What is the differences between alternating current (AC) and direct current (DC).

For a thorough answer, click on the following link:

http://science.howstuffworks.com/electricity8.htm

Well Shak, in short (pun unintentional), in dc the flow of current (usually electrons but not always) is continuous from source (battery, eg, outside, negative or bottom terminal) to the load (eg, bulb) then back to the source (in this case center or positive terminal), usu at constant magnitude. But why is electron "suction" referred to as "positive"

Because early on it was thought that current flows the other way. Still some defend the terminology inasmuch as positrons etc in fact do

…while in ac, direction of flow reverses usually at regular interval (eg, generator), often its magnitude graphed as sinusoidal

Without revealing anything critical to your identity except Sharing the Impact of the Car, please tell us something about yourself, eg, age, sex, nat'l, ed., motives, fam, etc

I envision a young man of other than Engish-speaking world lying in hospital bed recovering from wounds of a collision while attempting nevertheless to persevere in his homework

Why do you feel the need to make stuff up on topics you know very little about.

Positrons flow the other way... really? You clearly are clueless on the subject.

Indeed Max I'm kind of clueless about antimatter and the like. I guess however they'd flow that way in an antimatter universe

http://forums.xkcd.com/viewtopic.php?f=18&t=12395

In my own defense though, maybe around the magnetar

http://arxiv.org/abs/1209.4063

But how about positive ions in an electrolyte

http://www.physicsforums.com/showthread.php?t=347893

Tho yea Max, I should stick with electrons
And, oh, Shak, apparently they don't flow so much as drift

Dale, I see maxdancona didn't feel inclined (or able?) to offer any on-topic help.

Maybe Con we will still hear from him

I did offer on-topic help.

On an academic question such as this, it is a bad thing when someone who doesn't know what he is talking about to pretend to have expertise. Someone making an honest inquiry can be misled or frustrated.

Letting the questioner know that he or she can trust Ragman, but that Dale is clueless is helpful. Someone who doesn't know the difference between a positron and a positive ion shouldn't be faking expertise about either.

Someone pretending to have expertise in an area he knows little about is harmful. If Dale were simply enquiring about the topic, or participating in a discussion, I wouldn't be upset. I am upset because Dale is pretending to have a level of expertise that he or she clearly doesn't have.

It is helpful to know who is pretending.

My golly but I must be a terrible person

My most abject apologies to all

You can see now, Dale, why I said your advice can be dangerous.

Maybe you could talk about painting daffodils in Greenland and leave electricity and electronics to those who know about it..

Actually Tim I flunked out of Engineering School, accounting for my unfamiliarity with the habits of the positive charge--tho I've spent the greater part of a lifetime in electronics, writing instruction books and inventing about a dozen gadgets of one kind or another, some actually electronic

Know even less about the daffodil

Am I supposed to be impressed by your credentials?

Given the emptiness of your discourse, I wonder what Engineering School you attended..

It's unnecessary

Flunked the vast emptiness of a certain Midwest university

But Shak, has any of us been of the slightest help whatever

I have to say, that out of maxdancona and dahileman, I actually like Dale more. He doesn't post like a prick, and seems like a regular kind of guy.

Thank you Con but I often regret baiting 'em, it's not the greatest way to relate. Instead one ought to set a better example

Alliteration unintended

I am OK with that Contrex.

I think that people who come here for academic help should be be able to get real help, from people who know what they are talking about, without being misled. If that makes me a prick, then so be it.

I have a particular disdain for bad science.

Power streams in two routes: either in an exchanging current (AC) or in an immediate current (DC). Power or "current" is only the development of electrons through a channel, similar to a wire. The contrast in the middle of AC and DC lies in the bearing in which the electrons stream. In DC, the electrons stream consistently in a solitary course, or "forward." In AC, electrons continue exchanging headings, once in a while going "forward" and after that going "in reverse."

Exchanging current is the most ideal approach to transmit power over expansive separations.

DC Transmission:
Some times ago. The Electric power transmission was in DC due to the following advantages.
Advantages of DC Transmission
Advantages:
There are two conductors used in DC transmission while three conductors required in AC transmission.
There are no Inductance and Surges (High Voltage waves for very short time) in DC transmission.
Due to absence of inductance, there are very low voltage drop in DC transmission lines comparing with AC (if both Load and sending end voltage is same)
There is no concept of Skin effect in DC transmission. Therefore, small cross sectional area conductor required.
A DC System has a less potential stress over AC system for same Voltage level. Therefore, a DC line requires less insulation.
In DC System, There is no interference with communication system.
In DC Line, Corona losses are very low.
In High Voltage DC Transmission lines, there are no Dielectric losses.
In DC Transmission system, there are no difficulties in synchronizing and stability problems.
DC system is more efficient than AC, therefore, the rate of price of Towers, Poles, Insulators, and conductor are low so the system is economical.
In DC System, the speed control range is greater than AC System.
There is low insulation required in DC system (about 70%).
The price of DC cables is low (Due to Low insulation)
In DC Supply System, the Sheath losses in underground cables are low.
DC system is suitable for High Power Transmission based on High Current transmission.
In DC System, The Value of charging current is quite low, there fore, the length DC Transmission lines is greater than AC lines.
Disadvantages of DC Transmission:

Disadvantages:
Due to commutation problem, Electric power can’t be produce at High (DC) Voltage.
For High Voltage transmission, we can not step the level of DC Voltage (As Transformer can not work on DC)
There is a limit of DC Switches and Circuit breakers (and costly too)
Motor generator set is used for step down the level of DC voltage and the efficiency of Motor-generator set is low than transformer.
so the system makes complex and costly.
The level of DC Voltage can not be change easily. So we can not get desire voltage for Electrical and electronics appliances (such as 5 Volts, 9 Volts 15 Volts, 20 and 22 Volts etc) directly from Transmission system.
AC Transmission:
Nowadays, the generation, transmission and distribution mostly is in AC.
Advantages of AC Transmission System
Advantages:
AC Circuit breakers is cheap than DC Circuit breakers.
The repairing and maintenance of AC sub station is easy and inexpensive than DC Substation.
The Level of AC voltage may be increased or decreased step up and Step down transformers.
Disadvantages of AC System
Disadvantages:
In AC line, the size of conductor is grater than DC Line.
The Cost of AC Transmission lines are greater than DC Transmission lines.
Due to Skin effect, the losses in AC system are more.
In AC Lines, there is Capacitance, so continuously power loss when no load on lines or Line is open.
Other line losses are due to inductance.
More insulation required in AC System
Also corona Losses occur In AC System,
There is telecommunication interference in AC System.
There are stability and synchronizing problems in AC System.
DC System is more efficient than AC System.
There are also re-active power controlling problems in AC System.