1. hi.......
I knew that electrons in a direct current move in one direction but in an alternating current they move in in both opposite directions.....

i was wondering how this can happen , i mean how we can force electrons to move in both opposite directions ????
And why mechines like ACs use alternating current rather than direct current?

2.

3. Just a few points....

AC is much easier, and less costly, to trasmit over long distances using high voltage, low amerage, then converting to high amperage, low voltage at the home.

Electricity isn't necessarily the "flow of electrons in a direction," it's just electron flow. As long as they are moving, it really matters not which direction it's in....generally.

I think you're making a fairly common mistake when picturing what is happening. Electrons, when "flowing," are not all moving like say a waterfall. They're being passed along...one electron exiting an atom, entering another, then that atom releases an electron and passes it to the next..and so on.

Ever seen in the old days how they used to put out fires, before the fire engine was used? People stand in a line and pass buckets of water between each other. That's sort of how electricity works.

4. Originally Posted by CaveatLector
Just a few points....

AC is much easier, and less costly, to trasmit over long distances using high voltage, low amerage, then converting to high amperage, low voltage at the home.

Electricity isn't necessarily the "flow of electrons in a direction," it's just electron flow. As long as they are moving, it really matters not which direction it's in....generally.

I think you're making a fairly common mistake when picturing what is happening. Electrons, when "flowing," are not all moving like say a waterfall. They're being passed along...one electron exiting an atom, entering another, then that atom releases an electron and passes it to the next..and so on.

Ever seen in the old days how they used to put out fires, before the fire engine was used? People stand in a line and pass buckets of water between each other. That's sort of how electricity works.
...just picture that what mattters is not that water reaches and end, but just that it is moved in whatever direction, if even back and forth of the same two guys... "voltage" would be the comamnd voice saying "back" or "forth" (techincally, it is a electromagnetic wave with a freequency of 60 Hz in the USA and 50 Hz in most of Europe. This means that alternate current generators in the USA send down the power line a electromagnetic wave with a wavelength of some 5,000 kilometers... and this waves are pretty real, as you may notice if you ever put a fluorescent tube under a high tension line... the waves from the power wires will ionize the gas within the tube and they will shine without a power supply. It's pretty cool)

5. but just that it is moved in whatever direction, if even back and forth of the same two guys.
Of course, that's why I mentioned:
Electricity isn't necessarily the "flow of electrons in a direction," it's just electron flow
The analogy is just to give almirza an idea of what's happening.
Good point though.

6. Originally Posted by almirza
hi.......
I knew that electrons in a direct current move in one direction but in an alternating current they move in in both opposite directions.....

i was wondering how this can happen , i mean how we can force electrons to move in both opposite directions ????
And why mechines like ACs use alternating current rather than direct current?

Putting it in another way:

-> DC: is electrical current flowing in one constant direction.

-> AC: is electrical current flowing in one direction first and in the oposite direction then, both directions alternating with a certain frequency (not at the same time).

...where electrical current is understood as the displacement of electrical charges (electrons) in time.

7. Thank you friends

But i think this talking became out of my scoop

8. dont confuse him lol, lisen ac curent is caled acelerated cause it change, u asked why and how here how, when u have battery it have + and - end well imagine u have allso another battery that have + and - end what hapen if u connect - end of one and + end of other this batteryies +|===|- +|===|- well for bouth of this batteries conected complete voltage vill be 2 times of one batteries. but what if u use center junction as one referent point. on left side ur voltage will be if u mesure it up on volt metter +1V and on other side it vill be -1V, WHY, if u keep same connection of voltmeter j2 on +- junction and u swich j1 connection from + of left baterie to - on right one it inversed connected, in reality is just referent point. well that how u get minus voltage, this simular happen on ac curent but curent drop constantly during time and rise constantly during time, imagine it like +- junction is 1 side and other side is constantly fast swiched betwine + and - on bateries end that how electron change way of going.

+|===|-+|===|-
| |
| |
[--(V)---]
j1 j2

next question is why if prefered uses of ac than dc current, well my countrimen nikola tesla that went for america saided that wery clearly,
Losses in conductors ar definitly done by current not with diference of potencial (VOLTAGE), that why u have power cables that run up to 220000 Volts, but in other to decrease that high Voltage to usable one u must have some way, that is why is AC not DC cause transformation of AC curent from high to low is done by TRANSFORMATORS and theory of magnetics say if u have constant magnetic feald there no inducated curent on other side of secundar explanation transformator is made of primar and secundar on primar u get one voltage on secundar u get other it depend on numbers of winding but in general if u connect direct curent on primar it wont make power on secundar cause magnetic field that primar make is not alterated, is CONSTANT cause dc power but if u connect AC power on primar it will make AC power on scundar that how u get 220000V to 110V AS or 220V ES in general use of ac is alot more better regarding losses, and it much more usable than DC like sinhron motors, aplification of power ect...

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