Razavi Electronics 1, Lec 16, Large-Signal & Small-Signal Operation

[@shubhammujumdar9270]

The 6 dislikes are all probably from EDC teachers whose lectures we've skipped to watch these videos.

[@anushazehra8183]

00:51 Developing a circuit model for the bipolar transistor 04:29 Transconductance measures the strength of a bipolar device in translating a voltage change to a current change 10:19 Transistor can act as a current source and its values can change. 13:47 Finding IC as a function of time 19:59 Dependent current source placement in simplest bipolar transistor model 22:21 Modeling the base current using a diode 28:04 Transistor model replacement and circuit simplification 31:10 Analyzing large-signal and small-signal operation of Razavi Electronics 37:26 Nonlinear functions require mathematical labor in bipolar transistor circuits. 40:27 Analysis of voltage and current in the circuit with a sinusoidal microphone signal 47:45 Large signal operation allows for signals of any amplitude, leading to complex exponential expressions for IC. 50:57 Small-signal operation assumes input signal is small compared to the bias voltage. 57:35 Small signal operation leads to sinusoidal behavior of collector current. 1:00:42 GM times input voltage equals current fluctuation

[@yasserel-azab7033]

your videos are the electronics' reference to all Cairo university students in Egypt many thanks to you prof. you deserve more than some easy words !

[@amritanshusinha8646]

Dude correct your statement , "to the world" Love from , India

[@mr.ANIMAT0N]

Greetings from Egypt. Razavi is the iconic masterpiece of electronics to us دكاترتنا زومبيز جنبه والله

[@tinotendamarufu4470]

my lecturer tells us to watch Dr Razavi s lectures lol. You are a genius, you explain so well

[@Peter_1986]

It is funny how amplifier circuit models look really scary in the beginning, but then after you have been working with them for a while they suddenly start to look incredibly simple.

[@phanindrareddyinakollu9310]

I believe this is the best explanation and interpretation of electronics circuits. Thank you so much sir for this valuable knowledge you have provided.

[@intelligentdonkey6982]

This kind of detailed observation is beyond my imagination , thanks for broadening our mind..❤️❤️

[@anthonysavage1]

You lectures are a work of art---sheer beauty and a delight to behold.

[@mostafasaber4491]

the king of electronics your student from Egypt :D

[@shujasohail4401]

Sir I can`t tell how much thankful I am to you .Such Excellent Lectures .So nice of you

[@_Mohammad_Muzamil_Bhat]

never seen anyone like him!

[@veerappanplays2254]

you are a saviour sir. Our professor either knows nothing or isn't willing to teach us.

[@shivaniits]

These lectures are beyond amazing , I am only able to understand analog electronics thank to you Professor Razavi 🙏🏼

[@mr.ANIMAT0N]

ICONIC LEGEND! TRULY A MASTERPIECE

[@carlosgarzon9896]

You were born to teach :)

[@viratcheruku]

Thank You Dr Razavi. Please keep making such videos

[@yaswanthvasu877]

You are best best best teacher in my career i have ever seen

[@kolmikael8823]

You really deserve a word of PROFESSOR!

[@Ser3naaaa]

The last two minutes of the lecture are GOLDEN!!!

[@Pulsonar]

Last 2 minutes? The whole lecture series is Golden!

[@Anointed4Him]

You make it easy as V=IR! Thanks you so much from Canada! It would be great if you do the same for electronics 2!

[@EslamMohamedX]

ur way of explanation is too good to be true :D

[@gopikrishnanm5310]

oh god, this man is making my life easier. thanks, sir for such a wonderful explanation .

[@muhammadalitehseen7181]

Thank you soo soo soo much.... You are fantastic Best teacher...!!!

[@zarthustramehr8698]

You>>>>>>>>> my prof.

[@boraozturk3634]

i am lovin the "mike"s

[@ashikjayamon3963]

I can't hope to imagine the life of those people who actually disliked this video. It must be really fucked up.

[@klaotische5701]

At 1:03:02, why (Ic0/Vt) can be equal to gm, isn't gm = Ic0/V0? since Vt = 26mA @300K. ok i probably get it. gm = dIc / dVbe = dIc0 / dV0, which means the equation isn't derived from the previous one, it is a new way of expressing it.

[@Itsmeaboud]

Gretting from jordan

[@az-op8oc]

Best lecture ,, tq Very much sir

[@mnada72]

Beside that this and other lectures are totally awesome 👌 my question: is the model developed in this lecture the large signal model ?

[@kristitopollai6948]

praise papa razavi

[@chaitanyakumarkesana9218]

please upload electronics 2 videos plzzzzz plzzzzzzzz

[@coolwinder]

Can you post the link if you find them :)

[@KrishnaDN]

fantastic.....:)

[@thanoskaraiskos]

What does that last Id represent?

[@Peter_1986]

I think he accidentally wrote the drain current for a MOSFET transistor, which is analogous to the collector current for a BJT transistor.

[@Ben-sx5xb]

37:00 the equation doesnt work

[@Pemmanator]

Me too, I have been trying it🤔

[@aanur6151]

can't we solve the equation in 34:00 with calculator? actually i guess we can and i solved it and found Ic=0,019A where is my mistake?

[@1412dante]

why the intro been change?

[@raghuveersinghrawat2]

nice

[@aayushneupane5211]

why not replacing base emitter terminal by current source? it also looks like it behaves as voltage controlled current source

[@Singh-Rajveer]

Because If we replace that by current source, Voltage across that would be Vbe and if we change Vbe , then current also...so it would not be a current source....Collector emitter junction has Vce voltage....and by changing that voltage , Ic is constant thats why that is Voltage controlled current source...base emitter junction is not current source.

[@user-mj3ef]

Are there lecture notes of the course?

[@manvigupta8719]

Can someone help me out wd the steps 57:10 how we can write exp vmsinwt by vt as (1+exp vmsinwt/vt)

[@ДенисСами]

Same problem here. I think that it need to be calculated as same except Vt in the breckets because we are taking that Vt out of breckets. Please someone give a explanation for that step.

[@raghavendrab5395]

Here, we have followed a simple rule to deconstruct the exp term that is present in the equation. We have (e^epsilon ==> 1+epsilon if epsilon

[@abrahamkennedy3016]

Raghavendra B is right, Razavi himself wrote that basic approximation on the board just one line above {i.e.: exp(ϵ) = 1+ϵ if ϵ

[@russellteejaymolina6736]

e^x = x+1 will hold if x is much much smaller than 1, say x=0.1, using your caculator is approximately 1.1(1+0.1something something), try also x=. 2,.3, etc.. and notice that as you approach 1 that expression will no longer hold. For small swing razavi considered vm to be small as compare to vt to produced a linear output, and that will hold only for small input signal because in the graph of Ic vs Vbe which is exponential by nature, you can still find a straigh line if you consider a small part of which will correspond to gm as slope of that small part of the curve, hope that will help.

[@RamaKrishna-oq4tw]

This is because.. Exp(x)=1 + x + x²/2! + x³/3! + ..... So when x

[@ADITYAAGARWAL-o7y]

the goddddd!!!!!!!!!!!!

[@user-mj3ef]

39:41 That is not Vce.

[@MinhLe-ho6fj]

What is the intro music plz ?

[@shahnazmrs3529]

Over a long time I have been thinking that BJT is a current controlled device, and now this man says it to be voltage controlled. How come everybody modifies electronics as they like?

[@Upgradezz]

Maybe looking at the credentials of the one claiming might help

[@kiromaisus]

It really depends wether you are ok if it's linear or not. If it's a current controlled device, then you just have the relation Ic=B*Ib. If you say its a voltage controlled device, then you have that non-linear function. In the end, even the beta isn't constant with magnitude of the currents or temperature. So the system is non-linear and thermically dependent. The good thing is that there are techniques to tie things, so you get an amplifier which is almost beta independent.

[@harsh9874]

✅

[@Upgradezz]

Brilliance on steroids!!

[@appatheskybison3016]

not long kong it was hong kong

[@appatheskybison3016]

hahahhahahah

[@kolmikael8823]

You really deserve a word of PROFESSOR!