Circuits (part 3)

[ScottieHProductions]

Thank you so much! I think I can pass physics now! :D

[fantasticmrbongo]

pls tell me how to make a circuit where switch one has to be on for switch 2 to work

[pperezvillacastin]

Thanks a lot for this, I was struggling with the concept of potential and the way capacitors/resistance affected it.

Its all soo clear now

[abidrosesmell]

is the fan resister

[dee123deeful]

I love you

[beer94]

what if he starts smoking pot and turns into kumar?

[ryanmerkle5]

When I graduate I am going to donate atleast $1000 to you.

[yogeshdelhi1]

sal alwys says " i dont know ",,,but in reality he knows everything whats going on

[NbulianJohn]

why does each of the devices in a parallel circuit get the same voltage even though the resistances are different . pls explain

[kourosh89]

@NbulianJohn I have the same question but my guess is that the parallel circuit can be thought of as two circuits and the voltage drop is the same in a battery as long as one of the points is not in between two resistors.

[joaquin174]

MAGENTA!



[akhsnow]

screw the like button, where is the love button :)

[NewgroundsOwnSBB]

you call them printer burps? that's so adorable!!

[Alka30001]

1 person's brain is as big as the dislike bar.

[senten123]

wow thank you so much

[findvoltage]

i realy blew a fuse when you changed to magenta.

[maathemeatloaf]

new colour will be MAGENTA

[Ommu1995]

dude...... I love you man.... why cant YOU be my teacher lol???? BEST TEACHER ON YOUTUBE HANDS DOWN!

[JRockey0915]

@Ommu1995 Freelanceteach has him beat.

[honorhonorhonorhonor]

I call them printer burps.

[apparentlyokay]

you're a genius but i can't help adding the fact that you REALLY can't draw a straight line hahaha!

[FLAMERNECRO]

THANK YOU !, never understood how v/r + v/r is 1/r + 1/r, AWESOME!

[spilloholiker]

Zero dislikes!

[mrbarnabywells]

@spilloholiker tempted to dislike now?

[spilloholiker]

@mrbarnabywells I'm not that much of a douchebad ;)

[kittykatblabla]

Nice videos! they are very helpful. Do you have any videos on complex circuits?

[gobbledygookie]

What is it with Sal and megenta? *chuckles*

[Sellennaaa]

I can't believe this is free.

[lazer1235]

@Sellennaaa don't give him ideas! :P

[gbmack2000]

water pipes, you mean bongs?

[JonProce]

"I call them printer burps"

[tadm123]

you are the reason im becoming a professional, thanks a lot

[123conundrum]

You are a genius!

[richimf]

this also help me itunes.apple.com/us/app/star2d­elta/id417605678?mt=8

[viptutorialscom]

The cool thing is that adding resistors in series DECREASES total resistance of the circuit and INCREASES current flow. Why? Think about having a gate through which everyone (all electrons) must pass (ie. toll-gate). If you add another gate PARALLEL to it (meaning now instead of just 1 e- passing, 2e- can pass at the same time). Since current is defined as Q/t, we are allowing 2x charge to flow in the same amount of time, hence current increases :)

[alifawad1994]

@viptutorialscom Nicely said.

[mrbarnabywells]

@viptutorialscom do you mean in a parallel circuit not a series circuit? :P

[ATMfromNJ]

Great job Professor! You rock!

[Harref2007]

Its relly great,, Thanks

[chefnaj]

thank you very much sir

[syedwaqasali95]

please come to pakistan and start teaching we are dying of shortage of good teachers

[hendsem]

Please come to NTU and be our lecturer - we cant understand a single shit our china lecturers are spittin. love from singapore.

[TheUnchainedBeast]

wat excatly r coloumbs?

[yo3443]

@TheUnchainedBeast i think it's charge

[viptutorialscom]

@TheUnchainedBeast It is a measure of charge. So if you want to understand it better here it is: 1C=6.24x10^18e Meaning that in order to describe amount of charge moving, Coloumb came up with this convention. One electron has a charge of -e. You can just imagine how HUGE 1C must be. Think about a bucket that holds 10^18 electrons in it. That is a VERY LARGE amount of charge.

[TheUnchainedBeast]

@viptutorialscom Oh thanks i get it

[markkevnjflores]

printerburps! hahaha

[yazicib1]

Many thanks Salman.... I am a veteran software engineer trying to re-learn electronics for my robotics hobby and your courses are helping a lot to refresh my memory... You are doing awesome teaching job, please keep up the excellent work, and don't let your popularity stray you into politics or some other evil thing :)

Peace!

Baris

[supermanXL]

great teaching

[11par]

printer burps lol

[mexman48]

The electrons do flow from positive to negative !!!!!!!! What makes you say that electrons flow from negative to positive? Do you have proof of that?

[rachi6]

@mexman48 of course! the electrons are negatively charged, it's natural they thus flow from -ve to +ve

[hurumi]

@mexman48

He is just telling us what the convention is, even though the charges of electrons flowing, is actually out from the negative terminal. You can maybe think of it as:

negative charges move to higher electrical potential

positive charges move to lower electrical potential

and the positive plate has higher potential so electrons move twds there. if it had been a positive charge it'll go to -ve terminal (lower potential).

[soulpowerpaul]

@mexman48 the electrons will be attracted to the opposite charge (positive charge), so they will move from the negative to the positive

[yazicib1]

@mexman48

Negative charge means, there are more electrons on that side of the circuit by definition as the electrons themselves are negative charged particles. So they are simply trying to move from the point they exist a lot to they exist less. This is a spontaneous process possibly due to entropy and has to obey the laws of thermodynamics. Just like a rock falls to the ground but doesn't spontaneously fly.Flying means increasing potential energy and that is not possible in a closed system.

[dalcde]

I totally agree that charge flows from negative to positive. What I don't understand is that why are fuses in electrical appliances put at the positive side, after the appliance?

[yazicib1]

@dalcde

Appliances are AC devices usually. The fuse is put on non-ground side of the appliance. Ground is basically a wire connected to the earth (largest sphere we can think of) The other wire (non-ground I guess, I am not sure what it is actually called) is the actual wire that carries alternative current. Flow of electrons in AC is constantly changing in a sinusodial wave from one direction to other. And this is 60Hz in US, and 50Hz in Europe, etc.

I am sure Salman has another video on AC

[SiegeCoD4]

why the hell cant my teacher just shut her trap and play these videos all class.

[commanderkool868]

Thank you so much Sal. I'm in a youth program at a college and we have a quiz on this circuit stuff tomorrow, but I haven't taken physics yet and I felt so lost. After watching these first three videos I feel like I am beyond prepared for the quiz. Thank you again

[Leonimy]

thankyou dude. So helpful!!

[Amato1Allah]

Thanks A LOT!!!

[megamusic49]

This helped me in science! Thanks Sal.

[Primerythm]

lol printer burps

[SteveKarlEdelen]

it's all too messy to understand.  I tried.

[rinwhr]

7:54, I don't get it, why does he say that it slows down at the resistor point, but then he says it must be not be slower than the other points?

[yazicib1]

@rinwhr Due to conservation laws (Kirchoff's law), the current flows in a series circuit has to be the same in all points of the circuit. Since current is basically rate of change of charge per time, it is basically the speed of electron flow. So by this definition if there is a resistor in a circuit, all electrons that are coming into it and out of it will have to slow down so that kirchoff law holds. This is only possible if there is a voltage drop across the resistor. And this is the case.

[minsatminsat]

why do u not put +ve n -ve signs for ur resistances? i don't know how to choose the app sign for my resistances

[minsatminsat]

sorry! i meant ammeter and voltmeter. why don't you put the polarity signs for ammeter and voltmeter?

[shadeofgrayx]

yay magenta

[Thymonico]

Tjihihihihi... "Printer burps"... Tjihihi! Best part of the video! The other stuff was cool too!

[bkisme]

Hah, and now I remember the Modest Mouse song "Path of Lease Resistance" and now I know, despite (not) learning this in my physics class for weeks, that this principle is true, as electrons prefer to flow where there is least resistance, causing the 5 ohm resistor to carry more electrons so to speak as the 20 ohm resistor.

Thank you. :)

[bkisme]

heh, i remember in my silly physics class running many resistors in parallel. I remember how confused I got when the voltage would eventually get really close to the voltage of the battery, and now it makes a bit more sense :p

[PeaceLoveFairytales]

thanks for making physics intersting...

[PeaceLoveFairytales]

omg you're so funny...

ahahahahhaa....

LOL.

[FerretDude41]

you are a good person

[sherajr]

hahaha, printer burps :)

[StiegeNZ]

Heya,

I think a good word to describe the flow of current in the conventional direction is to express it as electrons jumping through free spaces between atoms, and conventional current as being the flow of 'holes' or 'gaps'.

Thanks heaps for your work, you're going to get me through an Electrical Engineering Degree over the next 4 years.

[speckhard2]

i love you

[lllakiralllsanlll]

thanks man!

[Penksimo]

i am so confuse at 9:49........why 1/R or 1 over everything ? and why 1/5 became 1+4 over 20?

[croxbreed]

1/20 + 1/5 became 1/20 + 4/20 or (1+4)/20.

if you really can't wrap your mind around that, here's another trick to calculate the equivalent resistance of two parallel resistors: Re = (R1*R2) / (R1+R2)

[woodenjaw]

I have something like that in my test book, but the shape is in triangles.

[lionessgurl]

u r the best, wish you were my teacher, thanks a lot man

[kirill124]

i guess just stick to one meathod of thinking how this shit works or just keep the belief of how it works since we cant actually see atoms.

[Whiskeydrummer]

Great. just when I think I got it, now I am thinking of beetle bailey (7:48) . Great....

[vickiormindyb]

These videos have been really helpful in understanding Electrocardiography. When I was an EKG Technician, I had the hardest time understanding and gave up trying to, but this is proving very helpful.

Imagine what it's going to be like when I study the heart's Conduction System; a lot easier than before.

[polos505]

hello Sal. I was wondering if the voltage is the same at different points of a circuit. if it is different, how do you calculate it? great video!

[brentwoodbc]

right when Im about to go "wait what about...." he answer my question haha awesome thanks.

[ahmedshah1990]

U r the best guy on youtube!

[immortal6699]

IN THE WORLD

[azm1987]

you are great thank you

[iamanubertuber]

I know this is really off topic, but you always speak of "intuition" in your videos, which is a topic i am interested about. I'd be very interested in knowing what your understanding of intuition is and its relation to other forms of understanding. I'm going to go ahead and request a video about it too.

[68951232]

i did not understand how he solved it...

[mahivell]

ohmygod, im having my physics exam tomorrow. and this video really cleared my doubts and frustrations. rock on dude :D

[Judi214]

Teach me on how to solve parallel circuits... I'm not good at physics ^^

[htmlfreak]

thanks for the vid!

[gerardosilva1980]

Hi Sir, great serie of circuit videos. Keep it up!

[spaff61]

thank you for posting this

[dukeisaac]

hi sir can i ask a question???

i was so confuse about what is the flow of electrons..

is it from negative to positive ? or positive to negative?

[spaff61]

they are from negative to positive but they are marked on as going the other way

[darkwspyder]

LOL! You never cease to make me laugh! Thanks for the videos! You should definitely become my physics teacher! lol :)

[tiptopmini]

Thank you so much for these videos! They have helped me a lot in preparing for my tests and have saved me from failing my physics course.. Thank you! :D