Physical Science 6.5a - Series and Parallel Circuits

[milescyrus13]

Aww thank you so much for the help! Good teacher!

[rojocapo610]

Fist thanks for the video :) now onto the question if you have some time.

1) on 7:30 you said that if in series one of the bulbs burned out the other 2 will not work. So If the second of 3 bulbs were out wouldn't the second and third not work but the first one will since the current is still reaching that first bulb ? I mean from the broken resistance to anything after it not work but anything before it would?

2) So basically in series is the wrong way to do things?

[rojocapo610]

@rojocapo610 nvm i figured in 1) that if the current does not make the full loop then it would make not work.

[Faesalmajid]

i have a question about parellel , when a lightbulb burns , woudnt that give more power to the 2 others which will eventually leads to the others to burn ?

[derekowens]

@Faesalmajid Actually, it would not. If three bulbs were in parallel and one burned out, then the total current drawn from the battery would decrease. The power in the other two bulbs would basically stay the same.

[JavaLuCpp]

I live how this guys did this on a real tablet back in 2009. Only a year after where the iTablets comes out. Ahh, the good old day of MS tablets where you can actually do real things on.

[VastQQu]

Great! really helped me in standard grade physics :)

[8644371]

Can a lightbulb be a resistor?

[derekowens]

@8644371 Yes. A typical incandescent bulb glows because the electrical resistance creates heat, and it gets hot enough to glow. You could diagram a circuit and do all the math as if it were a resistor, and the current and voltage calculations would be the same either way.

[sadiq119asma]

thanks man if i didnt see this n didnt understand it my tutor was gonna kill me.. wooo!!! 5 star*****

[metaltera86]

This video def helped me for electronics class

[zeledonheri]

great job dude for real. super helpful

[reLIEablity]

this video is so good. my science teacher isn't the best at teaching this topic so i didn't understand this at all but as soon as i saw this, it all made sense! thankyou so much

[NeatMagic]

Thank you for this video it really helped me.

[balochan1]

I want moreeeeeeeeeeee, please upload more of ur videos. Much much better than khanacadmy! Now I love Physics and Maths......

[thevans8903]

Good video, and you know what your talking about. But i noticed that when you make your arrows showing current flow you do it from the positive side of the battery, and anyone who knows anything about this sort of thing should know that electrons discharge from the negative side of the battery....correct me if I am wrong anyone.

[derekowens]

@thevans8903 You are correct. Electrons flow from the negative terminal of the battery. If you are thinking about conventional current, though, you imagine positive charges flowing from the positive terminal of the battery. Either way is actually okay. Negative charges flowing one way is mathematically equivalent to positive charges flowing the other way.

[deesharkz]

very well explained video. Thanks!

[Forlorade]

Your illustrating was so clear and concise and neat. I love it.

Great video.

[SpeakSoftlyCharisma]

thank you so much for your videos they are great im taking an electrcian course in college and your videos just make me understand more with the detail you go through.

[BIKERMETOO]

Excellent ..very clear...well presented !!!

[ImUrtastyflava]

What happens to the power in the parallel circuit? If I had a 12Volt DC power source with 0.7 Amps of current and 8Watts of power in a parallel circuit?

I had 10 lanes in the parallel circuit it gives out 8Watts for each? And the power source gives a constant power.

[derekowens]

@ImUrtastyflava Yes, assuming that the power source is capable of delivering all of that power at one time, then each "lane" of the parallel circuit gets additional power. A small battery, though, might not be capable of delivering sufficient power.

[ImUrtastyflava]

@derekowens

Im making a turbine :).

it gives me good enough power! :D

[ImUrtastyflava]

@derekowens

It's not a battery I think it can power the lanes for just a few moments then spark out. But for example a generator can support that power.

Now I know if I had enough power I can go BEYOND in circuiting wiring and such I think parallel circuits are the best way.

Thanks anyway!

[sirsmokesdankalot]

love this plz dont remove useing as a study guid for my avionics  class ame with all ur videos

[frank0067]

Glad to see you convey the correct teaching of the flow of current being from the positive toward the negitive.. theres been some today who teach the power comes from the negitive.. erroneously, even on professional levels, but they are relying on flawed ideals there.

[derekowens]

@frank0067 Thanks! The distinction between conventional current and electron flow has been a source of endless confusion to students at all levels of instruction.

[SilyBily32]

@derekowens Ah, I see. The direction of the current flow is given with respect to a positive charge rather than a negative one (i.e. electron). Similar to the determination of the direction of magnetic fields. Wish my high school physics teacher didn't try to oversimplify these concepts.

Is it safe to assume that the direction of things like electric flow, fields, etc will generally be given with respect to positive charge?

[derekowens]

@SilyBily32 Yes, the flow of positive charge (which is rarely actually the case) is the way circuits are typically understood, by convention. This is therefore called "conventional current". In reality, it is electrons flowing. However, negative charge flowing one way is mathematically equivalent to positive charge flowing the opposite way, so it works out mathematically either way, but causes endless confusion to students.

[deville1017]

@frank0067 it doesnt really matter if the current flows from positive to negative or negative to positive

[frank0067]

@deville1017 WHy wouldnt it matter? i dont get ya

[deville1017]

@frank0067 cuz its a circuit its just going to go in a circle.....besides if u think about it....opposites attract and likes repel...and if electrons are the particles that flow through a circuit it would only make sense that electrons leave the negative terminal only to flow to the opposite (positive) terminal

[frank0067]

@deville1017 well you cant just think power comes from either pole.,it doesn't it comes from the transference of electrons that are in surplus toward the lack. thats why 2 different metals are used,to achieve this. if you use 2 similar metals inside the battery you cant have a surplus vrs lack transition of electrons.. they both would equal out being neutral. now the negitive pole doesn't mean lack of electrons .. rather only WITHIN the cell the electrons begin their journey to the positive

[frank0067]

@deville1017 ... so its only outside the battery that we assume the power or electrons reside from the positive in which it had collected from the negitive from inside the cell .

[osamamoto]

In parallel the current devides?

[derekowens]

@osamamoto Yes, in parallel the current divides and the voltages are the same. In series the voltage divides and the currents are the same.

[osamamoto]

okay thank you.

[derekowens]

@osamamoto It depends on the voltage of the LED's. They are designed to work at a certain voltage, and you need to make sure your circuit provides that voltage.

[osamamoto]

ok i understood.

[petitemasochist]

Thanks for describing this in such vivid detail! It's all making sense.

[protocolxero]

Waitt so how does the brightness of one bulb in series compare to the brightness of each bulb (when two bulbs are) connected in parallel?

[derekowens]

@protocolxero If you connect two bulbs in parallel, each one should be just as bright as a single bulb connected by itself, assuming that the battery is capable of producing that much current at one time, which is typically the case with small flashlight bulbs and regular batteries. Connecting more bulbs in parallel results in multiple bulbs burning brightly, and correspondingly more current being drawn from the battery.

[protocolxero]

@derekowens thanksss! it all makes sense now.

[ajet6]

Thanks a lot!!! Just subscribed! :)

[GreatestHooligan]

In a series, let's assume light bulb sockets are connected, We know that for each terminals on those socket, there is a brass on one end and there is silver terminal on the other end.

How do you position those sides when connecting them in series? Does it matter?

[delgadogorn]

can someone tell me what program is being used in the video where you draw like that?

[HUSTLEBANE]

why are series circuits still used than?

[thepieface9496]

you know you said the bulbs would burn just as bright in the parallel curcuit with more bulbs.....

would that mean the ammeter reading on the other side will stay the same however many bulbs you added?

[derekowens]

@thepieface9496 An ammeter that the measured the current through one bulb would be the same as the ammeter measuring the current through any other bulb. An ammeter connected to the battery, measuring the total current, would measure more with each bub.

If you keep adding bulbs, you will eventually reach some limits on your battery.

[thepieface9496]

@derekowens ok thanks, nice videos btw helped me revise for my science test :D

[vibrax7795]

You really tried. You can't beat Khan Academy though. Good job overall, however. This topic is a lot clearer now when it's displayed as a picture in front of me.

[ileos25com]

Imagine he changes the whole time he sais bulbs to balls :D

[asianbejealous]

What about voltage?  How does voltage affect parallel and series circuits?

[derekowens]

@asianbejealous That's a good question, and we go a good bit deeper into that topic in the Physics course. In a nutshell, circuit elements in parallel with each other have the same voltage, and for circuit elements in series, the voltage drops add up.

[Wilson1592]

What are you using as a drawing program, as well as a recording program? Great video.

[fsujs]

hey could ask your advice on how i should wire a project im working on?

[MultiSupermaster]

Excellent and well-explained.

[xoitsmylife]

your SO GOOD at explaining stuff!

[derekowens]

@JustSpecialty Thanks! Yes, that's me drawing!

[intdud]

awesome exp

[4stjohn4]

i wish christmas lights were parallel

[derekowens]

@4stjohn4 These days a lot of them are. When I was a kid they were almost always in series and it was very frustrating when one of them went out.

[4stjohn4]

@derekowens i guess i have old ones then haha.

btw. this video is amazingly helpful. I have a physics test tomorrow and this helped me undertsand the concepts sooo well.

I can't thank you enough!

[icebreaker753]

@4stjohn4 ya same here its a quiz but still

[bilibob32352]

VERY well done

[chapinero017]

what kind of software do you use to teach this?

[mrJTfilmproductions]

thumbs up if you needed this for a school project

[azfryguy]

Series=sucks

Parellel=awesome

[derekowens]

@azfryguy Ha! That's funny. In some cases, that is certainly the case. There are applications, though, where series is what makes the most sense.

[Second2Rush]

@derekowens And @azfryguy

More like, Series = Great! (If you're Running one things on More Battery Power)

Equiling a Stronger Motor power Lets say, Now Parellel = (Bettur, Best) "For the Fact of running more things or just one thing on a Parallel Connected Battery's, For longer Hours.

120mAh ("Milla Amp Hour") + 120 + 120 (All mAh) = Longer Running time for One or 'Some' More Circuits.

120 VAC + 120 +120 ("All VAC) = Higher Power ("As a Electric Motor, For Example").

[azfryguy]

@azfryguy thats what my brother said but still it sounds like series is outdated and will become obsoulete

[LegallyPunjaban4eva]

thank you, you're awesome!

and mann, that first circuit looks complicated :)

[carrefour102]

I must thank u becuzz

This helped me thru my Physics exam thanxxx

[8poopcorn13]

This was very helpful, thank you. :)

What program did you use?

[MtotheAtotheJtotheA]

this is really helpful...my physics teacher recommends your videos to my class

[DjGisME]

if you had 2 x AA 1.5V 1000mAh batteries in series that would give you more volts = 3V but less current available to spend = 1000mAh.

if you dad 2 x AA 1.5 1000mAh batteries in parallel that would give you the same voltage = 1.5V but more current available to spend = 2000 mAh

so series and parallel circuits work vice versa with their values as noting comes for free in electrical vorld

[1234LMAO12345]

indeed. Very padantic.

[MyGameMyWay]

i understand a few concepts, but the resistence and current flow in both series and parrallel circuit confuses me..alot. i don't really understand "resistence". please help.

[chasechase24]

thank you so much! learned a lot

[r4ng1ng0wnzz]

you sound like J.F.K. :) awesome video dude, hugely helpful for me

[Smileypig4life]

nice work buddy i have a science assignment due toomoz and i had no clue about anything

[Rayaarito]

In a simple series circuit, why doesn't the first LED get all the power and blow out? I can't find the answer anywhere. Everywhere they just say that all the LEDs split the total voltage. But if you follow the electrons through the circuit, they are going to have to hit the first LED to get to the rest, so why doesn't it blow out?

[derekowens]

@Rayaarito Here's an analogy: think about a water wheel. It uses the energy (PE) from the water. The water falls, and the PE is turned into motion. Now think about two water wheels stacked up (in series). The first one doesn't get all the water. They EACH get all the water, but the potential energy is split between the two. In electricity, voltage and power are related to energy. All the electrons flow through each resistor, but the energy is divided up. Hope that helps!

[KoshMalek]

@derekowens

thank you so much

could you tell me how did you designed this scene please ?

What is the program that you used?

[strong1235]

@Rayaarito Because the total current is limited by the total resistance of the entire string, so no more current can flow through one device than any other. That limits the total wattage that any one device can get.

[josh71111]

I'm learning this in school, thanks for the help :)

[joceybunn]

Thanks for the upload!

so easy to understand and fast! :D

def thumbs up! :D (Y)

[KraziiSophina94]

You are such a better teacher than mine!!!!!!!!!!!!!!

[ranoooosha]

Very helpful.. thanks alot! what is the name of the program you're using to present the circuits?? were can I have access to it ??

[frank0067]

this is cool stuff.. can tell me what would happen if batteries were put in series and parallel forms... would we get more voltage and amps in series of batteries, compared to parallel ?

[derekowens]

@frank0067 Yes: batteries in series gives more voltage. batteries in parallel gives more current. Hope that helps! D.O.

[InsaneTux]

very educational!

[ghostalin]

What does current mean on the atomic level? Number of electrons*speed?

Forgive me for my ignorance, I am just curious.

[derekowens]

@ghostalin Current is the flow of charge. Specifically, it is the amount of charge passing a given point in a given amount of time. If 1C of charge flows past a given point in 1 second, then the current in 1 Amp.

[usiknotme1]

This is good man very easy to understand thanks

[dycarbon1]

This video has been IMMENSELY helpful to me. THANK YOU VERY MUCH!

[dycarbon1]

I'm sorry but haha man do you sound like George Bush!

[frofro9997]

they got the positive wire from the battery leading to the ground casing and the - wire from the battery connected to the positive terminal on the light bulb. Polarity Fail!

[smellslikepanda]

you are a ledgend.

thank you :D

[adardvd]

THANKS A LOT !!

[MrBagazkara]

thanks! Ireally need this for my Exam!!

[CandiiDuckyy]

At 4:01, I noticed that you drew the electron flow wrong. I thought they flowed from negative to positive? the short line is negative? :)

[derekowens]

@CandiiDuckyy The direction of the flow depends on whether you are talking about electron flow or conventional current. It's an endless source of confusion for physics students. I discuss that in more detail in the Physics course, though.

[adardvd]

@CandiiDuckyy yes the flow goes from positive TOWARDS the negative side of the battery

[elizochoa]

I am a visual person and your drawings simple and clear, very easy to understand.

[licence30]

ure an awesome teacher

[MisterRobotHead]

Thanks for this video. I found you by chance and understand this now. I was having trouble in school. I have subscribed!

[ScorchinBeats]

I have a question. When you have a parallel circuit how do you know which loads will be affected when you open a switch.

[keivan324102334]

hahaha fail at 4:10, he drew it in da wronge direction

[derekowens]

@keivan324102334 Actually, that's the correct direction if you're talking about conventional current. I hear you, though. The difference between conventional current and electron flow is an endless source of confusion for physics students throughout the world.

[brahmdeep121]

@derekowens yea I gotta keep that in mind myself, im taking a intro to electrical course and i noticed the same thing as keivan pointed out.

electrons flow - to +.....

but conventionally its + to - (do correct me if im wrong)

[derekowens]

@brahmdeep121 That's correct. You can imagine electrons flowing from negative (repelled by the negative terminal) to positive (attracted to the positive terminal). That's "electron flow". Or you can imagine positive charges doing just the opposite. That's conventional current. Mathematically they are equivalent. Electron flow is what's actually going on, but electricians usually think in terms of conventional current, which is okay because it's mathematically the same.

[brahmdeep121]

@derekowens Alright, thank you. Our professor rushes through the material, so I'm relying on online support :P

[gyneman]

@derekowens The NJATC teaches electron flow to all apprentices working in the IBEW. They stray away from conventional flow because it's easier to grasp 'hole flow'.

[derekowens]

@gyneman Thanks for the info. I should try to make a video addressing just this one topic. Maybe one day, if I get the time....

D.O.

[ripadisc]

class well explained fuckin brilliant

[ripadisc]

wish you were my teacher

[Bryantzerox]

Everything makes so much sense now...

[werlkaw]

very very helpful thanks.

[Weerzer]

This is great, very easy to understand. Thanks.

[truegwbfan]

jeez all i wanted is to find out how to add resistance in parallel cause i forgot. do you add them together then divide. or do you multiply them togehter then do your division. i already know how to do the denominator.

[derekowens]

To find the total resistance for resistors in parallel:

1. Take the reciprocal of all of the resistances.

2. Add this all up.

3. Then take the reciprocal of that sum.

That will be the answer.

[truegwbfan]

thanks, i found out the answer messing around myself, but your way is handy if you have a calculator on hand. of course there are other ways but but i suck describing them o_O

[tormozmomotok]

Thanks a lot... Simple explanation like this completely made me understand the difference between series and parallel circuits. Something I had problems with before.

[Chubba2394]

thank you this was helpful but should have included info on volatge too..:)

[spottysocks14]

To make it simpler you could just say its a type of circuit where there are alternative paths for the electric current.

[69elchupacabra69]

Khan Academy drawings on steroids. Thanks for posting such videos. Both of you help.

[badgyalbirdieakaray]

im sorry but when you say electron flow u mean conventional current flow dont u ? because ur arrows are goin from positive to negative but electron flow is from pos to negative ..im slightly confused

[derekowens]

Yes, if the flow is indicated as going from positive to negative, then it is conventional current. And the flow of electrons is actually in the opposite direction. The whole issue of the direction of the current flow is, unfortunately, going to remain confusing for the rest of our lives because of this difference in electron flow and conventional current.

[skatingprotagy]

thx for the help im failing science and need to pass my test. This video helped me understand a lot better.

[xoxopinklover]

wow thx so much i understand wayy more in order for me to do my proj do u noe wat materials i can use to make for the wires thing?

[derekowens]

You can get little light bulbs, light bulb holders, wires with alligator clips, battery holders, etc. at Radio Shack. HTH.

[polachb]

Great video. When calculating total voltage in a series circuit, you combine the total voltage of each cell, correct? What about in parallel? I know you don't combine them, but I'm a bit confused about how to calculate. Thanks.

[derekowens]

I don't go into that here, but I do in the physics class. Look at the videos on series and parallel circuits from the physics class and I think that will answer your questions

[ServeAllah]

can you explain how i can work out the current of each resistor in a parallel circuit that contains more than 2 resistors in parallel, because i can find the current for two resistors in parallel using the Current Divider rule but how do i work out the current when there are more then two resistors in Parallel, quick bro please got an exam on Monday.

[derekowens]

For three resistors, R1, R2, and R3, all in parallel with one battery, the voltage in each resistor will be the same, that of the battery. Then you can just find the current for each one using Ohm's Law. I1 = V1 / R1 I2 = V2 / R2 I3 = V3 / R3

The idea is that for resistors in parallel, the current divides, but the voltage remains the same for each one. In the above equations, V1, V2, and V3 are all equal to V, the voltage of the battery.

Good luck on your exam!

D.O.

[ccsupracc]

is it true voltage actually flows from neg to pos

[derekowens]

What we call "electron flow" is, in fact, electrons flowing from the negative terminal of the battery to the positive. What we call "conventional current" is imagined to be positive charge flowing from the positive terminal of the battery to the negative. Mathematically, they are the same. Most people follow the convention of thinking of it as positive charge flowing, even though that's technically backward. It really doesn't matter, though, as the math works out the same either way.

[EjaeWiggins]

I have to take an Automotive Electric class to get into my transmission class. I understand it but what does this have to do with transmissions

[derekowens]

Hmmm.  Not sure. But I imagine there are some electronics involved in the automatic shifting on an automatic transmission.

[rockerresident]

i wonder why does the bulb comes first to switch since the switch is the one allowing the electricity to get into the bulb...and why the bulb comes first to the resistor..since the resistor is the controler of the braking or burning of the bulb..isnt it should the resistor comes first to the bulb because resistor controls the burning? yeah bad english sorry..

i finally understand this diagram or picture haha thanks...

[derekowens]

In a simple circuit like this, the order of the bulb, resistor, and switch does not matter.

Electrons already exist throughout the circuit. There are there in the wires, in the bulbs, and in the resistor. When the circuit is turned on, they start to flow, pretty much all at once. The resistor will affect the amount of current that flows. The switch will determine whether there is any actual current flow or not. This is true regardless of the order.

[computerhelper321]

Very very helpful :) Keep up the good work !

[FreakNashin1979]

I hav always though current was more of a pull rather than a push....is this incorrect?

[derekowens]

Actually, yes, you are right. The force of electricity can be compared to the force of gravity, which is a pull. Still, it's helpful in a lot of situations to think of voltage as the "force" that shoves the current through the wire, so voltage is often thought of as a pushing force. In truth, voltage is more closely related to energy than to force, though.

[snapson7]

shouldnt the electrons flow out of the negative side of the cell

[tubeyouabc1]

Yes electrons usually flow from negative to positive, but I think that he did not yet want to state that point.

[derekowens]

That's right, the , the electrons flow out of the negative side. It's common, though, to think in terms of "conventional current" in which we imagine that the charges are positive charges moving the other direction. The circuit will work the same way regardless of the direction of the current flow.

There are some circuits in which the direction of the current flow matters, but that is not the case with any of the circuits in this video.

[jic647]

yes they shud

[charizardsspirit]

Pff this is so easy...

[louie9349]

in a series circuit, if one light bulb goes out all the other bulbs will not light up because the filament of the bulb that went out is broken and therefore electricity cant't travel any further than where is broken.....thus, it will be an open circuit....this is why home are design in parallel so that electricity travels through multi[ly branches.... making each branch work independently.

[jic647]

hardly anything is done in series

[dr8ken]

in the series of 3 lamps, and the middle one burns out, why does the 1st bulb not light? doesn't electrons still reach that bulb,?

[derekowens]

Yes, electrons are still there. In fact, electrons are always in every bulb. It is the *flow* of electrons that makes the bulbs light, however, and if the circuit is broken, then the electrons can't flow, so all of the bulbs go out.

[j3s0n]

Hello!

I have watched your video, and I understand most of it. The part I do not understand is the "series circuit" section. Mainly the part where you say all bulbs will go out if just one breaks.

Now I trust that the information you give is reliable, but could you please tell me why all of them would go out, just so I can understand this a little better? Because the question going around in my head is "well atleast wouldn't the first one still light up?"

Cheers!

[derekowens]

Yes, I think I can explain this. Whether the bulb lights up or not is not determined by whether or not there is a wire running to the bulb. It is determined by whether or not the electrons can flow, can actually move, through the bulb. In a series circuit, if one bulb burns out, then the flow stops. There is a traffic jam of sorts, and all the electrons stop moving. If the electrons don't move, then the bulbs don't glow.

[coolcorvette]

thanx i was wondering about the parallel and series circuits and i couldnt find it anywhere else, thanx again!

[TheDriveMaster]

You saved my life!!!! THANKS

[kg4wrm]

Thank you for your video.

[DesRecon]

In your circuit diagram where you have done a Loop in a circle for the bulb, Is a circle with an X in it the same ?

[derekowens]

A circle with a loop in it typically represents a "lamp", that is, a light bulb used for illumination.

A circle with an X in it typically represents an indicator light of some kind.

[brandoo10]

thank you so much for making this video i have a question for school i was stuck on now it makes so much more scence your the best!