Boolean Logic & Logic Gates: Crash Course Computer Science #3

[@crashcourse]

*CORRECTION* AT 1:27 the graph says "Quinary System" but then the graph shows 10 possible states - which is actually decimal. Technically, there should be only 5 possible values there, but the overall concept is still the same. NOTE: Since we can't use annotations in our videos going forward if we find any smallish errors in our videos like this we'll leave clarifications in the episode description. Thanks all for the wonderful feedback! -brandon

[@rikenm]

pin this comment,CarshCourse. It is away down that no one will see it.

[@GLTDubstep]

Why can't annotations be used going forward?

[@hotdrippyglass]

Using annotations in the future videos will be much more difficult because they are going to be going over much more complex levels of "abstraction" as she calls it. In this and the previous videos the 'units of discussion' had to do with ones and zeros and those only in pairs at most. The next level of discussion is going to be about arranging groups of eight, sixteen, thirty two and sixty four. Correcting minor errors in the video with annotations will need three or four minutes of reading and that will interrupt the flow of knowledge a person can retain from the video itself. At most I could suggest an annotation that an error is corrected and that it is explained in detail in the show description. Larger errors would require rewriting and rerecording the entire episode.

[@brandonbrungard8418]

Annotations cannot be used in conjunction with the endscreen tool - it's just a limitation of the software. And since annotations don't work on mobile anyway, it's better if we have a place for those corrections and clarifications that are accessible on all devices.

[@TheMasonX23]

CrashCourse I'm guessing this mistake is related to Tommy Flowers' Colossus using a "biquinary" decimal notation.

[@darkBender99]

I am a third year majoring in computer engineering and this video explains transistors and logic gates better than a semester class.

[@C0deH0wler]

Nope. It's more nuanced than that.

[@Nymmastan]

to be fair though it is an over simplification to what we learn in computer engineering, Such as the explanation of the NOT gate does not technically work for what the NOT gate is

[@BirdRaiserE]

Huntson It explains WHY better, but not how. If you want the how, you need the math.

[@IceMetalPunk]

+nollid3 Well, it does work, it just...doesn't work very *well* :P Perhaps a future episode will get into CMOS and the like? (Seems doubtful now, but you never know!)

[@ThisIsReMarkable]

Woo! They say that you don't truly understand something until you can successfully explain it to someone who knows nothing about it. :) Edit: And by that I mean, if someone just stumbled on this video, they would have an idea of how computers work better than before they watched (Not to say you nothing about it, Huntson. hahaha! Oh words)

[@TheGenericNerd]

Oh my god, THANK YOU for clearly explaining how each logic gate is physically represented in an electrical circuit. A lot of that abstraction makes it really daunting and hard for dummies like me to get it through our thick heads.

[@Tfin]

I felt they could have stuck NAND (and maybe NOR) in there, before XOR. Just because it would have been easier to have the constructed NAND ready to help build the XOR. Never mind that XOR can be built entirely from just NAND or NOR.

[@IceMetalPunk]

But to be fair, NAND isn't something laypeople hear about or think about, so using the logically equivalent "not and" makes the connection easier for many viewers.

[@vlogbrothers]

Bit at the end made me wonder if I'm merely a computer. Great episode! -John

[@FewMinuteProgramming]

There are 10 types of people in the world, those who are are secretly computers and those who aren't.

[@maggiehall8501]

I'm so happy with how the crash course series has expanded. I was blown away by Crash Course World History and never really imagined how many different courses might be visited by crash course videos but it is awesome. As an engineer, I know that breaking down topics like computing into manageable chunks for younger audiences is essential to the coming generation being successful in the increasingly computer based work force

[@FewMinuteProgramming]

Hey Maggie! Now that you bring it up, would you mind giving me feedback on my videos? I make CS videos for children and I try my best to keep the kids excited to learn!

[@C0deH0wler]

vlogbrothers We are biological computers. 'Merely', I think, is not the right word to describe this nature. I would personally omit 'merely' if I ever wrote that.

[@TheOlFlat5]

psst.... You are 0_o

[@MFMegaZeroX7]

A good video as always! As a CS major myself, this is actually finally a series where I can answer questions and stuff in the comment section! Just a pedantic note for people who want a little more info: 1) There are also not versions of all the gates. AND, OR, and XOR become NAND, NOR, XNOR, respectively. They are represented by adding a small circle to the end of the gate. While they can be formed just by adding a not gate at the end of the inputs, they are common enough that they get their own specialized parts. You often here people verbally NAND and XNOR when talking about logic, so I think it is interesting to note even though this isn't computer engineering. 2) While by convention in truth tables 1 is true and 0 is false, this is often not the case when we actually look at real components. Because of power usage, the opposite is often used. Generally, the more common output is set to 0. 3) 0 doesn't actually mean nothing is flowing through. For example, we may set our 1 to 5 volts, and our 0 to 2.3 volts. This allows for us to have an "off" state at 0 volts. We wouldn't want our computer to be calculating stuff with 0s when it is off! There are also other uses for this state, but this may be covered in a future video.

[@IronLotus15]

Interesting.

[@firenationfiles2063]

Intriguing

[@DA-li6dp]

Thanks!

[@joemomumbo]

How does a not gate work when input is 0

[@riiad]

Thanks a lot for that comment. As for the 3rd, it was made clear in the video. But the way i understood it was that you can use a range for the system to be more reliable. For instance : 1 to 3 volts are 0 5 to 8 volts are 1. Of course i don't know anything about voltage yet, so i chose those random numbers just to illustrate my understanding. Is it how it works?

[@Outwars1]

She is a VERY good teacher. How she breaks it down so you understand the details and then subtly tells you about application of abstraction helps you focus on whats important... she makes actual little building blocks for you as she speaks.

[@TheBrothersBlue]

Unlike most CS introductions, Crash Course does a great job in giving the student context, explaining how computers function at a fundamental level before applying layers of abstraction. Very well done -- As a Sophomore ComputerSci major, I'm excited to see more enriching content every week(:

[@BlankPicketSign]

My first real exposure and application of logic gates was in Minecraft with Redstone

[@ゾカリクゾ]

not gate = block powered with redstone with torch on top

[@Kurosaka]

true true same here

[@naeem6583]

Anybody saw that Creeper?

[@whimsicalcookie1426]

This is completely true for me as well.

[@Pashmotatoe]

There's a creeper in the background too

[@SirCrest]

Just wanted to say I love the themed animations for this series. The computer UI, old Mac OS UI, etc. Always great work to the animators and team.

[@AtomicPiggyGaming]

Look at this nerd

[@FewMinuteProgramming]

Me too. Brings back some nostalgia.

[@jorenmartijn]

I've always been interested in UI design. Not only in conventional computers but also in video games and game systems for example.

[@Thought-Cafe]

Thanks for the love! We always appreciate fans recognizing the hard work that goes into designing Crash Course. -James

[@DanAlmenar]

Dear lord, didn't know Thought Café had a profile/channel on their own. Going there asap!

[@deathdoor]

Just passing by to say that I'm loving her course and excellent diction.

[@majordelays4909]

She sounds similar to Dobbie from Peep show...

[@BlackXxScopez]

I used to make cpus in minecraft, and it's amazing what it could teach about computers. It makes you feel like you understand exactly how computers work, and in a sense, you do. programming using only 1s and 0s, creating all of the logic gates/decoders etc from scratch, optimizing, and attempting to add a second core. I've moved on from Minecraft since then, but it's a great tool to make use of if you have the game and want to go deeper into boolean logic/logic gates and computer architecture. The hardest part is creating an Instruction set that is powerful enough to let you program basic programs but easy enough to decode to keep you from ripping your hair out. generally, It would be a non-pipelined CPU running at about 0.7 hz, but some made optimised pipelines that allowed speed of up to 2.5 hz, which is amazing given that every transistor take 0.1 seconds to switch, and after a certain range, you must add a repeater, which re-strengthens the signal, which also takes 0.1 seconds.

[@IceMetalPunk]

Redstone is what got me interested in Minecraft in the first place. I'm a computer scientist (fancy way of saying "programmer with a degree"), and my friends introduced me to the game by saying "It's like Legos, but you kill stuff". I wasn't interested. A few years later I stumbled upon redstone, and was immediately hooked (and still am!). Creating what are basically electronic devices using a relatively limited set of components, all of which are 1 cubic meter at a minimum, brings out some serious creative juices. And then there are command blocks, which are sort of like a limited, spacially-oriented scripting language... I just love it

[@StalePhish]

Minecraft should be used in schools to demonstrate logic gates! (I'm sure it is but probably just in a handful of places). Some of the first redstone devices I've made were based on AND and OR gates. I have a computer science degree but I think this video demonstrated the concept quicker and better than any class I've ever taken.

[@TheOsamaBahama]

I once made an automatic subway station in Minecraft (the carts exchanged places between stations automatically as soon as you entered a cart). Than I saw some people made mechanic calculators in the game and it blew my mind.

[@yourcurtainsareugly]

I never could get into Minecraft. Dwarf Fortress ruined me :D The computers made in DF are pretty incredible. I remember taking my class in computer architecture, using Quartus to build a CPU. Props to anyone who can do it in a game.

[@rcookie5128]

yeah I did a basic redstone calculator too, thats how I learned it .. ^^

[@comb528491]

As an Electrical Engineering Student who was always curious about how Boolean Gates worked, my life is now complete...

[@anti_MATT_er]

I was wondering where I'd heard Boolean before, then realized that I took a logic class last semester. :D

[@FewMinuteProgramming]

It may have also been from a discrete math class if you've ever taken that!

[@3John-Bishop]

There is Boolean algebra too, look it up

[@mrmimeisfunny]

Yeah, I had a vague recollection of a term. It was one of the main topics from a lesson i took.

[@slightlybored]

hahahahaha that's so true

[@florianmarcher]

That sounds logic to me

[@TheQballChannel]

That feeling when you literally have a test on this tomorrow

[@BirdRaiserE]

Qball , Uc Davis? Probably not, but what's the class called?

[@TheQballChannel]

Nah its just a programing class in my highschool :)

[@TheQballChannel]

Thanks. I did pretty well and Its a really fun class. I do kind of take it for granted. I now appreciate the class much more :)

[@candii1246]

I have my GCSE mocks in avfew hours ｡･ﾟﾟ･(>д

[@danialsaeed1083]

hmm mee 222!!! have a test 2morrow :{

[@eddiehimself]

I mean the fact that George Boole came up with Boolean Logic a century before it became a vital component of designing computers is pretty incredible. It just goes to show how the discipline of pure mathematics, that is studying mathematics not for a practical purpose that is known at the time, but just for the sake of expanding the scope of maths itself, can really pay dividends when the technology catches up with it.

[@TTKChristo]

As a CS grad that graduated over 5 years ago, this video had me giggling and remembering many classes, thanks!

[@Leyshire]

Physical basis of logic gates wonderfully explained!

[@BarisPalabiyik]

I have took electronic design in highschool, in college and in university as ee engineer but this explanation would be so easy to understand at the begining. Great job as always cheers.

[@eifelitorn]

Man I used to study CS a few years ago, love how you can learn all I learned in months in a few minutes. Great job !

[@Baby_boodle]

I'm so happy this channel exists. Thank goodness it does.

[@ゾカリクゾ]

actually thank pbs...

[@АнатолийАнатолий-п1д]

The feeling when you don't have any exams tomorrow, but are doing it for fun and now the whole new world of Computer Science has opened for you to learn and become a master of every computer you'll ever meet in your life.

[@movin2585]

Carrie Anne is effortless and brilliant. She made logic gates delightful. More please.

[@pinklady7184]

I cannot believe I have learned NOT, XOR, OR gates and all other jargons in just few minutes. Please keep making more videos on computer science. How about videos on programming languages, electronics and mechanism? Your brilliant videos make our small brains balloon up.

[@matthewrobbins5493]

Have studied computing for 4 years and never seen how logic gates are physically made with transistors, really awesome video!

[@FewMinuteProgramming]

Wow! I love these videos. It's amazing how far we've come with computers.

[@MrAndyisReal]

Woah, I see you everywhere!

[@chichi-nm8kn]

Few Minute Programming no its not ;)

[@Kopellis]

Two and a half years into electrical engineering and now in this video i learn these stuff. Really well done!

[@jdillon8360]

Carrie Anne is the best. So good at explaining these concepts clearly and with a little humour thrown in as well.

[@PilotPlater]

I appreciate that this video relates it to actual transistors and not just starting with the arbitrary principles/symbols. Relating it to the real world is important.

[@Scorpio8116]

The circuit explanations would always go over my head when I learned it in class and I just skipped over to doing the gate symbols for everything. But I think it FINALLY clicked when I watched the circuit diagrams in this episode. Really nicely animated!

[@jokerwanted]

Having completed a Bachelors degree in Electrical Engineering, I do not remember ever learning the internal transistor make up of the gates, just what the gates do. I am enjoying this series a lot, keep up the good work.

[@JackFou]

Loving the casual reference to "Journey" aroud 0:50. Such a great game!

[@amadouirving]

As much as I hate the complexity of these videos, I love how much I'm able to learn from them. And I believe I'm speaking for thousands.

[@lordkingsman2minecraft810]

Minecraft redstone already taught me this

[@bean420man]

Thanks for explaining this to me. Got a test tomorrow and this is part of it. Anyone wanting to be an aircraft mechanic, take heed. This is part of the curriculum.

[@JohnMillner]

I'm so glad you're making this series, this will help more people understand the concepts and fundamentals behind computers and computer science :) I'm dual majoring electrical engineering and computer engineering and while I already know all of this content from my courses, this series is absolutely fantastic and I wish I had it when I was going through my early classes. This is something I could definitely see good professors showing in their classrooms before getting into the nitty-gritty math

[@jpalo7733]

This explained what Fullsail seemingly struggles to teach with ease! Carrie Anne, you and the writer deserve better than a simple youtube spotlight. Grazie

[@javahusky24]

This is really amazing, you have answered so many of my questions in this series so far and I am excited to see more videos in the future!!

[@tommrutherford]

Software engineer here; this series and its explanations are really excellent. Great job!

[@davidtaylor789]

You are amazing. I have always been fearful of this information. I see now i was fearful of the instructors. Where you are concise, cheerful and fun they were scattered, drool and resentful. Thank you for knowledge!

[@munthon]

These series needs more views. Too few people nowadays know basics of how computer works.

[@munthon]

And boolean algebra helped me in set theory calculations when I figured out they are the same, just different names.

[@dorothyglade9087]

omg love the Journey reference!!

[@robertbilling6266]

I've been 40 years in the industry, and I learned to program (in assembler) from a PDP8 manual back in 1967. Congratulations on making a complex subject very approachable. Curiously the good old 6800 microprocessor had a "half carry" in the status register, and the DAA instruction specifically so that it could work with two decimal digits to a byte (BCD). If you were using it to implement something like a cash register it was easier to work in decimal than convert to binary and convert back.

[@moonwasabi]

loving the series! wish i'd have had this to watch before starting to study computer science :D (i just finished the first semester) you're doing a great job at breaking the subject matter down and making it interesting! i'll be forwarding this series to anyone asking me what i really learn about!

[@dauf69]

She has gotten much better compared to the first 2 episodes. Keep it up Carrie Anne!

[@guyfox7337]

Boolean logic came from a professor at my university, University College Cork (UCC) in Ireland. His name was George Boole. He's very famous here. Our main lecture theatres as named after him. Along with are library. Funny fact about him is that he died after getting a cold because one day when it was raining he forget his coat. Anyway I hope this piece of info helps in your studies of Boolean logic.

[@tiarnan97]

guy fox do UCC do a level 8 comp sci course?

[@maty5152]

I never would have guessed how useful my intro to logic class is when it comes to this aspect of CS. I'm so glad I took that class.

[@HaydenH]

Minecraft Redstone is just like real life.

[@johnmorgan4368]

I already knew at a basic level how AND and OR gates worked but I never realized before watching this video that the difference between the two is basically transistors in series vs parallel. That is super easy to remember.

[@captaincrab2862]

WHY CAN'T SCHOOL BE THIS SIMPLE!?!?!?!?!?

[@devincross3295]

Oh my god FINALLY a video that actually explains what's on the inside of logic gates and how they physically work instead of just on a theoretical level

[@vitamindubya]

Not wearing pants means something very different in England

[@klins061]

I got my Bachelor of Arts in music a few years ago. But I just applied and was admitted to my city's university for postbac study. I'm deciding to switch and pursue my Masters in computer science. I'm already deep into my essential high level programming knowledge and learning more about discrete math, but also watching these videos is super helpful! I start classes this summer.

[@benaaronmusic]

"Try turning it off and back on again" Great sign-off. :)

[@sarahk689]

I'm currently in my first year as a software developer apprentice and we do learn many of these things in school, for example logic gates. But this series is so damn helpful for me since we never really discussed the origin of it all, or why exactly we need these gates. knowing what role a specific topic plays in the field you work in and its physical basis makes it so much more interesting. thank you so much for the work you put into these videos!

[@Cosmicmoss]

Neat pickup line: "If I were to ask you to go out with me, would the answer to that question be the as the answer to this one?" XOR gated!

[@IronLotus15]

lol

[@discretelycontinuous2059]

Infinite recursion?!

[@The_Pariah]

"Those aren't the official names but that's how I like to think of them." I love this series so much lol!

[@PendragonDaGreat]

It would have been really neat if you had gone a little deeper and talked about the NAND or NOR and they are functionally complete on their own can build up to any of the other logic gates.

[@periwinkle43]

I love this fact. I was introduced to it in my Introduction to Computer Science class and we had a project with a logic gate emulator to build other gates with only NAND gates.

[@jamesinman9262]

JJar43 was it NAND Game?

[@mathandsciencerocks]

The sound effects accompanying the currents/ON/OFF/logic table animations make me so happy :)

[@Funnywargamesman]

That Journey shout out.

[@Rooster1508]

I studied Boolean Algebra in school. I understood it. Only used it once in my work on a real problem . It worked beautifully to reduce the chip count in my circuit.

[@ahnmichael1484]

That was both the longest and shortest 10 minutes of my life :'O

[@crossfarm4146]

I HAVE BEEN TRYING TO FIND A VIDEO THAT EXPLAINS THIS CONCEPT IN A SIMPLISTIC MANNER AND YOU ARE FINALLY THE VIDEO THAT DID IT FOR ME!! THANK YOU SO MUCH!!!

[@NeonsStyleHD]

Very useful for those who love redstone.

[@aboxinspace]

I absolutely love this course, and would like to thank you guys for one extra feature that most channels don't care for: subtitles!!

[@Zerrotox]

Journey!!! Awesome reference!

[@idseungmo89]

Zerrotox haha knew somebody recoginized this as well!!

[@Leoramosis]

I'm currently doing a coding bootcamp and studied a whole section of boolean logic. I felt like I understood pretty well but I also felt like I was missing something. Watching this filled in some of those blanks and made the whole this make so much more sense.

[@jamesjemima7737]

Carrie Ann is beautiful! Although I consider myself a veteran of this material, nonetheless my attention is captured and I find the journey up through these layers of abstraction from the flowing of electrons to the touch pad interface I am using at this very moment quite refreshing.

[@KanuToCL]

6 months of class in 10 minutes.. this video is truly great...

[@peterwalkington1412]

Brilliantly explained! I am really hoping you will talk about more theory like Turning Machines and finite automata

[@MFMegaZeroX7]

I doubt this will get covered honestly. This stuff is usually reserved as an upper level CS course, and this course seems like it will basically be the equivalent of the Computing Fundamentals course my university has Freshman take.

[@vaibhavgupta20]

Automata or Autonoma

[@ShamrockSquid]

I'm so happy you guys have started making this series, as a first year computer science student, it's helping a lot in the bits that I didn't quite understand in lectures. Thanks guys, and keep up the great work!

[@VictoriaCaswell]

My former university held a festival dedicated to Boole, I now know why!

[@stachowi]

Victoria Caswell cork?!

[@vezokpiraka]

Carrie is such an amazing person. I wish she narrated half the stuff I find on youtube.

[@612Tiberius]

THE LOGICIAN I leave you with this conundrum - Boole me this, Fatman: "I am a liar. Everything I say is a lie. I'm lying." Compose a coherent logic gate output using that set of input statements before the auto-destruct countdown goes from 30 seconds to zero and both you and the Boy Dunder are... deleted from existence! LOLOLOLOLOL!!!!!! [exits with henchmen AND, NOT, OR and XOR as the countdown begins]

[@MakeMeThinkAgain]

Just add a NOT to each statement.

[@612Tiberius]

Curses! Why do I keep letting you know how to escape my comically overwrought deathtraps, then leave before they do the job?! However, I must give credit where due,... nicely done, Coding Crusader.... No matter - I'll get you in the Part Two episode! And your little subroutine sidekick too!! Until then!

[@BirdRaiserE]

612Tiberius I"m not a Bat-fan, but I know there's a few out there who will really like this.

[@chichi-nm8kn]

so is it foole me not batman or and xor?

[@612Tiberius]

No - it's Boole (verb), as in "to Boole" - to use Boolean logic (hence the archvillain name "The Logician") to solve a problem, borrowing heavily from "The Riddler" M.O. and catchphrase "Riddle me this".

[@Zenith1867]

As a Newbie Computer Science student,I can say this video is really helpful.Thank you❤

[@gamershawker5558]

"a robot dog must always bark at a squirrel, as long as it does not conflict with laws 1 and 2"

[@TheFamous35]

A natural teacher. It's reminding me of a few semesters back.

[@jlittlenz]

"In computers, an 'on' state, when electricity is flowing, represents true..." IMO this is at best misleading; in practice, it might be the other way around, but much more usually *voltages* represent states, and so bits, not currents. But many electrical and optical representations of bits are used in computers

[@jonasga]

Your entire statement is at best mostly incorrect.

[@nekkowe]

+Jon Asgaeroth Not at all. On/Off states are usually represented as a higher and a lower voltage, not the presence or absence of a current. Optical representations of bits is probably in reference to optical fiber.

[@IceMetalPunk]

On the other hand, thanks to Ohm's Law, we know that V=IR, so no voltage equals no current, and high voltage equals high current, so your objection is mostly pedantry.

[@hg-ir8tb]

Actually, the most common technology used in integrated circuits is CMOS, a complimentary set of p- and n-type MOSFETs. We can use this technology to minimize the potential difference between low resistance paths and maximize the resistance in paths with high potential difference. Since V in Ohm's Law actually refers to potential difference (or the change in voltage), this means that our current I is very close to 0 (somewhere in pA?) whether we are in a high voltage state or a low voltage state. To give you a better picture of what I mean by V in Ohm's Law actually refers to potential difference. Imagine I hook up a 1-Ohm resistor to two 9V voltage sources on both sides of the resistor. The current through the resistor and the current supplied by the voltage sources is zero (assuming ideal conditions, more specifically, that the 9V sources both are exactly 9V.)

[@MeatJigglingZombie]

I agree. In EE there is this notion of active high and active low, which this video overlooks, and every electrical component uses a different scheme.

[@ritveak]

I am in love with this series, I think I should set a date to watch this series every Year !!!! It is super refreshing to see and realize how it all started and obviously unravel all the levels of ABSTRACTION :)

[@MattiaBiggMattGentile]

This is SO GOOD!

[@bluehiker07]

As a beginner with Python, this video blew my mind. Helped the lessons make more sense.

[@Diosjenin]

0:50 Nice Journey reference!

[@lily96flowers]

You teach so much better and clearer than my current instructor who is so disorganized and confusing!!!

[@paulsondumbbells150]

trust me, you're not early. message from the past future.

[@stupidrainbo]

I will liked this comment

[@raymarshall4809]

I truly love this series. and really all of the programs here on Crash Course. The re-enforcement provided here is amazing.

[@sion8]

The quinary system doesn't seem rightly represented, I mean in that system the only numbers posible (using our current Indo-Arabic numerals) would be 0, 1, 2, 3, 4 (or 1, 2, 3, 4, 5). Yet the graphic at minute 1:25 uses all Indo-Arabic numerals which would mean is actually decimal and definitely not base-5!

[@ZamanSiddiqui]

sion8 Yeah, they should have just used the numbers 0-4.

[@MetaBloxer]

I don't think they were referring to the quinary system at that point, just a system with more than two states.

[@skyr8449]

no, it is, look at the top

[@sion8]

MetaBloxer It literally says "Quinary system" on top of the chart before they show why Binary is better.

[@MetaBloxer]

I'm going to break the rules of the internet and admit to my mistake. Sorry!

[@yellostallion]

As a EE and CS graduate, I love these videos!

[@paulgraddon2655]

5:10 I thought you were brave for going commando, but no pants or trousers? I guess that's why we can only see you from the waist up?

[@JDSleeper]

I'm a Librarian and I use Boolean logic to build searches. But I didn't know how it applied to the actual hardware of computers. I learned something new today.

[@nanjayo8970]

that journey easter egg tho

[@Nshiime]

you deserve a nobel prize.4 university professors taught me this but i have only got the point from your video

[@LifeLongArtist]

My brain hurts

[@MarkZetsu]

I'm in love with this series. Hat off to Ms. Carrie Anne, her explanations and engaging methods are superb.

[@HarutoKaizaki]

first few seconds i was like " -__- " and then i was "

[@alwinpriven2400]

I think this is the first time Crash Course teaches me something I've already learned, because before, I've watched Crash Course *before* learning about it in school, and then returning later for more info.

[@masterplayer5982]

Your “and fortunately” sounds like unfortunately!

[@milquetowst]

Your "unfortunately" sounds like and fortunately.

[@caiooliveira1890]

I'm a computer engineering student and I'm just in LOVE with that!

[@asaphkalala]

What about NOR, NAND and XNOR?

[@williefleete]

Asaph Kalala same function except inverted, eg with a "not" on the output

[@AvailableUsernameTed]

or SNOT, SNOR, SNAND and err nevermind .

[@miney046]

I have a physics exam tomorrow morning, and I was off for all the lessons regarding logic gates, so I just found out they existed today. Gotta love high school

[@Tinylinden]

when they say "if you're in England" and use the union jack, like the english flag is the St George's cross :(

[@alexwang982]

TINY Linden What The English flag is the flag in eggland right? You also use the English union jack

[@IFEARALLAH]

This is the best course i've seen. I've learned so much in 10 minutes, thanks for the explanation!