Hybrid-π Model (Solved Problem)

Analog Electronics: Hybrid-π Model (Solved Problem)
Topics Covered:
1. Steps to draw dc equivalent circuit of amplifier circuit.
2. Calculation of base current.
3. Calculation of collector current.
4. Steps to draw ac equivalent circuit.
5. Calculation of transconductance.
6. Calculation of voltage gain.
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[@__SHRAVANIPACHUNURI]

Sir In this question why don't u consider Vbe=0.7v ..?

[@omaraljedani4727]

I hope you read my comment before my exam next week. You say if you have any questions post them in the comment section. I see many questions here which were not answered by NesoAcademy. Can you please answer them? And Than you so much for the effort and great videos! a sum of most interesting questions (in my opinion) based on other people comments: 1- Anjali Jain 6 months ago While calculating Vo, how did you take the direction of current through the 3K ohm resistor as bottom to top? 2- raveena ravi 3 months ago How to find whether to use low frequency signal analysis method or to use high frequency signal analysis method? 4- Ameet Mehta 2 months ago sir can you please tell me why vbe = VT Reply: manjunath karnati 1 week ago Vbe is not = VT gm=ic/vbe gm=1/(vbe/ie). Approximate ic=ie gm=1/re Since re=VT/ic,,,,gm=ic/VT

[@94D33M]

this would have been an even more helpful channel if neso actually replied with our queries, but i can understand that if he goes on to read comments, his whole day will pass. With the questions you gave i'll try to answer with my little knowledge. 1) In the loop on the right, Ic is going down so it must exit from the right, from bottom to up. 2) I'm sure it will be told in the problem, or frequency of voltage will be given. 3) you're right, Vbe does not equai VT

[@pawanmarskole6721]

sir can you upload more solved problems of hybrid pi model

[@faizaanqureshi2659]

Zi = 101.131k (Zi = 100k + rpi) , Zo = Rc = 3k (as current source get open-circuited), Ai = 100.119 (as Ai = Av*(Zi/RL) and RL is Rc here)

[@priteshpawar9542]

Thanks sir! It was helpful

[@nityanand4581]

Small correction : units of gm is A/V rather than a/mV.. Rectifying the answer .... With sligh approximations .. the ans comea out to be 299.94 .. (The Voltage Gain) Edit- Sorry .. sir is correct Edit 2- Even found out this is a ques from Sedra Smith

[@violajb3960]

god bless u i had problems with this form of problemos

[@bijoyroychowdhuryprinon6768]

in parallel circuit tll the viltages are same across the circuit..why did you multiply with 3k while finding the output voltage..? thanks.

[@sundeepbasavaraju4466]

sir why cant we calculate input voltage by multiplying base current and r-pi

[@prescottluah6404]

Sir, i just wonder w/o the coupling/ decoupling cap. at the input, wont it 'corrupted' the AC input? i mean couldnt it all 'superimposed' AC/DC components?

[@sairamaddanki9556]

Sir, pls make videos on low frequency response of bjt amplifiers

[@anjalijain2860]

While calculating Vo, how did you take the direction of current through the 3K ohm resistor as bottom to top?

[@snehalranjan3546]

Consider the loop containing gmVbe and 3k resistance, In a loop, current can flow in one direction only, and as we consider the direction of current source as dominant(downwards ) , then subsequently the direction of current thorough 3k resistor must be upwards

[@Pr3kashSingh]

Thank u s much..

[@lakshmipriyanka4490]

Thank you sir

[@sugramalik]

sir why didnt we applied kvl from vcc down the loop?

[@demetriusdemarcusbartholom8063]

Thank you

[@umairfarooq3160]

sir .. upload lecture on ac load line with example

[@swethap7615]

I need the continues video related on small signal analysis

[@vijayvijaysaradhi8276]

sir how to calculate input conductance, feed back conductance, out put conductence

[@parthvaland7877]

thank sir

[@SekarMP]

Thanks @Neso Academy. If I solve the same problem using re model, I get voltage gain as 262.85, Can you please explain why this difference? I used formula Av = -beta(Rc)/((beta+1)re))

[@collegetv7986]

That formula is invalid here because in previous case Rb resistor was connected in parallel with voltage source(for ac model) but here it is connected in series with voltage source.

[@willysonsteward6543]

THANK SIR

[@surajbhushan3596]

sir please make videos of feedback amplifier

[@ananya5688]

Nice video

[@raveenaravi3786]

How to find whether to use low frequency signal analysis method or to use high frequency signal analysis method

[@sarvesukhinabhavantu5671]

Just use ur fcking brain

[@ayushwagh5428]

ty fam

[@hassanalmosawi822]

You can get additional examples on this method

[@daviddashti9227]

You sir, is a fucking hero! Thanks!!!!!

[@anubhav3955]

sir if my answer -2.3 v rather then 2.9 v its allso correct naa

[@ayemaeyalit3354]

Is V_BE assumed to be equal to 0.7?

[@hemantsir662]

sir can we solve above problem with the help of re model ...

[@sameerdurgoji5583]

Same doubt...

[@sandeepkumawat4982]

How the value of gm and rpi comes

[@arvindsuthar7243]

Sir....from where did u put the values of 'Vbe' & 'VT'????......is it given in the question??

[@sumitrajpal4167]

beta..tumse na ho payga btech

[@jackdanksterdawson112]

Vt value is fixed 26mv and vbe u can find by using voltage divider rule but vbe for a npn transistor is 0.7v.

[@chandraketu4455]

How to know by which method we have to solve the problem??

[@gaurav0883]

Please tell if you got to know

[@thebrokeentertainer5115]

If emitter is grounded you go for pi model if base is grounded you go for T model

[@pradyumnprakashshukla9540]

Sir pls upload videos on multistage amplifiers pls!!!

[@arunn2413]

Want videos on power amplifiers

[@mdmiraj4690]

what is transcondutance?

[@shikharsinha6407]

What does negative sign in Av means?? It's significance??

[@danielmwambogha5857]

output is inverted from input; input and output voltages are 180 degrees out of phase; input voltage drives the current into the network while output voltage also drives the current into the network

[@prajwalshete8466]

phase change of voltage by 180 degrees

[@prescottluah6404]

Inverted amplified.

[@ameetmehta7444]

sir can you please tell me why vbe = VT

[@Manjunath-tv2rx]

Vbe is not = to VT gm=ic/vbe gm=1/(vbe/ie). Approximate ic=ie gm=1/re Since re=VT/ic,,,,gm=ic/VT....

[@user-du1fy9tk8j]

VT = 26,, how it's comes?

[@allaboutdreamies7977]

What is VT?

[@vincytheman]

Can we not use (beta x Ib) instead of (gm x vi)? I did that and I got the same result 😀

[@mohammadsaifulruddinbinmoh5814]

how to get Vt

[@satyanarayanareddykarri489]

Well....we can get the approximate answer by using this formula... Av= beta*(RC/Rb) Which is equal to 3.😎

[@charanm1093]

How to get the hybrid π model from a given CE amplifier......?

[@akleshchoudhury4140]

why we are short circuiting the AC source , we need to short circuit the DC source as per the previous video. Is this a joke?

[@jainamshah1077]

Sir question can easily done by (beta*rc)/(100k+rπ)

[@saranshgupta9119]

Jugaad huh

[@debajitghosh441]

How to get V BE =0.7V Plz sir

[@Diormaz]

in forward active region we assume Vbe is equal to 0.7v

[@raymondbaring8470]

Why is there no tutorial showing how to solve for Rin AT ALL??? T_T It seems to be unknown to KZbin when most likely such question always come out in exam

[@Kavithomas_Engineer]

Hi guyzzz I'm using Av=-gm.RL Answer I'm getting is -265.2. This is valid or what's my mistake. If u know help me understand.

[@thiennguyenchi6862]

it actually is Av = -ic.RL/ib(RB+r(π) ) because in this case (Rin = Rb + rπ ) if you use -gm.RL so it's -ic/ib.(Rπ ) and you will be missed the Rb

[@souravkundu9431]

your ans is correct i think.. solving by anther methd i also gate saME ANS

[@souravkundu9431]

as Rs is not present , the value of Rb will be cncled out

[@souravkundu9431]

Av= -gmRc( Ri/ Ri+Rs). here Rs is not present so frmula remains = -gmRc

[@vishalmishra8202]

2:33 which law ?? 😆😍🤣

[@travellerhasib5522]

KVL

[@laxmanrao9622]

Not satisfied

[@UdayadityaSinghWarrior]

f