the electron has both voltage and charge

Voltage is not a physical property of an electron. An electron is only associated with voltage when there is a separation of charges. The so-called "electron volt" is a measure of kinetic energy (Joules), not voltage. You can check out what an electron volt is on Wikipedia.

equation of motion tells us that a force moves a mass right away with no delay.

Not true, You are ignoring static friction and elastic modulus. Unless your equation is a step function, any random force does not cause motion. A threshold force is required to overcome static friction. The force will cause some elastic deformation on contact. The whole body will not move until the force deforms the object enough to initiate movement of the body.

We are all guilty of apophenia in every day life

That seems to be true.

 

Of course, the obvious answer is voltage moves the electrons, but it is charge that flows in a circuit, not voltage.
So, at some point that charge must again become voltage.

Did somebody (except you, see the quotation below) state that voltage would flow in a circuit? So what is this sentence about?

May I remind you on your post #112:
"The battery provides the energy to create current, but the voltage in the battery does not flow thru the wires to the resistor. At the resistor a voltage is "developed" by the current.
So the sequence is indeed voltage...current...voltage."

I must admit that - up to now - I never have heard such a "new" explanation: The battery voltage would "create a current" and across the resistor "a voltage" (another one ?) would be "developed by the current".

 

Not true, You are ignoring static friction and elastic modulus.
Unless your equation is a step function, any random force does not cause motion. A threshold force is required to overcome static friction. The force will cause some elastic deformation on contact. The whole body will not move until the force deforms the object enough to initiate movement of the body.
That seems to be true.

Hello again,

With a force and a mass there is no static friction and there is no elastic property and no spring constant.
When you state a "force" and "mass" and do not state anything else in physics, that means a mass that is perfectly solid and does not deform either.
The equation of motion is EXACTLY like a current source in parallel with a capacitor in an electric network.
We could actually add in a spring constant, but the results would be the same and that just complicates matters.

Now, if we add a spring to the mass so the force presses on the spring, doesnt it seem that there would be some delay before the mass moves? Well there isnt and that is how deceptive human experience can be.
Do some research on a spring mass damper system if you like, but that's just complicates it.

Yes you can look at voltage as a difference in the distribution of charge. But we already know that like with a battery and i addressed the battery idea several times in this thread. It's equivalent to the idea that we can not apply a force to a vacuum. If you dont see how this works, i cant help it you are just going to have to try to understand this, sorry about that

 

Did somebody (except you, see the quotation below) state that voltage would flow in a circuit? So what is this sentence about?

May I remind you on your post #112:
"The battery provides the energy to create current, but the voltage in the battery does not flow thru the wires to the resistor. At the resistor a voltage is "developed" by the current.
So the sequence is indeed voltage...current...voltage."

I must admit that - up to now - I never have heard such a "new" explanation: The battery voltage would "create a current" and across the resistor "a voltage" (another one ?) would be "developed by the current".

Ok it's obvious that I can't make my case here.

So, it's time for me to ask you a question...

It is a fact that voltage does not flow in a circuit, you don't have to take my word for that, you can look it up yourself.

So, if you agree that voltage does not flow in a circuit then how does it get to the resistor?

You need not answer that question if you disagree with the fact that voltage does not flow in a circuit.

 

Just to be open here,

voltage and current is just how we measure things,

may be it is not voltage / current,

but there could be another "force" or "forces" at work, that we are not aware of

Which we take as voltage and current ?

Just a thought whilst were tackling all this deep stuff,

 

Ok it's obvious that I can't make my case here.

So, it's time for me to ask you a question...

It is a fact that voltage does not flow in a circuit, you don't have to take my word for that, you can look it up yourself.
So, if you agree that voltage does not flow in a circuit then how does it get to the resistor?
You need not answer that question if you disagree wih the fact that voltage does not flow in a circuit.

I am a bit confused.
In this thread, you were the only one who has used the term "voltage flow" - nobody else!
And now, you are asking ME for a corresponding explanation of this funny term?
Is it really necessary to tell you something about the E-field which is concentrated within the conductor as soon as it is connected to the two voltage terminals?

 

Ok it's obvious that I can't make my case here.

So, it's time for me to ask you a question...

It is a fact that voltage does not flow in a circuit, you don't have to take my word for that, you can look it up yourself.

So, if you agree that voltage does not flow in a circuit then how does it get to the resistor?

You need not answer that question if you disagree with the fact that voltage does not flow in a circuit.

That's another interesting angle. If i understand you right, you are saying that since voltage does not flow it can not get anywhere by itself it must be placed there artificially, and so before it is placed there it is not doing anything.

This may be similar to what i was saying about a 'force'
You can not push on a vacuum with a force, therefore whatever is being used to 'apply' the force does not do anything until the moment of contact with a mass. What is more is that since that 'force' will have to come from some other object, that object must be already moving before it touches the mass for the very first time.
So it appears that there is a conceptual difference between applying a force and noticing that the force interacts with the mass. We apply a force and so we can say that 'we' caused something to happen, but the way the force interacts with the mass is not the same the force and the mass interact simultaneously so there is nothing that came first or second. The force and the movement are somehow tied together you cant have one without the other.

 

The force you might be talking about is electromotive force from Faraday's Law. An E field must be applied for the current to flow. This current and resulting voltage drops may occur simultaneously but its not instantaneous. The step needs time to propagate
We must consider di/dt and dv/dt for inductors and capacitors. They are not in phase.

 

Apologies if I've been ill mannered, I'm going through a terrible cold and still working through a challenging math class.

 

No short cuts to math I’m afraid, but we’re off topic.

How to reconcile the electromagnetic aspect of voltage and current?

 

The force you might be talking about is electromotive force from Faraday's Law. An E field must be applied for the current to flow. This current and resulting voltage drops may occur simultaneously but its not instantaneous. The step needs time to propagate
We must consider di/dt and dv/dt for inductors and capacitors. They are not in phase.

Apologies if I've been ill mannered, I'm going through a terrible cold and still working through a challenging math class.

Hello again,

No problem i understand i am going through something similar but i did get tested and found i dont have covid. I do have a slight cough though and it makes it hard to fly due to the other passengers might get upset if they hear someone coughing or sneezing. Covid phobia.

The thing is, although the electromotive force is deemed "a force" it is not actually a force. It is simply It is measured in volts, and that is equivalent to one joule per coulomb of charge. Isnt that interesting how charge got into the definition?
Unfortunately, the nomenclature from the past called it a force probably because it can be thought of as a force, and that is just the human interpretation for ya again. Gravity can also be though of as a force because of the way things react to gravity, but we know that gravity is a property of spacetime.

So as to the electric field starting current flow, that's not possible. For one thing, it will be accompanied by a magnetic field and the magnetic field is what we can call the force behind the movement. So we are right back to the force and the mass analogy.

The AC circuit is a little more difficult to analyze, but not that much more. The first thing we would look at in the context of this thread is not the AC response itself but the exponential part of the response. That is what happens at the very first instant of application of any voltage or current. It could also just be a ramp though but in either case we see about the same thing.

Here is the complete time response to an RC circuit with output voltage measured across C and driven by a sine source:
Vc(t)=(w*C*R*%e^(-t/(C*R)))/(w^2*C^2*R^2+1)-(w*cos(t*w)*C*R)/(w^2*C^2*R^2+1)+sin(t*w)/(w^2*C^2*R^2+1)

and driven by a cosine source:
Vc(t)=-%e^(-t/(C*R))/(w^2*C^2*R^2+1)+(w*sin(t*w)*C*R)/(w^2*C^2*R^2+1)+cos(t*w)/(w^2*C^2*R^2+1)

If we make R=C=w=1 we end up with:
Vc(t)=sin(t)/2+cos(t)/2-%e^(-t)/2

and you can see this exponential part clearly having an effect at the start of the response.

Hope this helps and that you get over your illness soon too.

 

Little update.

As i always like to say, distance (length) is one of the most important parameters in the universe, second only to maybe energy, although the two are related. As we look at things from afar, they look like one thing because the smaller things can not be distinguished. As we get closer, we see the smaller things, but then as we get even closer we see even smaller things, and this is a major paradigm in physics ... a belief (and actually truth in many circumstances) that as we look closer and closer we see smaller and smaller things. This is part of the drive of physics research.
Now that may change in the future, but for now it still seems like a valid way to look at nature except in some extreme cases. For example, if we were talking about a proton instead of an electron when we deal with protons we can deal with them as one single object in many cases. Then as we look closer we see they are made up of quarks, a smaller thing yet. The difference in these views or those like these is sometimes referred to as the "IR" to "UV" view, which compares their distances to that similar to the wavelength of different light frequencies. When we go from proton to quarks we move from the IR view to the UV view, which of course implies that the distance is a key factor in how we view these things. We look close, we see an object, we look closer, we see it is made of smaller 'objects'.
Now with the electron it's a little different but the length scale idea still applies, where if we need to see more detail we need to get smaller and we also need to look in shorter time lengths.

So it turns out that when we look at very very small time periods we can see a delay in electrons as their atoms are hit by photons (the photoelectric effect of course) they move, but they dont just move, they wait a tiny tiny fraction of a second. The average delay is 130e-18 seconds, which is so small it is negligible in many circumstances. This was measured using special techniques using lasers.

So for this we see an incredibly small time delay before the electron moves. Why this happens i dont know yet. For an electric circuit, it may be different but maybe it just has not been measured yet. For an applied voltage it may be different because the electric field and magnetic field appear together, or at least that's the current theory.

This is an interesting turn of events, although again we have to stress that the working scale would be down to the UV size analogy so in most cases it wont matter anyway. As quantum devices come about more and more with wider and wider applications, we may see this tiny delay actually affect some measurements and so there may be a tiny tiny delay yet to be discovered in the case of the electronic circuit too.

 

@MrAl - I've been thinking about this and we like the cause and effect approach of thinking about our circuits. "I placed a voltage and current starts to flow, I have a current so voltage can be developed". But in actuality I believe that we are talking about two sides of the same coin. They are definitely properties which can be measured (usually by converting one to the other). You cannot have a voltage without current or current without voltage. It would be like saying width of a rectangle can exist without the length... it would be a line not a rectangle.

 

@MrAl - I've been thinking about this and we like the cause and effect approach of thinking about our circuits. "I placed a voltage and current starts to flow, I have a current so voltage can be developed". But in actuality I believe that we are talking about two sides of the same coin. They are definitely properties which can be measured (usually by converting one to the other). You cannot have a voltage without current or current without voltage. It would be like saying width of a rectangle can exist without the length... it would be a line not a rectangle.

Hello there,

Well i am not sure we can say that for each and every voltage and current because there is such a thing as a static quantity and this i believe has been proved and may not be too hard to understand if we just think about charges that are not moving. My approach in this thread is more about moving charges and really how they start to move or what is the mechanism behind this. In electrical circuits we usually see this though and in practice it is very hard to get one without the other because there is always some "leakage" although that leakage may be very small (high quality capacitor, MOSFET gate current, etc.). But in any of those cases my approach is what happens when they change from being static then start to move. It's a very fine point but obviously one that physicists care about or they would have never tried to measure the delay in the photoelectric effect. I'd have to look better but i have a feeling a time of 130 attoseconds means nothing in most electric circuits. That is just an average though and depends on the angle of incidence so it could be greater although i dont have a number yet on what the maximum delay could be.

Just to note...
I made a tiny error in my writeup in my previous post but corrected it now. I believe the light hits the atom then an electron responds i dont think it actually hits the electron. I think the atom acts as a whole when the energy increases then it has to release some and it probably depends on which electron is the most free at the time and maybe in the best position to move.

Now back to the question of the delay in the electric circuit itself, i still dont think there is any delay because the mechanism for current flow in an electric circuit is different than the photoelectric effect. Now this is not to say that somewhere up or down the wire far from the application point there may be and most likely is a delay because although it is an electrical circuit in the form of a transmission line the speed of light also comes into play because of the setup time of the fields. With zero distance though the speed of light doesnt matter.

I guess we also have to always keep in mind that whatever we figure out it's just going to be an analogy of how nature really works. Quantum mechanics may be i better way to look at all this, but it's still an analogy to what is really happening and it may take many years to figure out how everything really works. IT could turn out that some things are just what we might think of as "mystical" right now and if we dont have the innate ability to understand this there is a chance we never will.

 

Just curious, does voltage exist at absolute zero?
Does this make sense?
Let H = heat (temperature)
\[ H= I^2R*t \]
\[ H= (V^2/R)*t \]
\[ V^2/R= H/t \]
\[ V=sqrt((H/t)*R)\]

 

Just curious, does voltage exist at absolute zero?
Does this make sense?
Let H = heat (temperature)
\[ H= I^2R*t \]
\[ H= (V^2/R)*t \]
\[ V^2/R= H/t \]
\[ V=sqrt((H/t)*R)\]

Well one thing is for sure. There are not many cases where absolute zero actually occurs in the universe. Everything is constantly inundated by countless waves propagating throughout the cosmos, preventing any given particle of matter to be "frozen" at 0 kelvin (which is to say completely free from all vibrations). Aside from fleeting moments of course.

Also your equations are missing Boltzmann's constant. Remember, temperature is not MERELY a measure of the average kinetic energy of a system. There is also an entropy factor involved...

 

Well one thing is for sure. There are not many cases where absolute zero actually occurs in the universe. Everything is constantly inundated by countless waves propagating throughout the cosmos, preventing any given particle of matter to be "frozen" at 0 kelvin (which is to say completely free from all vibrations). Aside from fleeting moments of course.

Also your equations are missing Boltzmann's constant. Remember, temperature is not MERELY a measure of the average kinetic energy of a system. There is also an entropy factor involved...

absolutely right, and everything should be verified by experiment. Sorry to annoy you but I’m just trying to get the relationships correct for visualizing. It’s not for an actual real scenario.

 

Just curious, does voltage exist at absolute zero?
Does this make sense?
Let H = heat (temperature)
\[ H= I^2R*t \]
\[ H= (V^2/R)*t \]
\[ V^2/R= H/t \]
\[ V=sqrt((H/t)*R)\]

Not according to the battery in my car in the winter months

Well i guess we would have to see what is causing that voltage if it exists. If it was a chemical battery we'd probably have to say 'no' as illustrated by the little joke above.

Supposedly current flows freely at 0K with no resistance.