There will always be inductance. Therefore the current must start from zero when the circuit is completed.

 

‘Which comes first’
At the infinite extremes, one can exist without the other. At any other point, they exist together. If the voltage of a battery drives current through several devices, the voltage across those devices is a result of the current flow. They co exist.
Which came first, energy or matter?

 

Consciousness came first.
Which is a completely separate subject,
and much different than Matter, Energy, Space, or Time.

Consciousness is "Cause".
Matter, Energy, Space, and Time, are the products of Cause.
.
.
.

 

‘Which comes first’
At the infinite extremes, one can exist without the other. At any other point, they exist together. If the voltage of a battery drives current through several devices, the voltage across those devices is a result of the current flow. They co exist.
Which came first, energy or matter?

Voltage "as a result of the currenrt flow"?
Question: In this case, can you explain which force within the conductive part is responsible for the movement of charges which form the current (if not the E-field caused by the voltage) ?

 

Ah, but how is that current started?

Dont know but is that important? We could ask the same about a battery with no load how did the voltage get there in the first place.

 

When I bump a ball (mechanical impulse), is there any delay between impulse and movement of the ball?
I don't know - it is even unimportant for our question, because it is clear:
The mechanical impulse is the cause for the movement of the ball - independently of whether there is a delay or not.

With pure inertia being the only thing keeping the ball from moving, there is no delay. The only thing that can cause a delay is friction.
Push on any mass in deep space and it begins to move immediately. Push it on a surface that has sticking friction (not friction while moving) and it will take some minimum force to get it to start moving.
So something that has no friction moves immediately, while something with sticking friction takes some minimum force before it starts to move.

But i am still waiting for that number for the delay in current when a voltage is applied. I'll read the other posts now in case you replied again though.

 

A battery only "retains" a Voltage-Potential-Difference between it's Terminals, sort of like a spring, it doesn't "do" anything else.
A Battery can not "Produce" Current,
Current "may" "occur" if a Conductive-Path is provided between it's Terminals.

Current is a measurement of how fast a "Voltage-Difference" between 2 points
is trying to equalize it's self back to zero difference.
.
.
.

Well these statements still sounds like 'after the fact' observations. We cant use Ohms Law to prove anything because that is symmetrical with respect to current and voltage (as to their existence).

 

With pure inertia being the only thing keeping the ball from moving, there is no delay. The only thing that can cause a delay is friction.
Push on any mass in deep space and it begins to move immediately. Push it on a surface that has sticking friction (not friction while moving) and it will take some minimum force to get it to start moving.
So something that has no friction moves immediately, while something with sticking friction takes some minimum force before it starts to move.

But i am still waiting for that number for the delay in current when a voltage is applied. I'll read the other posts now in case you replied again though.

You might want to watch this video:

 

This question cannot be answered without a definitive definition of "current".

Voltage is a separation of charge...but you need current to separate that charge. (movement of charge)

But many will argue that the movement of electrons that develop a voltage does not always constitute a current. (example: in the case of photovoltaic)

So, if "current" is only the movement of charge caused by voltage...then voltage has to come first, but if current can be the movement of charge by any means, then current can come first.

If anyone has seen the lightning in a volcano plume, those charges were separated by friction, so the question...does separation of charge by friction constitute "current"?

Well we are not asking about how friction can cause a current flow or not.

What i would like to see is some actual proof that either one comes 'first', and the word "first" implies a time difference. That time difference is called a 'delay', and nobody seems to have provided what that delay is for either V before I or for I before V. IF the delay is zero, then they occur simultaneously which follows from Maxwells equations for fields.

Recall that a pure inertia (mass) does not pose a delay for a force. As soon as the force is applied, the mass beings to move, no delay. If there was a delay, then we would have to explain what that mechanism actually is. For example, if we add sticking friction then we see a delay while the force builds up to the point where the sticking friction is overcome.

The analogy to the electrical circuit comes when i asked for this delay, or at what voltage level would cause (for example) one trillionth of one trillionth of one trillionth of an amp to flow.
But really i guess it would be what voltage level would cause one unit of charge to move. I think we can all answer that numerically, but that would still be after the fact. The real question is what voltage level does it take for one unit of charge to START to move.

So if we apply a voltage like 1 volt at time t=0, at what time does the current start to flow. Is ti 1ms, 1us, 1ps, etc. If there is a delay then we should be able to either measure it or bring in some theory that would tell us.
Of course if current comes 'first', then we should be able to do the same.

 

You might want to watch this video:

Could you please summarize the point of that video?

 

With pure inertia being the only thing keeping the ball from moving, there is no delay. The only thing that can cause a delay is friction.
.....................
But i am still waiting for that number for the delay in current when a voltage is applied. I'll read the other posts now in case you replied again though.

I must admit that I do not know why you have introduced the question of delay into the dicussion.
We spoke about current and voltage - and in this context I do not care about delay yes or no.
I am afraid that we are leaving the actual topic (cause and effect).
(The mechanical example I have mentioned should only show that simultaneousness cannot help for answering these cause-and-effect questions).

 

Could you please summarize the point of that video?

Motion of solid objects propagates at the speed of sound in the material of the object. It is not instantaneous, and very much like the propagation of current in a conductor which happens at the velocity factor of the conductor.

Motion is not instantaneous. Current flow is also not instantaneous. It‘s a propagation which happenes in finite time.

To make the claim of simultaneity you’d have to assert that current is the cause of voltage but that’s not supportable. Volatge is potential, current is a actual.

I honestly believe this is one of those philosophical questions that is a phantom caused by the limits of human language. We invisibly conflate the denotations and connotations of words that in one case are technical terms with severely circumscribed semantics while in another are everyday speech with fast and loose connotations sometimes even superseding the denotation of the word we’d find in a dictionary.

I think this is akin to writing poetry about physics which might be fun but it doesn‘t have any utility in understanding physics. It’s more like an exploration of human cognition and language.

As I tried to point out earlier, if we are careful about the terminolgy, it is more clear. “Voltage” has two meanings that are related but distinct. One is the measurement in volts of the electrical potential between two bodies due to the difference in the number of electrons in each.

We have no way to measure this potential without causing current to flow, but it is only our attempts to quantify potential that leads to the necessity to attach it to current. The potential exists whether we measure it and therefore. “convert” it to this meaning of voltage or not.

The other meaning of voltage is to the unmeasured electrical potential existing between the two bodies. Our measurement does not create it, in fact, it necessarily sacrifices some portion of it in a destructive test to quantify it. It is not creation but destruction.

So, if we use the term potential rather than voltage it seems abundantly clear that potential is a thing while current is an action. When we connect two bodies with electrical potential between them, current flows in order to balance the charge between them. Would you say that when a resevoir’s floodgates are opened the current of the water is creating gravity?

The objection that current can create potential is a red herring. The current that creates that potential was first caused by some other potaential, and, in fact some of the potential in that exchange will be lost as heat.

 

Well we are not asking about how friction can cause a current flow or not.


What i would like to see is some actual proof that either one comes 'first', and the word "first" implies a time difference. That time difference is called a 'delay', and nobody seems to have provided what that delay is for either V before I or for I before V. IF the delay is zero, then they occur simultaneously which follows from Maxwells equations for fields.


Recall that a pure inertia (mass) does not pose a delay for a force. As soon as the force is applied, the mass beings to move, no delay. If there was a delay, then we would have to explain what that mechanism actually is. For example, if we add sticking friction then we see a delay while the force builds up to the point where the sticking friction is overcome.


The analogy to the electrical circuit comes when i asked for this delay, or at what voltage level would cause (for example) one trillionth of one trillionth of one trillionth of an amp to flow.

But really i guess it would be what voltage level would cause one unit of charge to move. I think we can all answer that numerically, but that would still be after the fact. The real question is what voltage level does it take for one unit of charge to START to move.


So if we apply a voltage like 1 volt at time t=0, at what time does the current start to flow. Is ti 1ms, 1us, 1ps, etc. If there is a delay then we should be able to either measure it or bring in some theory that would tell us.

Of course if current comes 'first', then we should be able to do the same.

Moving an electron from one point to another requires ENERGY. Exceed the amount required to bridge the gap between the two and it begins to "flow". This can be in the form of a simple unidirectional spark or, in the case where a conductive path is established between the "opposite poles" of the source and destination, a circuit.

Whether or not this occurs simultaneously just depends on the circumstance. In general if current appears first then we effectively get an "inward" flow of charge. Otherwise the flow of current can be said to be moving "outward".

There can also be voltage but no current. Two charged rods separated in space by some distance will only experience a flow in charge (ie: current) if they are brought close enough together.

You can also have current but no voltage. An electron fired from a cathode ray tube effectively constitutes a flow of current but only implies a voltage difference if the electron collides with a positively charged plate (as a negatively charged plate would have deflected the electron rather than absorb it).

 

Motion of solid objects propagates at the speed of sound in the material of the object. It is not instantaneous, and very much like the propagation of current in a conductor which happens at the velocity factor of the conductor.

Motion is not instantaneous. Current flow is also not instantaneous. It‘s a propagation which happenes in finite time.

To make the claim of simultaneity you’d have to assert that current is the cause of voltage but that’s not supportable. Volatge is potential, current is a actual.

I honestly believe this is one of those philosophical questions that is a phantom caused by the limits of human language. We invisibly conflate the denotations and connotations of words that in one case are technical terms with severely circumscribed semantics while in another are everyday speech with fast and loose connotations sometimes even superseding the denotation of the word we’d find in a dictionary.

I think this is akin to writing poetry about physics which might be fun but it doesn‘t have any utility in understanding physics. It’s more like an exploration of human cognition and language.

As I tried to point out earlier, if we are careful about the terminolgy, it is more clear. “Voltage” has two meanings that are related but distinct. One is the measurement in volts of the electrical potential between two bodies due to the difference in the number of electrons in each.

We have no way to measure this potential without causing current to flow, but it is only our attempts to quantify potential that leads to the necessity to attach it to current. The potential exists whether we measure it and therefore. “convert” it to this meaning of voltage or not.

The other meaning of voltage is to the unmeasured electrical potential existing between the two bodies. Our measurement does not create it, in fact, it necessarily sacrifices some portion of it in a destructive test to quantify it. It is not creation but destruction.

So, if we use the term potential rather than voltage it seems abundantly clear that potential is a thing while current is an action. When we connect two bodies with electrical potential between them, current flows in order to balance the charge between them. Would you say that when a resevoir’s floodgates are opened the current of the water is creating gravity?

The objection that current can create potential is a red herring. The current that creates that potential was first caused by some other potaential, and, in fact some of the potential in that exchange will be lost as heat.

I think there is some confusion as to what i mean when i say simultaneous.

I am not saying that current reaches it's highest point instantaneously. I am saying that current STARTS to flow as soon as voltage is applied. It is the start point, at t=0, that i am talking about, not 1ps later or 1us later although we could look at that too.

But the for the views that there are times when there is a delay i still dont see any numbers of what theat delay is or how to calculate it. That's because apparently nobody here can state that.

BTW a bar or rod of metal that is struck on one end is a transmission line. To see what is happening it depends on how far down the line you look. In this highly physical case we would be looking right at the interface between hammer head and end of rod, at the very moment of first contact.
So the application of force does not occur until the hammer head meets the metal, which is analogous to when the voltage is first applied to a circuit.

There is an article on the web that talks about Maxwells equations and the simultaneity issue but i have yet to find it again. But there is nothing there that suggests that there is any delay. if there was, we could calculate it right now.

I am starting to think now though that some people will never grasp this concept i think because many of us are so used to using voltage supplies vs current supplies. With a voltage supply you get the general impression that you are initiating something when you apply a voltage and i think that carries over to what we call human experience. We experience things that are not true and quantum mechanics makes this ever so clear now.

I'll read the other posts now and thanks to everyone who is participating, and i will try to find some articles that talk about the simultaneity issue between voltage and current.

 

Moving an electron from one point to another requires ENERGY. Exceed the amount required to bridge the gap between the two and it begins to "flow". This can be in the form of a simple unidirectional spark or, in the case where a conductive path is established between the "opposite poles" of the source and destination, a circuit.

Whether or not this occurs simultaneously just depends on the circumstance. In general if current appears first then we effectively get an "inward" flow of charge. Otherwise the flow of current can be said to be moving "outward".

There can also be voltage but no current. Two charged rods separated in space by some distance will only experience a flow in charge (ie: current) if they are brought close enough together.

You can also have current but no voltage. An electron fired from a cathode ray tube effectively constitutes a flow of current but only implies a voltage difference if the electron collides with a positively charged plate (as a negatively charged plate would have deflected the electron rather than absorb it).

Yes that energy part is what i have been pushing here. You cant do anything without applying some energy, at least in the classical world. In a normal electrical circuit, that requires BOTH voltage AND current (if we are using only electrical quantities which is the point of this discussion).

Imagine what would happen if a voltage could "DO" something all on it's own. Then Ohms Law;
P=V*I=0 but yet something moves. That's impossible in the classical world.
A capacitor:
E=(1/2)*C*V^2
shows energy stored in a capacitor, and that is fine because there is no attempt to initiate current flow without adding another component of some type.
An inductor:
V=L*di/dt
It is true that if we have no voltage we have no change in current, but also true that if we have no change in current we have no voltage.

 

Current First. Voltage can exist without current. But current cannot occur without voltage

 

I must admit that I do not know why you have introduced the question of delay into the dicussion.
We spoke about current and voltage - and in this context I do not care about delay yes or no.
I am afraid that we are leaving the actual topic (cause and effect).
(The mechanical example I have mentioned should only show that simultaneousness cannot help for answering these cause-and-effect questions).

I explained that. You said that current comes "after" voltage but you cant not explain exactly why that is so. In seeking a delay, that must be present because "after" implies a time difference.
If i say pulse 2 comes "After" pulse 1, you know that the rise of the two pulses do not occur at the same time and that means there MUST be a delay.

So if you can explain your point then you have to specify something that we can use to calculate something that causes current to come "after" voltage is applied. I suggested a delay parameter because that is how we measure things that come 'after' other things.

Show me an experiment that shows that current comes after voltage.

 

Current First. Voltage can exist without current. But current cannot occur without voltage

So you are saying that current would always occur before voltage?

 

Hello again,

Here is another way of looking at this.
If voltage came before current, how would we measure this phenomenon?
Keep in mind we are not talking about having a battery on hand at t=0 and then later at t=10 seconds we connect the battery to a resistor and then see current flow and then state that it took 10 seconds for current to flow. The point is what happens at the instantaneous time point when the voltage supply first meets the resistor.

If this is true, then we should have a formula to explain the mechanism behind this.

 

I explained that. You said that current comes "after" voltage but you cant not explain exactly why that is so. In seeking a delay, that must be present because "after" implies a time difference.

Sorry - but you have quoted me wrong! Where did I use the term "after"?
In contrary - In my post#20 I wrote:
"Additional remark: I think, the title of this thread is somewhat misleading (...which occurs first?):
According to my interpretation, the word "first" does not apply to a timely sequence (delay between some occurences) but to the "cause-and-effect" problem. "

Added (later):
This thread is the follower of the following
https://forum.allaboutcircuits.com/posts/1708446/
in which we have dicussed (among other items) the question if a current could create a voltage (or if a voltage is always necessary for driving a current) .
As we can see - it was YOU (in post #43 of this foregoing thread) who has created this new thread with the wordings " .....occurs first? ".
So - you have invented the timely sequency into the subject of discussion.