Direct Current versus Alternating Current

[combzcombz]

@szederp Haha funny how much it upsets you bud.

[rasputozen]

Quick question... how would AC current make it all the way around a circuit that is very long (let's say a million miles) if it continually goes forward and back?

Thanks in advance!!

[rasputozen]

Wow, finally what I was looking for to understand AC as compared to DC... Thank you sir!!!!!!!!!

[anfobomb]

qiuck question! how to i make 12dc to 12AC (around 50hz)??

[Sebeerful]

@SParenotEMO see on the AC the circle with the squiggle line in it the top is positive and the bottom is negative the sine wave alternates between positive and negative

[MrAbbeyisa]

Thank you for this information.

[Idkfawin32]

you know, in my 21 years of being alive, nobody has explained AC and DC currents as well as your video has.

[SParenotEMO]

So there is no + or - in AC or does it just not matter?

[singasozhan]

thank you

[djk4tt]

18 ppl who watched this video are fans of Edison :X

[90zlaya]

Thanks to Mr. Tesla, we now have better electricity and can run powerful machines.

AC (alternate current) changes pole two times in one period, while DC (direct current) is constant. You cannot transform DC like you can do with AC. World with DC would have power station on every mile. Electricity would be much expensive with those system.

[randyfletcher86]

well that was helpfull

[VirtuaNick]

soo...wuts the difference???

[Numbersixteen16]

So if an AC current was hooked up to an electromagnet, would it keep switching the magnet from positive to neg? And could you controll the time the magnet spent being positive or negative? Otherwise, is there a way to make an electromagnet change from positive to negative? Thanks.

[geniepwn815]

Fake and Gay

[dyrdekrulz]

lol ACDC even though i dont listen to them :3

[VEGETADTX]

This 10 seconds long animation explained me more than most of unnecessarily complicated talk by many many people so far.

Good old saying - single picture shows more than 1000 words.

That's why I never liked books! its just another shallow complex and trend forced onto kids out of that "no high school degree - no life!" philosophy...its not the BOOKS that are great, helpful and educative, its WHATS WRITTEN IN THEM, so let us all grasp the knowledge the way we choose and the way it suits to us.

[Ottoman828]

i still wouldnt stand in a puddle and touch the neutral...

[combzcombz]

i was going to use this animation for my class, until i realized you showed the electron movement going from positive to negative. fail

[mrg3]

@combzcombz I use conventional current flow as the visual element for all my animations involving electric current. In my 20+ years of teaching, I have found that harping on the actual motion of the negative charge carriers (which has absolutely NO significance in circuit analysis) leads to MORE confusion. Franklin's ill fated 50/50 choice on sign conventions for electric charge has led to many a student heartache. Perhaps you could clue your students in to some historical perspective.

[wbeaty]

@mrg3 Just replace the wires with salt water hoses. No electrons flow in water, only Na+ and Cl- ions are flowing. And they go in opposite directions. What's their real direction of current? Or add a piece of proton conductor to your metal circuit. Proton conductor is the plastic used in fuel cells.

In other words, if you know the direction of current, the direction of charges depends on the type of conductor. If it's unknown, it's "conventional" current of signless (positive) charges.

[dressedtosmellgood]

@mrg3 alternatively, read the tao te ching for a different perspective

[salimkhan007]

@combzcombz can you show how DC and AC really work in circuit .on animations

[wow1022]

@combzcombz

current always flows from positive to negative >_>

[SuperKmach]

@combzcombz current is different to the flow of electrons. moron.

[jasarite]

@SuperKmach Current would be measured in watts or amps is a measurement of electron flow

[jishan22]

@combzcombz Just reverse the video using Windows Movie Maker or any other video editing program.

[Szederp]

@combzcombz Haven't heard of conventional current flow? Wow, how hard you fail, it is really pathetic. Why is it that it is always morons like you try to lecture others? Don't answer!

[chehar]

AC has a positive and a negative half cycle, it is reffered to as a sinusoidal wave (sine wave) it completes one full cycle 0f 360 degrees half of that being 180 positive and 180 negative. when AC is modified into DC rectifiers are used, such as half wave and full wave, using simple diodes to convert.

[deezynar]

I have a book on residential electrical wiring by Home Depot. It has some pictures of a couple circuits w/ arrows on the white & black wires that indicate the current flows out on the black wire & returns on the white wire. I have seen this same idea presented in other books as well & I've spoken to a handful of electricians who believe that is how it actually works. There is a real lack of teaching resources that show how it actually works - out & back on BOTH wires.

[MBC022]

so those plugs that can only be plugged one way are for DC devices

and the ones that can be plugged either way are AC?

and whats that third hole for? ground?? which i think DC devices wouldn't need cause the negative pole would be the ground

[mrg3]

@MBC022 Polarized two prong plugs are for AC and have one side tied to the ac voltage and the other side tied to electrical ground. For safety, you have the chassis inside the device tied to the ground side. If the plug is plugged in backwards or the outlet is wired backwards, you get the chassis wired "hot", which presents a hazard if the device case is opened. I believe the three prong plugs are an older version, with the third round prong being the ground.

[BaltoMovie]

still confused about AC

if the electrons are moving backwards how is the machine getting power?

[Ottoman828]

@BaltoMovie ok so in lamens terms the electricity is giving and receiving volts and current, pushing electrons back and forth ... like those 5 balls in some peoples offices where only two are moving back and forth but the three in the middle absorb and send the shock wave. Now those electrons are moving at such high speeds that ud never be able to see the flickering in lights or stoping and starting of ur vaccuum, dryer, etc...

better???

[mahadebchanda82]

how can i calculate amperes

[BIGTROUT01]

@mahadebchanda82 Amperes=Volts/Ohms or Amperes=Watts/Volts or

Amperes= the square root of Watts/Ohms.

This is a manipulation of Ohm's Law.

If you have two of the values, you can calculate the other.

Find an Ohm's Law pie chart and it will show the relationship between Amperes, Volts, Watts, and Ohms.

[1emu3e]

dc has frequeny =0 and

ac has frequency differ from 0

[Stanislavs1]

so thats why you can mix up + or - in an AC system, and it will still work? how about DC, will it still work if you mix up + and -?

[mrg3]

@Stanislavs1 AC you can mix switch sides, with DC it will depend upon the application. A light bulb will work with DC in either polarity but a motor might run backwards.

[jonbar87]

@mrg3 unless you have a bridge rectifier installed in the circuit. then polarity does not matter, it'll still run the right way because of how the diodes are setup

[deezynar]

@Stanislavs1

The current flows back & forth in both wires but the wires are not equal in function. The neutral wire is connected to the neutral bus bar in the panel & that's connected to the ground bus which is wired to the earth. That means you can't be electrocuted if you stand in a puddle & touch the neutral wire. However, you'll die if you touch the "hot" wire. I've never seen it happen, but I've heard that some electronic appliances get messed up if they're plugged in the wrong way.

[Serostern]

@Stanislavs1 Yes, AC doesnt care wich way it runs.

That is confusing to americans, since your plugs can not be put in upside down, but not confusing to germans, since their plugs can be turned upside down without any difference.

But if you mix up the + and - (poles) on a DC motor it will turn the other way =P

[Sonicku]

i dont get it i thought electricity can only go oneway? that it coulnt stop and reverse direction.. wont that turn off the machine?

[mrg3]

@Sonicku

It depends upon the machine. A machine/motor designed for AC won't work on DC and a machine/motor designed for DC won't work on AC. A lightbulb won;t really care either way.

[livofc1]

@Sonicku

Just expanding on what mrg3 said.....it doesn't make a difference because in an AC current, the current flows back and forth really fast. For example in the US, the AC current supply goes back and forth 60 times a second, meaning that in a light globe, the human eye cant register this "on an off" sequence fast enough and so it looks like a continuosly shining light to us. For machines on the other hand, as mrg3 said, they are designed to work sepecifically for AC or DC.

[icelez]

@livofc1 so that's the flicker in old tvs and computer monitors

[mrpotatfacemn8675309]

and the name AC/DC came from Angus and

Malcom's younger sister, Margaret

she gave the band their name off of a sewing

machine

[vrhitman]

Excellent illustration!

[rollingroses]

how does the AC current reach destination if it keeps coming back and forth ?

[sypha0x]

nature operates in AC. So it's easy to transport AC to long transmission distances via the wire due to it's ability to handle high voltage and low current phases. DC however suffers in this respect. AC is the natural way of dealing with power.

[TibbyMy]

@sypha0x But nowadays the applications for transmitting to high distances over 100km or more are focusing on high voltage DC transmission because it has less losses on the line.

[zelunika]

ac has have half positive and half negative in order to convert it into dc we convert it into positive cycles only.right......long time ago ppl were using dc currents but it waz not only dangerous but having large power lossses.

[Fruitjoke]

I get the flow of electrons thing, but how do you make ac or dc? what must you do, to force the electricity to be ac or dc??

[marneedear]

You simply need an AC power source -- an alternator.

[ikedasquid]

Generally, AC comes from things that spin or reciprocate (like generators or alternators, those flashlights that you shake etc) and DC comes from everything else (batteries, solar panels, thermocouples, etc). Diodes can be used to convert AC into DC but going DC into AC is more difficult. You can use an inverter or a motor-generator pair (anyway it usually involves a whole machine, whereas a diode is just a small component).

[Rickertat]

hey dude u know where the band AC/DC comes from? THIS! thats why theres a bolt in the middle and there first song album was name HIGH VOLTAGE! ACDC ROCK EELLECTRIICCC

[Hb35Jazz]

Isn't electrons movin from the minus to the plus on the battery?

[mrg3]

Yes, you are correct.

I am just trying to provide a visual aid for the flow of "conventional current", but at the microscopic level, electrons are actually moving in the opposite direction.

[Hb35Jazz]

Ok, thanks :)

 - I just had to be sure ;P

[chemy999]

@Hb35Jazz nope, technically they should but our batteries are mislabeled. or so many a textbook and online source have said.

[CJackSparrow79]

nice

[Ingridtk]

thanks.