are involved.
I do say "energy" when I mean energy. The energy density per unit charge or energy concentration per unit charge is not a spatial density or spatial concentration. It is simply the amount of energy associated with a gathering of charge carriers no matter how close or far they are apart.

Ratch

This is clearly a personal view of how you 'deal with' an abstract physical concept and you are , of course, entitled to your internal views of things. However, you have written about this from a presumed 'expert' standpoint. (That is how a beginner could view it and it could lead to serious misunderstanding - which would need to be undone before they could move on usefully)

If you think you can explain Voltage without using the term Potential Difference then you will be disappointed. Voltage is just an informal word for Potential Difference in almost the same way that people use the word 'Amperage' when they mean Current.

Voltage has nothing to do with how many charges there happen to be - unless you are specifically referring to a 'charged' object or a distribution of charge - but that is different (in different Units) from your "Energy Density" idea. You can produce a very high voltage by electromagnetic induction with very small currents (moving charges) or produce massive numbers of moving charges with a very small voltage.

I would be interested to know if you could quote me a textbook that uses your strange form of definition. If you have read something of the sort in a manufacturer's literature then that is of no value. Likewise, for anything buried inside some non-academic 'folksy' post. This is a well enough established concept for it to be dealt with in a textbook. They all agree, of course.

What is wrong with the basic definition of Energy per unit Charge? It is simple and to the point and is not open to any misinterpretation. You seem to think that the term 'concentration' helps in some way. It can hardly do so because you now say that the word concentration does not refer to anything spatial. That's even more confusing / meaningless. And then you introduce Mass into the argument, too.
 
  • #15
sophiecentaur,

This is clearly a personal view of how you 'deal with' an abstract physical concept and you are , of course, entitled to your internal views of things. However, you have written about this from a presumed 'expert' standpoint. (That is how a beginner could view it and it could lead to serious misunderstanding - which would need to be undone before they could move on usefully)

I don't think voltage is an abstract physical concept. I explained my definition of voltage which anyone can evaluate and it does not contradict other definitions of voltage. What would the beginner need to "undo" to advance further?

If you think you can explain Voltage without using the term Potential Difference then you will be disappointed. Voltage is just an informal word for Potential Difference in almost the same way that people use the word 'Amperage' when they mean Current.

I can and did explain it without using potential difference. I did not contradict what is meant by potential difference.

Voltage has nothing to do with how many charges there happen to be - unless you are specifically referring to a 'charged' object or a distribution of charge - but that is different (in different Units) from your "Energy Density" idea. You can produce a very high voltage by electromagnetic induction with very small currents (moving charges) or produce massive numbers of moving charges with a very small voltage.

Voltage is not defined by only charges. Energy is taken into consideration also. Applying a varying voltage to produce a high or low current does not abrogate my definition of voltage.

I would be interested to know if you could quote me a textbook that uses your strange form of definition. If you have read something of the sort in a manufacturer's literature then that is of no value. Likewise, for anything buried inside some non-academic 'folksy' post. This is a well enough established concept for it to be dealt with in a textbook. They all agree, of course.

Nothing strange about it. It comes from the units of voltage (joules/coulomb). They all say voltage units are joules/coulomb.

What is wrong with the basic definition of Energy per unit Charge? It is simple and to the point and is not open to any misinterpretation.

Nothing. It is what I am expounding.

You seem to think that the term 'concentration' helps in some way.

If I put 1 kg of salt into a 1000 kg of water, that mixture will have a particular salt density and a salt concentration.

It can hardly do so because you now say that the word concentration does not refer to anything spatial. That's even more confusing / meaningless.

Did I mention anything spatial in the above analogy? What are you confused about?

And then you introduce Mass into the argument, too.

I only mentioned mass in passing. I said that electrons do have mass. I did not use mass in defining voltage.

Ratch
 
  • #16
Thing I sometimes have trouble understanding is why it's potential difference and not just difference. Surely voltage implies that there are actual differences in charge density not just potential ones?
 
  • #17
mearvc,

Thing I sometimes have trouble understanding is why it's potential difference and not just difference. Surely voltage implies that there are actual differences in charge density not just potential ones?

I corrected you before about that phrase in post #9 of this thread. It is "energy density", not "charge density". The units are joules/coulomb. The amount of charge can be large or small, but the energy density or energy concentration specifies the voltage.

Here is what potential difference means. Its full name is electrical potential energy difference per unit charge or potential difference (PD) for short. Every gathering of charge causes two fields to form. One field is a vector field called the electric field. It is measured by the vector of force on a small test charge caused by the attraction or repulsion of the charge to be studied. Its vector field unit is Newtons/coulomb or the equivalent unit of volts/meter. The other field is a scalar field called the energy or work field. It is the energy it takes to bring a test charge from infinity to within an arbitrary point from the charge (call it P1). Each point around the charge to be studied has a particular scalar energy value determined by the previous description. To find the potential difference, subtract the energy from one point (call it P1) from another point (say P2) and divide by the test charge amount. That gives you the PD or voltage in joules/coulomb or voltage between the two points. Voltage is measured with two points.

Ratch
 
  • #18
Ratch said:
sophiecentaur,
I never mentioned PD in my definition of voltage. However, charge carriers like electrons are a physical mass whose number is defined over a definite volume of space. The energy they contain is what it took to gather them into that definite volume of space. So if there is energy and charge together in a volume, that defines voltage. In other words, voltage is the concentration of energy per unit of charge.
Energy and charge are the basic quantities, and I gave a description of how they are involved.
I do say "energy" when I mean energy. The energy density per unit charge or energy concentration per unit charge is not a spatial density or spatial concentration. It is simply the amount of energy associated with a gathering of charge carriers no matter how close or far they are apart.

Ratch
I may be an old fashioned thing but, when I read the word 'density' in a definition, I expect the units to involve s-2 or s-3 in some form. Once you introduce 'density' into an idea you change things radically. Magnetic Flux and Magnetic Flux Density are not interchangeable terms, for instance.

The confusion that you have managed to introduce into this thread is well demonstrated in the post from mearvk, which you replied to with:
A higher spatial electron density will surely define a higher voltage. But according to Coulomb's law, it won't be a linear one. I think it better to say that voltage is the energy density per unit charge.
which is gobbledegook. Higher electron 'density' does not 'define' a higher voltage. In the case of a charged object, it is true that increasing the charge will increase the voltags (as in Q=CV) but that is a result and not a definition. W=QV does not include a 'density' term.

The trouble is that you don't even seem to realize the confusion you generate by this sort of 'explanation'. Explanations are supposed to help people along the best path towards understanding and not to divert them. There are enough problems when you take the conventional path and we can all do without added confusion. If you cannot show an example of where the word 'density' is used in acknowledged sources for this topic then you should avoid using it in such an authoritative way. It surely cannot help anyone.
 
  • #19
[Middle English potencial, from Old French potenciel, from Late Latin potentilis, powerful, from Latin potentia, power, from potns, potent-, present participle of posse, to be able; see potent.]
 
  • #20
sophiecentaur,

I may be an old fashioned thing but, when I read the word 'density' in a definition, I expect the units to involve s-2 or s-3 in some form. Once you introduce 'density' into an idea you change things radically. Magnetic Flux and Magnetic Flux Density are not interchangeable terms, for instance.

There is also line charge density whose units involves s-1. All the above are spatial densities.

The confusion that you have managed to introduce into this thread is well demonstrated in the post from mearvk, which you replied to with:

A higher spatial electron density will surely define a higher voltage. But according to Coulomb's law, it won't be a linear one. I think it better to say that voltage is the energy density per unit charge.

which is gobbledegook. Higher electron 'density' does not 'define' a higher voltage. In the case of a charged object, it is true that increasing the charge will increase the voltags (as in Q=CV) but that is a result and not a definition. W=QV does not include a 'density' term.

Yes, a higher charge carrier or electron density will define a higher voltage, because more energy will be required to increase the electron density. Both formulas you present have voltage in their terms. Since voltage is an energy density, those formulas do include density.

The trouble is that you don't even seem to realize the confusion you generate by this sort of 'explanation'. Explanations are supposed to help people along the best path towards understanding and not to divert them. There are enough problems when you take the conventional path and we can all do without added confusion. If you cannot show an example of where the word 'density' is used in acknowledged sources for this topic then you should avoid using it in such an authoritative way. It surely cannot help anyone.

I am just thinking out of the box. As I said before, all the "authoritative" sources say that voltage is energy per charge. What is confusing about that? That concept is surely not a mind-bending diversonary thought that will spin someone's mental state out of control.

Ratch
 
  • #21
"Thinking out of the box" is a luxury. Someone who asks a serious question to help their understanding needs everything to be inside the box. Any statement that is obviously outside the box should, at least, be accompanied by some serious caveats and 'imho's.
Your posts on this have been streams of consciousness and not Engineering based.
Why do you end your last post with the correct and well established definition of Voltage as if you never wrote all the other non sequiturs - which was what I have been complaining about?
If you cannot quote any reputable source where this energy density nonsense is used as part of the actual definition of Voltage then you really should climb down and relegate your comments to 'chatting around the subject'.
Have some sympathy for the first timer in this field. He wants a 'definition' and not an arm waving word association game.
 
  • #22
sophiecentaur,

"Thinking out of the box" is a luxury.

No, it is one way new innovations are devised and applied.

Someone who asks a serious question to help their understanding needs everything to be inside the box.

Why is that? I remind you that in post #1, the OP "just cannot understand voltage". All those inside the box explanations he read did not help him.

Any statement that is obviously outside the box should, at least, be accompanied by some serious caveats and 'imho's.

Nope, they should only be explained, defended and shown to be correct.

Your posts on this have been streams of consciousness and not Engineering based.

All thought is a stream of conciousness. I disagree that my post are not engineering based. You, for one, have not proven that to be so.

Why do you end your last post with the correct and well established definition of Voltage as if you never wrote all the other non sequiturs - which was what I have been complaining about?

A non sequitur is a conclusion which does not follow its premise. I believe my conclusion does indeed mesh with the way voltage is employed.

If you cannot quote any reputable source where this energy density nonsense is used as part of the actual definition of Voltage then you really should climb down and relegate your comments to 'chatting around the subject'.

Before you can make the above statement, you have to prove that energy density is nonsense, So far, you have not done so.

Have some sympathy for the first timer in this field. He wants a 'definition' and not an arm waving word association game.

Read the first post again. The OP had resources coming out of his ears. He wanted understanding, not just another definition. I provided him with an explanation to help him understand.

To the OP:
Were you helped by my definition and explanation of voltage in post #3 ?

Ratch
 
  • #23
I don't mean to butt in, too many cooks and all that, but I'm curious about something.

Ratch, how would you explain the voltage produced by electromagnetic induction, using your definition?

Edit: This was worded poorly. Maybe something more along the line of:
In the context of electromagnetic induction, how would you explain what voltage is?
 
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  • #24
Ratch said:
sophiecentaur,
No, it is one way new innovations are devised and applied.
Do you know anything about the process of education (which is what this is about). Throwing random ideas at someone who is having difficulty is certainly not the best way of helping them. How are they supposed to know which is good stuff and which is dodgy?
All thought is a stream of conciousness. I disagree that my post are not engineering based. You, for one, have not proven that to be so.
You are using the wrong definition of a quantity that is well defined. The definition of the Volt does not include any reference to area or volume. That is your error. Why persist in it?
Before you can make the above statement, you have to prove that energy density is nonsense, So far, you have not done so.
As the one who is proposing an alternative definition, it is up to you to justify it - as with all 'alternatives' to mainstream knowledge. I can only say that I have never read anything so whacky. All you need to do is give a simple link / reference to some supporting evidence.

There is just one definition of voltage and it involves Energy and Charge. I notice, you haven't ever suggested a way of actually working out Voltage with your alternative definition. I think it would be reasonable to expect a bit of Maths to support your new definition.
To the OP:
Were you helped by my definition and explanation of voltage in post #3 ?
What sort of touchstone is that? How would he know whether or not he actually got the correct idea from what you have written - except by being given some supporting evidence? You could give someone a very convincing story about the Moon being made of green cheese and they might accept it. That would not make it true.
 
  • #25
This has gotten a bit heated. Maybe we can let it go since it's not even the OP that's persisting in the discussion.
 
  • #26
mearvk said:
This has gotten a bit heated. Maybe we can let it go since it's not even the OP that's persisting in the discussion.
Good idea. :smile:
 
  • #27
milesyoung,

Ratch, how would you explain the voltage produced by electromagnetic induction, using your definition?

Good question. I like it when someone asks questions instead of just rejecting something.

A voltage can be induced in a conductor if the relative motion of a conductor is at right angles to a magnetic flux. This induces a voltage across the ends of the conductor by moving the charges present in the conductor from one end to the other. It takes energy to do this, which comes from the movement through the magnetic field. The energy it takes divided by the charge moved in the conductor is the voltage.

Edit: This was worded poorly. Maybe something more along the line of:
In the context of electromagnetic induction, how would you explain what voltage is?

Same answer as I gave to your first question.

Ratch
 
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  • #28
Ratch,

Lets say there's no conductor present, only a time-varying magnetic field.
 
  • #29
Ratch said:
milesyoung,



Good question. I like it when someone asks questions instead of just rejecting something.

My quote from earlier on:
Voltage has nothing to do with how many charges there happen to be - unless you are specifically referring to a 'charged' object or a distribution of charge - but that is different (in different Units) from your "Energy Density" idea. You can produce a very high voltage by electromagnetic induction with very small currents (moving charges) or produce massive numbers of moving charges with a very small voltage.
I think you were in self defence mode at the time and ignored this.

You seem to be confusing cause and effect here: The induced emf is what causes the charges to move and not due to the charges. Charges don't move without an emf to make them move. The induced Voltage is there whatever resistance the conductor has - the field is there (Volts per metre), even in empty space.
 
  • #30
sophiecentaur,

Do you know anything about the process of education (which is what this is about). Throwing random ideas at someone who is having difficulty is certainly not the best way of helping them.

Not much. I don't think too many participants in this forum are professional educators. Random ideas can be a new way of looking at something, and thereby gain understanding. So I reject that statement.

How are they supposed to know which is good stuff and which is dodgy?

They do it by evaluating it and see if it fits in with what they truly know is correct. Then ask questions about what they do not understand about the idea or concept.

You are using the wrong definition of a quantity that is well defined. The definition of the Volt does not include any reference to area or volume. That is your error. Why persist in it?

You made that point in post #14. I answered it is post #15. Now it is up to you to counter my answer from post #15.

As the one who is proposing an alternative definition, it is up to you to justify it - as with all 'alternatives' to mainstream knowledge. I can only say that I have never read anything so whacky. All you need to do is give a simple link / reference to some supporting evidence.

Not an alternative definition. A complementary definition. I have justified it. What is whacky about it? You have never described why, other than you have never thought of it. It is based on the universally accepted units of voltage.

There is just one definition of voltage and it involves Energy and Charge. I notice, you haven't ever suggested a way of actually working out Voltage with your alternative definition. I think it would be reasonable to expect a bit of Maths to support your new definition.

The definition is complementary to the old definition, so the math from the old works the same.

What sort of touchstone is that? How would he know whether or not he actually got the correct idea from what you have written - except by being given some supporting evidence? You could give someone a very convincing story about the Moon being made of green cheese and they might accept it. That would not make it true.

The object of the question is understanding. Once he understands something, then he can evaluate and determine if is right or wrong.

Ratch
 
  • #31
sophiecentaur,

My quote from earlier on:

Voltage has nothing to do with how many charges there happen to be - unless you are specifically referring to a 'charged' object or a distribution of charge - but that is different (in different Units) from your "Energy Density" idea. You can produce a very high voltage by electromagnetic induction with very small currents (moving charges) or produce massive numbers of moving charges with a very small voltage.

I think you were in self defence mode at the time and ignored this.

I thought it was irrelevant and ignored it.

You seem to be confusing cause and effect here: The induced emf is what causes the charges to move and not due to the charges. Charges don't move without an emf to make them move.

Isn't that what I said in post #27?

The induced Voltage is there whatever resistance the conductor has - the field is there (Volts per metre), even in empty space.

No, the magnetic field intensity units are amps/meter. It is not a electrostatic field.

Ratch
 
  • #32
milesyoung,

Lets say there's no conductor present, only a time-varying magnetic field.

OK, you set up the conditions, now what is the question?

Ratch
 
  • #33
I think OP's last question was this:
remedemic said:
Thanks for the help gentlemen, I can understand voltage alone now, however, I'm having a bit of trouble relating it to resistance at this point.

From what I am reading, a resistor decreases the amount of energy per charge (by converting it into heat or motion through friction), which seems that by definition, voltage would decrease after a resistor, but according to V=IR, and I being constant, voltage goes up?

Could someone clear this confusion up? Thanks again.

I think maybe you are confusing potential with voltage. It is important to be precise in terminology else we miss these little distinctions.

Let's parse your question:
From what I am reading, a resistor decreases the amount of energy per charge (by converting it into heat or motion through friction),
exactly right. It converts potential energy into heat.

which seems that by definition, voltage would decrease after a resistor,
Recall voltage is potential difference .
You didn't say in above phrase where your voltmeter is connected.
Your charge exits the resistor with less energy than when it entered .
Whether your voltmeter shows an increase or decrease depends on where in the circuit its two leads are connected.

but according to V=IR, and I being constant, voltage goes up?
Those words do not paint a picture in my alleged brain. Voltage from where to where goes up?
What V=IR is telling you is this:
>>>It takes more volts to push an amp through some ohms of resistance than through zero ohms of perfect conductor.<<
More precisely, it takes one volt to push one amp through each and every ohm.
Again, Whether your voltmeter shows an increase or decrease depends on where in the circuit its two leads are connected.

It is helpful when first starting out to imagine yourself inside the circuit drifting along with the charges, feeling the "push" of voltage just as the charges do. It'll help you keep polarities straight.
Schematics used to be drawn with positive on top and negative on bottom. It helped with that imagination business, for rising potential moves you "up" (the page), just as with gravity.

Resistance is as you said like friction against current.
It's measured in "ohms", an ohm being the amount of friction which, with one volt across it, allows one amp to pass.

We electricals have a secret - by choosing our units and including in them necessary conversion factors, they come out already metric.
Get these definitions down pat and you'll be a long way ahead:
Coulomb, Joule, Volt, Ampere, Ohm, Watt.
Then you'll be ready for Kirchoff's Laws and circuit analysis.

old jim
 
  • #34
Jim
Uphill and downhill is definitely the way to go on (simple) circuit diagrams, whenever you can. "We electricals" were lucky with our units because nothing electrical ever had anything to do with a King's thumb or how much hay a man could carry. We had a clean sheet in the realtively modern age 'we' started in business.

My view on matters electrical is that you can't expect to 'understand' them. The best you can do is to follow the rules and, in the end, get so familiar with them that they are as much second nature as Newton's laws of motion. And, we have to remember that we were not born with Newton's laws hard-wired into our brains; we had to learn about them too.
Grumpy old devil as he was, Feynman had it right when he took that journalist to task to ask the "why' question about magnetism. Anyone who wants to come to terms with what I'm saying should watch that video. Then they must settle down and learn their basics - by rote at first, if you like. You emerge the other side a lot wiser, more capable and less likely to make up and talk nonsense.
 
  • #35
Ratch said:
I thought it was irrelevant and ignored it.

...

No, the magnetic field intensity units are amps/meter. It is not a electrostatic field.

Ratch
What has that to do with the induced Electric Field? Not all electric fields are "Electrostatic". Are you still saying that comment was 'irrelevant? You have been asked the question by someone else now - with no answer. You response to the question was just to sidestep the issue instead of answering the implied question.

But you could clear this up with just a smidgin of Maths (if it's as simple as you say.). You are still avoiding it and just hand waving. You could, for example, start with Maxwell's Equations, (believed and respected by both of us, I hope), which would take you most of the way there. Just slip in your modification in a valid way, where appropriate and we'd be cooking on gas. Even I would believe you, then.
 
<h2>1. What is voltage?</h2><p>Voltage is a measure of the potential energy difference between two points in an electrical circuit. It is often referred to as "electrical pressure" and is measured in volts (V).</p><h2>2. How is voltage different from current?</h2><p>Voltage and current are two different characteristics of electricity. While voltage measures the potential energy difference, current measures the rate at which electricity is flowing. Voltage is analogous to the pressure of water in a pipe, while current is analogous to the flow rate of water through the pipe.</p><h2>3. What is the relationship between voltage and resistance?</h2><p>According to Ohm's Law, the relationship between voltage (V), current (I), and resistance (R) is V = I * R. This means that as the resistance increases, the voltage needed to maintain the same current also increases.</p><h2>4. How does voltage affect the performance of electronic devices?</h2><p>Voltage is a crucial factor in determining the performance of electronic devices. If the voltage is too low, the device may not function properly, and if the voltage is too high, it can cause damage to the device. Therefore, it is important to use the correct voltage for each electronic device.</p><h2>5. What are some common sources of voltage?</h2><p>There are many sources of voltage, including batteries, power outlets, generators, and solar panels. In most cases, voltage is created by converting some form of energy (such as chemical, mechanical, or solar energy) into electrical energy.</p>

1. What is voltage?

Voltage is a measure of the potential energy difference between two points in an electrical circuit. It is often referred to as "electrical pressure" and is measured in volts (V).

2. How is voltage different from current?

Voltage and current are two different characteristics of electricity. While voltage measures the potential energy difference, current measures the rate at which electricity is flowing. Voltage is analogous to the pressure of water in a pipe, while current is analogous to the flow rate of water through the pipe.

3. What is the relationship between voltage and resistance?

According to Ohm's Law, the relationship between voltage (V), current (I), and resistance (R) is V = I * R. This means that as the resistance increases, the voltage needed to maintain the same current also increases.

4. How does voltage affect the performance of electronic devices?

Voltage is a crucial factor in determining the performance of electronic devices. If the voltage is too low, the device may not function properly, and if the voltage is too high, it can cause damage to the device. Therefore, it is important to use the correct voltage for each electronic device.

5. What are some common sources of voltage?

There are many sources of voltage, including batteries, power outlets, generators, and solar panels. In most cases, voltage is created by converting some form of energy (such as chemical, mechanical, or solar energy) into electrical energy.

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