001. Circuits Fundamentals: Definitions, graph properties, current & voltage, power & energy

Introductory Circuits and Systems, Professor Ali Hajimiri
California Institute of Technology (Caltech)
chic.caltech.ed...
Circuits fundamentals derived from EM, definitions, circuit conditions, graphs (nodes, meshes, and branches), current, voltage, power and energy flow.
© Copyright, Ali Hajimiri
160927

[@AnujShahshahmanuj]

Time Stamps: 0:00 = Overview 2:40 = Maxwell's Equations 19:39 = Symmetries, Conservation Laws 26:35 = Special Cases of Maxwell's Equations 33:59 = Branches, Nodes 40:58 = Loops, Meshes 45:20 = Series, Parallel 48:09 = Charge, Current 55:34 = Voltage 1:00:50 = Energy, Power

[@crazyiananderson6676]

Thank you!

[@user-iq1bn6fr3f]

Thank you

[@JordanEdmundsEECS]

I had no idea an introduction to circuits could be so beautiful.

[@AliHajimiriChannel]

I am glad you find it interesting.

[@pyrokinetikrlz]

Excellent lecture! No doubt those were taking place in Caltech. We are priviliged in this day and age, where everybody with an internet connection can witness a Caltech circuit lecture!

[@ianz.0]

after listening to your lecture I was like " how many years would it take for me to teach like him?" . it is very beautiful. Thanks a lot for providing us this lectures.

[@AliHajimiriChannel]

Thanks for your kind comments and you are welcome.

[@ohboy4784]

Excellent lecture. The way you are trying to develop the "intuition " in your students by letting them understand how things "work" and why, beyond the "dry math and equations" is the best way to teach. I appreciate it a lot :)

[@SePidEh2024]

as an Iranian girl who pursuing my education , your level of teaching is impressive. go for the rest of the videos 2024

[@deepakmecheri4668]

This is a feedback from my side on the whole Introductory Circuits and Systems course uploaded by professor Hajimiri. Professor Hajimiri is the teacher I always wish I had. He knows his stuff. The fact that he is an excellent engineer with numerous patents under his name makes sense as only such a skilled person could pass on technical intuition as seamlessly as he does. The method of introducing Heaviside operator as an introduction lays solid groundwork for the laplace domain analysis. Laplace transform finally made intuitive sense for me from watching these lectures. I would encourage anyone who is planning to watch the whole course to go for it - I'm right now watching the Analog circuit design course playlist which is also really good.

[@timk2572]

I Like this type of physicists. They are seeing the nature laws deeper, just beyond the standard way of thinking. True doctor of philosophy. Bravo Ali! I wish all the lecturers would have similar perception

[@mohammadrezaarabieh7743]

Brilliant 👌👌 I was wondering how someone who's major is not physics could be such dominant in underlying physical phenomena !! Tnx prof hajimiri for providing this high quality lectures 🙏

[@michalbotor]

(44:00) if anybody is interested, that is the euler's formula for planar graphs in disguise which states that in a planar graph the number of vertices v minus the number of edges e plus the number of faces f is always equal to 2. in short v - e + f = 2. now apparently in electrical circuits vertices are called nodes, edges are called branches, and faces are called meshes, and the external face is not counted. so that is why we have a 1 instead of 2. and the way that i am able to convince myself about its validity is as follows: i imagine a planar graph that consists from only one vertex without any edges (base case). in this case i have v = 1, e = 0, f = 1 and the formula holds as v - e + f = 1 - 0 + 1 = 2. now i think about all the possible ways that i can build a bigger planar graphs out of this basic one. and it seems to me that only two operations are valid: i can either: (1) connect two existing vertices of my graph with a new edge, or (2) add a new vertex to my graph that is connected with a new edge to one of the already existing vertices in my graph. please note that just adding a new vertex is an invalid operation as this would not create a bigger planar graph but create a new separate one instead. in the (1) case i have: v' = v, e' = e + 1, f' = f + 1. (the last equations stems from the fact that if i connect a vertex with itself i create a loop and this loop has a face (for bigger graphs with multiple vertices there is probably going to be no loop but there is going to be a sort of triangle created that is going to have a face as well)). in this case i have v' - e' + f' = v - e - 1 + f + 1 = v - e + f and the formula holds as i reduced it to the base case. and in the (2) case i have v'' = v + 1, e'' = e + 1, f'' = f. in this case i have v'' - e'' + f'' = v + 1 - e - 1 + f = v - e + f and the formula holds as i reduced it to the base case as well. it is probably not a strict proof, but i believe that at least gives some intuition for why this is true.

[@AliHajimiriChannel]

Very good. Excellent!

[@540madhu]

Thanks Sir Mr.Ali Hajimiri. The way you started class with Maxwell equations ..I am impressed .. To day I decided that I want finish both of your lecture series.. After so many days I am seeing my professor in you.

[@AliHajimiriChannel]

Thank you for your kind remarks. I hope these lecture help.

[@meylism1825]

After watching some of the lectures started to think "Did prof Hajimiri attend IPhO?". After googling, found out you did attend IPhOs, I can feel the "taste" in your explanations :). Thanks!

[@parsimahmood521]

amazingly picturing a complex topic in a very simple way. It is really rare to listen or watch circuits course and enjoy, but this one is different

[@AliRaza-tv7yf]

Prof. Ali Hajimiri thank you! for these wonderful lectures clear as crystal, may god bless you.

[@awesomeswordsman8231]

thank you a lot sir, not only did i need a lecture on circuits but you've also given me a nice revision on physics, and explained some things i didn't understand in my first semester of college in physics class, i never understood that upside down triangle until now

[@reginaldlourdraj9037]

I'm a mechanical engineer with a decent math background. I find your lecture extraordinary! So much of information in one video!

[@programmingfunda5788]

One of the best lecture I have ever come across. You're born Teacher. Keep sharing. I would be happy you can share more on explanation of Maxwell's law and interpretation of them.

[@gurkanerbas5]

Literally great .. I really appreciate your inspiration in understanding the details I have known for years .. I hope there wıll be more lessons you teach in youtube..

[@abbask56]

What an amazing intro for circuit fundamentals... wow!

[@eng.abdalrahman2583]

ماشاء الله تبارك الرحمن واحدة من اجمل المحاظرات التي رايتها عن السيركت بارك الله فيك ووفقك يا استاذ

[@kabandajamir9844]

The world's best teacher thanks

[@krishanudebnath1959]

never understood Maxwell's equations so Crystal clear

[@Mirsab]

This makes me want to go to Caltech

[@thilohesse8883]

That would be pretty cool, wouldn't it?

[@xiangbocai-ns4sg]

I think before you dive into this course, you have a strong fundamental knowledge of math, electrics and magnetism physics knowledge. As a freshmen, I appendix my math and physics for 1 month then I look this course video, anyway, it is beautiful

[@newb_embedded040]

Is there any home work or assignment for this course ? If yes, from where can one find those ?

[@user-vb5hw3on8k]

Are there any textbook or recomended textbook for this unit?

[@hajerjm]

Dr, thank you for a very interesting and helpful course. Your lectures are full of information I wondered, if you could share with us your own lecture notes or slides, please?

[@mohammadrezaarabieh8811]

I enjoy the way you teaching ... it was perfect Good luck

[@AliHajimiriChannel]

Thank you.

[@anjishnu8643]

The art of teaching science.

[@bibekdhungana2182]

Thank you so much for such an amazing lecture.

[@harveyyoung3423]

A comment on part 2 of the lecture. Something strange happens to the narrative when Prof Ali Hajimiri moves on to discuss circuits and networks in the second half. Here, nodes have a potential differance, branches have a current flowing through them (except bottom left perhaps). Now, as a condition of the possibility for any electrical phenomena, any current there must be a potential differance. But this means that then electrical phenomena is conditioned by an asymmetry of space and time, while its "high level Maxwell equations are supposed to govern it universally, which themselves are meant to be governed by the symmetries of space and time. In a sense the two conditions governing electrical circuits, high level "regulative ideas" (symmetry) (Kant), and concrete binary relations (potential differance asymmetry) (Hegel), contradict eath other. Or it could be said that the meaning of the electrical concepts from the two standpoints are in conflict with eachother. Great lecture Prof Hajimiri, but my guitar amp project is not going so well.

[@SePidEh2024]

amazing , enjoy it 2024

[@nimamoeiny5831]

We all Proud of you bro and god bless you.

[@engrabdinasir7989]

Dr. thanks a lot for given us this organized lecture.

[@abdulwahabalazemi1418]

Thank you for this lecture video and the other videos that helped me to memorise the materials I took at university that I thought forgot them and again thank you for the lectures

[@harveyyoung3423]

I came here for some electronics background as I am trying to build a guitar amplifier, as a covid break from working on the philosophy of Kant and Hegel. Not what i was looking for exactly ,for the amp build, but the moves from Maxwell's equations through conservation of charge and energy to symmetry principles of space and time was very interesting and unfolded through a very nice narrative procedure. But is their no escape form the Kant/Hegel loop?

[@user-qf8bt9ws4k]

you are good doctor

[@eecm23]

Hello professor, I just want to thank you and appreciate you putting the lectures on here but is there a book you would recommend to go with this course?

[@mmh1922]

An amazing lecture!

[@hardiksarraf1221]

thank you sir for providing this knowledge its really healpful🥰🥰

[@mazenelgabalawy3966]

Sir, What are the prerequisite courses for this class?

[@EEShyama]

Is there any supplementary material or a recommended book that can be followed along with the lectures?

[@aliibrahem3691]

Great stuff

[@yousifhazem1416]

Thank you for your efforts, it was great lecture...

[@patrickngakou2328]

Please what the name of this book that’s you use ? 41:06

[@arashmousavi]

Very nice teaching. Thank you very much for this course. Is there any accompanying materials such as recommended exercises?

[@oseyedian]

خیلی زیبا بود

[@aedty9844]

Where we can find homework problems for this course?

[@AliHajimiriChannel]

Unfortunately, they are not available outside Caltech at this time.

[@saminchowdhury2509]

Maxwell's equations alone can make a man forget himself at times! ;)

[@kingrobert7246]

for guys who have watched the whole series, ive covered some basics of electricity but is this worth going into

[@hajer5477]

What's the textbook used for this course, Dr?

[@AliHajimiriChannel]

Linear Circuit Analysis by Artice Davis. However, there are parts of the class not covered by the book.

[@navamoore]

Is there a way to get this course syllabus to see what book is used for this class?

[@mohammadrezaarabieh7743]

Prof do you have any textbook recommendation for this course ?! Tnx 🙏

[@gameofgrit9]

sir,As of now,our Institute is preferring Fundamentals of engineering by Leonard S.Bobrow, can I follow these lectures so that I could cover the topics in our book?

[@onlynonsense8723]

Is this a pre-course to this?

[@oximas-oe9vf]

these sound complicated are there any prerequisites that I can learn before taking this class note: i studied high school physics, math and calc 1 and 2

[@arkochatterjee8686]

Sir , We consider capacitors as lumped elements right but they do store charge , while the dimensions are still very small as compared to the wavelength . Sir can you please explain how are we considering it as a lumped element . thank you

[@AliHajimiriChannel]

Being lumped has nothing to do with storing energy. It is about the time it takes for the signal to propagate through it, compared to the period of the signal(s) of interest. Said more traditionally, it is the dimensions of the elements should be much smaller than the wavelength. Please watch the lecture again.

[@danielfelixsilva2002]

Great vídeo, friend do you have more classes , for all The subjects , in eletrical engineering ?

[@user-zj8xt8es1n]

I found this video searching for a flux capacitor, and I am happy to say I found it.

[@rahulbharadwaj7923]

What is the basic physics or math required for this course?

[@hamdysherif7601]

Can you please recommend me a good source to understand electromagnetics?

[@saeedyousefi3325]

Hey dude try behzad razavi's lecture videos another Iranian professor

[@youssefradwan1959]

please may i have book or reference of this doctor ?

[@michalbotor]

wait, so engineers designing a modern processor cannot use lumped model of electrical circuits (resistors, capacitors, inductors, etc.) then? mine processor: amd ryzen 7 3700x operates at 3.6 [ghz] = 3.6 * 10^9 [hz=1/s]. plugging it into the l = c / f formula i get l = (3 * 10^10 [cm/s]) / (3.6 * 10^9 [1/s]) = 8.(3) [cm] or about 3.3 [in] or is it precisely why processors tend to stay relatively small in size?

[@AliHajimiriChannel]

What you said is generally true, but there are a lot more nuance to it. Very briefly, the stated clock frequency of a modern microprocessor is not necessarily the clock rate of the data across its external connections. It is the maximum clock rate that the local internal processing units or cores are operating at. These cores are much smaller than the whole processor, where a lot of its area is dedicated to on-board fast memory. These cores are still smaller than the wavelength. Nonetheless, the data communication across a processor is not necessarily lumped and that is why they have been using controlled impedance transmission lines for some of the critical paths for many years.

[@JosipIvankovic-vq2hi]

I am deaf person, subtitle doesn't work after 2:22min. Could you add new subtitle after 2:22 ?

[@ben3673]

screw those few people that hit the dislike, they are just mad they can't be electrical engineers.

[@samuelokon8842]

Very nice Course

[@maazahmedansari4334]

How conservation of charge comes from conservation of phase? Please explain

[@osmankhalil339]

I do self study electronics.. what is the path I should follow to learn it? what is the first course? next? last?

[@AliHajimiriChannel]

If the math and physics background is there, this course would be the first EE course to take. You must take courses, on device physics, circuits, signals and systems, communications, electronics, control theory, stochastic processes, EM, antennas and propagation as a minimum and build upon those depending on your specializations.

[@MohitKumar-nd2tz]

@@AliHajimiriChannel Sir Do you have any good recommendations for stochastic process (book or course or any material)?

[@Mirsab]

If I do physics and maths a level, should I be able to understand this?

[@hergunebirsiir2004]

of course you can

[@abhisheksingh4423]

Thanks sir From india 🙏👍

[@tabluchakraborty7319]

Sir please provide lectures of full syllabus of electrical engineering through videos if possible

[@theencryptedpartition4633]

15:37, is he okay?

[@PCBAfrica]

Great ☺️

[@rogerbear3690]

deep

[@shehabmohamedhosnimohameda96]

Great

[@abdelrhman562]

what book use in this course?

[@AliHajimiriChannel]

We use most of "Linear Circuit Analysis" by Artice Davis for about 70% of the course. The remaining 30% is based on the class material and no current textbook.

[@tejaskausal6277]

@@AliHajimiriChannel Sir, can you suggest some other book?

[@sandeepchinthala200]

Hajmiri is lub

[@davidv4682]

Is this circuits for beginners?

[@AliHajimiriChannel]

This is the first course in EE for Sophomores at Caltech. It assumes you know sufficient level of background math and physics.

[@tensorbundle]

A brilliant professor and excellent lecture. Some of the applications of Maxwell's equation and electrical engineering can be linked with antenna design. Undergrad students may check out my channel to see how electrical engineers transform these Maxwell's equations into tangible electrical systems such as antenna.

[@aibasei3254]

is it for bachelors ?

[@AliHajimiriChannel]

This is a required class for EE sophomores (2nd year undergraduates) at Caltech.

[@aibasei3254]

@@AliHajimiriChannel thanks a lot. It was my dream to be a student in caltech. Hope u will soon upload new videos.

[@shambukarishivacharan9439]

at 14:00 sir is saying pushpa

[@jessedylan6162]

I was lost after he wrote down Maxwell's Equation.

[@nnfuad]

16:48

[@kirchofffontaine6845]

Subtitle Pls

[@AliHajimiriChannel]

?! It has subtitles. Hit CC

[@AlReyanLone]

the depth here is drowning me

[@erfantaheri1816]

ddsh hal kardam esmeto didam

[@rajeshsahoo9398]

I wish I could be your offline student

[@birkul5837]

it would be great if it had subtitles...

[@AliHajimiriChannel]

These is auto cc and translator in most of these lectures.

[@SUZAKU__007]

My prof would put a ppt and read from it. lol

[@barsavan449]

students are not well studied l guess :D