Voltage - Page 2 - Electronic Circuits Projects Diagrams Free

srimannarayanakarthik · 20th July 2006, 03:39 AM

Quote:

Originally Posted by Optikon

OK, here's the strange discussion! (and I can't explain it!)
The person who is driving car 2 does see forward and backward moving cars 1 & 3 from THAT perspective. However, an outside observer sees all three cars moving in the SAME direction.

Now, are you an outside observer (with ammeter in hand!) or are you riding on an electron trying to measure/observe the current?

An electromotive force can "push" an electron. Electrons can push each other due to same charge even though they don't need to "move" very far.
So if it makes sense to you how they can "flow" in one direction in a conductor, then they can also flow the other way.

Here is the collection of smilies apparently available:

:cool:

but if they are movin in either direction then how can say 1 wire as phase and the other as neutral.
and about the ammeter, it too contains coils. so what v measure is just a reference quantity. but not the exact value. so the electrons in the ammeter either vibrate with the same frequency of car2 so that v would be able to meaure the accurate value

**Nigel Goodwin** · 20th July 2006, 08:03 AM

Quote:

Originally Posted by srimannarayanakarthik

but if they are movin in either direction then how can say 1 wire as phase and the other as neutral.

Phase and neutral don't mean anything, they are purely arbitary terms, it's ONLY how the neutral is connected that makes it neutral, and the other phase (or live).

dknguyen · 21st July 2006, 05:00 AM

The voltage difference between the two leads just happens to be the AC sinusoid. In reality, either lead could be whatever voltage you want relative to the surroundings/ground, as long as the voltage difference between the leads always makes a sinusoidal wave.

The neutral just means that one of the leads just happens to be tied to the ground so that it doesn't float around too much. But it doesn't have to be for AC to work.

IN the general case it is not necessary to have a "fixed constant" voltage reference in AC. It's just the difference between the two. You can think of it one of the wires (it doesn not matter which one,) as a reference that changes. Sometimes one is tied to ground which fixes the reference, but again, it's not necessary.

dreadengineer · 30th July 2006, 01:11 AM

I think we should be clear that in AC current, the electrons do actually turn around and flow back the other way. If it doesn't make sense that you can get power out of that, think of it like water in a pipe. If the water flows back and forth, you can still put a propeller in the water, and it will be turned alternately forward and backward, and you can get power from that. The source of the power comes from whoever is pushing the water forward and pulling it back, which is the power company. You can get power from AC current the same way. For example, an AC motor makes the electrons do work as they move forward and again as they move back.
It's probably less confusing to just think of the voltage: the voltage between the two plugs on a power outlet alternates -- first a higher voltage on the right one, then a higher voltage on the left one, and you take that voltage and do something with it.

dreadengineer · 30th July 2006, 01:21 AM

Also, about voltage, like the post above was saying, voltage only has meaning as the RELATIVE voltage between two things. That's how we can say that one wire of the power outlet is neutral: it's held at the same voltage as the ground. So if you touched that wire and touched something that was grounded, like a water pipe, you shouldn't get shocked. But the other wire is going between +120V and -120V relative to ground. So if you touch it and the ground, you will get shocked, because there's a relative voltage. Whenever someone says something is at a voltage, like, "this wire is at 5V" it is implicitly relative to a reference. For example, in a portable device, it's relative to the - terminal of the battery. Saying that the wire is at 5V means it's 5V higher than the - terminal of the battery.

Hero999 · 30th July 2006, 03:33 PM

The -v terminal of the battery is often considered to be the referance point 0V. Dual power supply circuits have the referance point taken between the two batteries.

gokulakannan · 5th August 2006, 10:49 AM

hi i'm a Final year Electrical & Electronic Engineering student like to do a project in Embedded systems i need a sample projects for my reference

mybuickskill6979 · 29th January 2007, 03:26 AM

so the amount of electrons that pass a given point in one second is an amp? and a coulomb? Sweet!!

thats one word that confused me when reading about farads and capacitance!!

Roff · 29th January 2007, 03:51 AM

Quote:

Originally Posted by mybuickskill6979

so the amount of electrons that pass a given point in one second is an amp? and a coulomb? Sweet!!

thats one word that confused me when reading about farads and capacitance!!

An amp is one coulomb per second. The number of electrons in a coulomb is 6.2415*10^18.

ericgibbs · 29th January 2007, 07:36 AM

hi srimannarayanakarthik,

Look at the thread 'electron velocity' download the *.zip posted by luisgerman.

This should help you visualise electron 'movement' in a conductor.

Regards
EricG

mybuickskill6979 · 29th January 2007, 04:29 PM

thats alot of electrons. Thanks Ron.

Sceadwian · 30th January 2007, 01:16 AM

You should try calculating the amount of electron motion that occurs for a thousand watt space heater benig on for 8 hours.

ikalogic · 22nd March 2007, 10:20 PM

i like this analogy between hydraulis and electricity

OutToLunch · 23rd March 2007, 01:38 PM

i don't remember the specifics anymore, but in a system dynamics class in college, we took mechanical systems and translated them to an 'equivalent' electrical circuit and would use that to predict response. i remember having to do a project where the response of a car was found in relation to the tire hitting a bump in the road. The mass translates to inductance, Springs translate to capacitors and the shocks (dashpots) translate to resistors.

Hero999 · 23rd March 2007, 01:51 PM

Sounds like LRC circuits and second order differential equations, I was never any good at that the lecturer being crap didn't help much either.

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21st July 2006, 05:00 AM
dknguyen Experienced Member	The voltage difference between the two leads just happens to be the AC sinusoid. In reality, either lead could be whatever voltage you want relative to the surroundings/ground, as long as the voltage difference between the leads always makes a sinusoidal wave. The neutral just means that one of the leads just happens to be tied to the ground so that it doesn't float around too much. But it doesn't have to be for AC to work. IN the general case it is not necessary to have a "fixed constant" voltage reference in AC. It's just the difference between the two. You can think of it one of the wires (it doesn not matter which one,) as a reference that changes. Sometimes one is tied to ground which fixes the reference, but again, it's not necessary. Last edited by dknguyen : 21st July 2006 at 05:10 AM.

30th July 2006, 01:11 AM
dreadengineer New Member	I think we should be clear that in AC current, the electrons do actually turn around and flow back the other way. If it doesn't make sense that you can get power out of that, think of it like water in a pipe. If the water flows back and forth, you can still put a propeller in the water, and it will be turned alternately forward and backward, and you can get power from that. The source of the power comes from whoever is pushing the water forward and pulling it back, which is the power company. You can get power from AC current the same way. For example, an AC motor makes the electrons do work as they move forward and again as they move back. It's probably less confusing to just think of the voltage: the voltage between the two plugs on a power outlet alternates -- first a higher voltage on the right one, then a higher voltage on the left one, and you take that voltage and do something with it.

30th July 2006, 01:21 AM
dreadengineer New Member	Also, about voltage, like the post above was saying, voltage only has meaning as the RELATIVE voltage between two things. That's how we can say that one wire of the power outlet is neutral: it's held at the same voltage as the ground. So if you touched that wire and touched something that was grounded, like a water pipe, you shouldn't get shocked. But the other wire is going between +120V and -120V relative to ground. So if you touch it and the ground, you will get shocked, because there's a relative voltage. Whenever someone says something is at a voltage, like, "this wire is at 5V" it is implicitly relative to a reference. For example, in a portable device, it's relative to the - terminal of the battery. Saying that the wire is at 5V means it's 5V higher than the - terminal of the battery.

30th July 2006, 03:33 PM
Hero999 Experienced Member	The -v terminal of the battery is often considered to be the referance point 0V. Dual power supply circuits have the referance point taken between the two batteries. __________________ What's so bad about Microsoft? Get Opera it's simply a superb browser.

5th August 2006, 10:49 AM
gokulakannan New Member	hi i'm a Final year Electrical & Electronic Engineering student like to do a project in Embedded systems i need a sample projects for my reference

29th January 2007, 03:26 AM
mybuickskill6979 Experienced Member	so the amount of electrons that pass a given point in one second is an amp? and a coulomb? Sweet!! thats one word that confused me when reading about farads and capacitance!!

29th January 2007, 07:36 AM
ericgibbs Experienced Member	hi srimannarayanakarthik, Look at the thread 'electron velocity' download the *.zip posted by luisgerman. This should help you visualise electron 'movement' in a conductor. Regards EricG

29th January 2007, 04:29 PM
mybuickskill6979 Experienced Member	thats alot of electrons. Thanks Ron.

30th January 2007, 01:16 AM
Sceadwian Experienced Member	You should try calculating the amount of electron motion that occurs for a thousand watt space heater benig on for 8 hours. __________________ Curiosity killed the cat; That's why they have nine lives.

22nd March 2007, 10:20 PM
ikalogic Experienced Member	i like this analogy between hydraulis and electricity __________________ Ibrahim Kamal check my electronics and robotics page: http://www.ikalogic.com/ Last edited by ikalogic : 22nd March 2007 at 10:22 PM.

23rd March 2007, 01:38 PM
OutToLunch Experienced Member	i don't remember the specifics anymore, but in a system dynamics class in college, we took mechanical systems and translated them to an 'equivalent' electrical circuit and would use that to predict response. i remember having to do a project where the response of a car was found in relation to the tire hitting a bump in the road. The mass translates to inductance, Springs translate to capacitors and the shocks (dashpots) translate to resistors.

23rd March 2007, 01:51 PM
Hero999 Experienced Member	Sounds like LRC circuits and second order differential equations, I was never any good at that the lecturer being crap didn't help much either. __________________ What's so bad about Microsoft? Get Opera it's simply a superb browser.