Elementary Electricity

[Turtle]

Thank you Turtle!:evil:

I think now I can link current with parallel analogy. At the point of seapartion of two pipes from a single pipe, the cross-section would change- I am slightly confused it would be a increase or decrease. Consequently, the amount of water flowing or current flowing would also change.

Clear up to this. But here again the problem starts.:phones:

When we press the pipe acting as reistors, the water pressure or P.D would increase. But P.D remains same in a parallel connection.

Again , help! help!

 

This is where the analogy starts breaking down, because electricity is not a fluid. I think in a pipe with water the resistance is found in the roughness of the pipe interior, and the rougher a pipe interior, the higher the resistance and there is actually a drop in pressure.

 

In Ohm's law, I = V/R, if the voltage V remains constant, the current/amperage I drops with an increase in resistance R.

 

I better stop there before I blow a fitting. :thumbs_up Hope I didn't make things clear as mud. :rolleyes:

[Mohit Pandey]

This is where the analogy starts breaking down, because electricity is not a fluid. I think in a pipe with water the resistance is found in the roughness of the pipe interior, and the rougher a pipe interior, the higher the resistance and there is actually a drop in pressure.

No, the pressure increases. That is why in kidney, the water is filtered by increasing pressure. This is done by transporting blood from a thick pipe to a thin pipe. It was told by my teacher . However,I could not found it on Google and therefore, I can't give you the link.

 

In Ohm's law, I = V/R, if the voltage V remains constant, the current/amperage I drops with an increase in resistance R.

 

I better stop there before I blow a fitting. ;) Hope I didn't make things clear as mud. ;)

I could not understand the bold words as Ampere is the unit of current.

I think you need to blow not a fitting, but many fittings.:eek:

[Mohit Pandey]

Even though my second question has not answered yet, I asking the third.;)

In Indian domestic electric circuit, there are three types of wires- earth, live and nuetral.

In India, the potential difference between the nuetral and live wire is 220 V. However, P.D is needed for the current to flow in an electric circuit. And here, isn't the wires different and therefore, shouldn't the P.D be between the beginning and the end of ciruit?

Electrical wiring (UK) - Wikipedia, the free encyclopedia

[Turtle]

No, the pressure increases. That is why in kidney, the water is filtered by increasing pressure. This is done by transporting blood from a thick pipe to a thin pipe. It was told by my teacher . However,I could not found it on Google and therefore, I can't give you the link.

 

Well, cardio plumbing is yet again moving the analogy even further from electricity. But I'm not a doctor, I'm a plumber. Here's some interesting reading on rough pipe: >> Transport Phenomena: A Unified Aprroach - Google Book Search

 

I could not understand the bold words as Ampere is the unit of current.

I think you need to blow not a fitting, but many fittings.:eek:

 

I only meant to show the terms are referring to the same condition.

Many fittings blown yes. :D

 

Even though my second question has not answered yet, I asking the third.

In Indian domestic electric circuit, there are three types of wires- earth, live and nuetral.

In India, the potential difference between the nuetral and live wire is 220 V. However, P.D is needed for the current to flow in an electric circuit. And here, isn't the wires different and therefore, shouldn't the P.D be between the beginning and the end of ciruit?

 

The neutral & ground circuits are essentially the same. The neutral circuit is the term for ground leads at the generator and along the transmission lines; typically the white wire in buildings in US. The ground circuit in a particular structure has an on-site connection to ground, either through a grounding rod pounded 5+ feet into the ground, or buried metal water lines. The local ground gives a direct unimpeded open path to discharge surges within the structure, which also keeps these surges off the grid via the neutral lead. ;): ;)

[snoopy]

To understand the concept properly I have used the analogy of flow of water in a pipe and the resistors are obstructing the flow of water. I have attached the pictures of the two combinations which is being formed in my mind while talking about it. The pipes symbolise conductors.

:confused:

 

 

Its better to avoid using water as an analogy, electricity is a potential energy like raising a ball above your head and letting it drop, but of course there are lots of electrons not just one of them being produced but if you can imagine marbles being dropped through plastic tubes this is better the larger the tube the less resistance it has and the more marbles or electrons go through ie the current is greater remember

 

[math] I = \frac{V}{R} [/math]

 

the smaller the tube the greater the resistance and less marbles or current goes through.

 

If you can get away from water and use this analogy instead things become clearer.

 

Peace

:)

[snoopy]

QUESTION

Welcome back!:shrug:

Magnetic Fields and Currents - Picture - MSN Encarta

At the centre of the circular loop, the arcs of the concentric circles representing magnetic field lines appear as straight line.

That means the field is uniform, doesn't it? Then what special would happen to a particle that is placed there? Would it go in the direction of the straight line at the centre would point for infinite distance?

 

a charged particle would follow the lines of force.

[snoopy]

Even though my second question has not answered yet, I asking the third.:shrug:

In Indian domestic electric circuit, there are three types of wires- earth, live and nuetral.

In India, the potential difference between the nuetral and live wire is 220 V. However, P.D is needed for the current to flow in an electric circuit. And here, isn't the wires different and therefore, shouldn't the P.D be between the beginning and the end of ciruit?

Electrical wiring (UK) - Wikipedia, the free encyclopedia

 

No in electrical engineering current is produced by the voltage being out of phase (ac)

 

So in ac a current can flow between two live conductors as long as they are out of phase with each other creating a potential difference.

 

imagine two sine waves out of phase with each other.

[Turtle]

Its better to avoid using water as an analogy, electricity is a potential energy like raising a ball above your head and letting it drop, but of course there are lots of electrons not just one of them being produced but if you can imagine marbles being dropped through plastic tubes this is better the larger the tube the less resistance it has and the more marbles or electrons go through ie the current is greater remember

 

[math] I = frac{V}{R} [/math]

 

the smaller the tube the greater the resistance and less marbles or current goes through.

 

If you can get away from water and use this analogy instead things become clearer.

 

Peace

:)

 

Where is the voltage represented in the marble analogy? As far as the current part, you simply substituted one measure of volume, the marbles that will fit in the pipe, for another, the water that will fit in the pipe. I see some problem too with the acceleration due to gravity changing with the length of the gedanken marble pipe, especially if that is the analogous voltage component.

 

Both analogies suffer because they have physical particles traveling the length of the conductor representing the electrons that do not travel the length of the conductor.

[snoopy]

Where is the voltage represented in the marble analogy? As far as the current part, you simply substituted one measure of volume, the marbles that will fit in the pipe, for another, the water that will fit in the pipe. I see some problem too with the acceleration due to gravity changing with the length of the gedanken marble pipe, especially if that is the analogous voltage component.

 

Both analogies suffer because they have physical particles traveling the length of the conductor representing the electrons that do not travel the length of the conductor. :shrug:

 

 

The voltage is represented by how high you hold the marbles from the ground.

 

The analogy is not perfect its just better than water.

 

Peace :)

[Turtle]

The voltage is represented by how high you hold the marbles from the ground.

 

The analogy is not perfect its just better than water.

 

Peace :)

 

As I say, the acceleration due to gravity, 32 feet/second/second, is never constant and so a poor representation of voltage imho. At least the water analogy allows a constant pressure to relate to a constant voltage, and the cross-sectional area of the pipe is the measure of volume and so the relation to current.

 

Voltage > how hard you're pushing electrons

Amperage > how much/many electrons you're pushing

 

Oui/no? :shrug:

[snoopy]

As I say, the acceleration due to gravity, 32 feet/second/second, is never constant and so a poor representation of voltage imho. At least the water analogy allows a constant pressure to relate to a constant voltage, and the cross-sectional area of the pipe is the measure of volume and so the relation to current.

 

Voltage > how hard you're pushing electrons

Amperage > how much/many electrons you're pushing

 

Oui/no? :shrug:

 

Im an electrical engineer Turtle so you can think what you like,

Im tired and not going to fight with you over it.

 

In general terms Gravity can be taken as constant on the face of the Earth and for this analogy it has to be.

 

Why the water pressure idea doesnt work is because when you flick a switch the voltage or potential difference falls to zero (like a ball being released hits the ground) in your analogy it never falls to zero.

 

But in general terms of your analogy

Voltage would be water pressure

Amperage or current as we like to call it would be how many.

 

oui mon ami que je donne dedans

 

Paix:)

[Turtle]

Im an electrical engineer Turtle so you can think what you like, Im tired and not going to fight with you over it.

 

As I said, I am a plumber (retired), and I'm not fighting; I'm learning about mistakes in analogies and trying to clarify the statements for Mohit when he reads them.

 

...Why the water pressure idea doesnt work is because when you flick a switch the voltage or potential difference falls to zero (like a ball being released hits the ground) in your analogy it never falls to zero.

 

Except when you close valves. This is the reason, by the by, that early thermionic tubes were referred to as valves, as they controlled the flow of a current. I was raised by an electrical engineer. :shrug:

[Mohit Pandey]

No in electrical engineering current is produced by the voltage being out of phase (ac)

 

So in ac a current can flow between two live conductors as long as they are out of phase with each other creating a potential difference.

 

imagine two sine waves out of phase with each other.

 

Hello Snoopy!

 

Sorry, but I am unable to understand you.:eek_big: Moreover, I haven't read about sine waves and phases yet. Can you tell in another way?

And Turtle's reply also went above my mind. I will try to understand it one more time.

Peace:)

[Mohit Pandey]

a charged particle would follow the lines of force.

Would an iron particle also do the same? Moreover, do you mean to say that charged particle would go for for infinite disatnce in the direction inicated by the direction of line at the centre of circular loop?

[sanctus]

There is exactly one position where it would go to infinite, but it is an instable position, just like trying to make stay a pen in equilibrium on the sharp side. So theoretically it can happen and practically it never does.

[Turtle]

... Turtle's reply also went above my mind. I will try to understand it one more time.

Peace:)

 

By all means ask for any specific clarifications. Worth noting is that my descriptions of the water in the pipe analogy all refer to DC current save for my aside on simulating AC in post #16. :): :shrug:

[snoopy]

Except when you close valves. This is the reason, by the by, that early thermionic tubes were referred to as valves, as they controlled the flow of a current. I was raised by an electrical engineer.

 

Yes this is exactly why its a poor analogy the closing of valves is the exact opposite of flicking a switch to the closed position.

 

Thermionic valves are just diodes, transistors and triodes yes they do control current but they were called a host of names such as vacuum tubes as well I would not get too hung up on the valve thing.