IIT Hyderabad Very Interesting RC Question, Analog Interview

So here we r going to discuss a question being asked in an Interview on RC circuits.

[@sumitsarpal1193]

Let me add my two cents to it... this is a very strong second order LPF due to huge capacitors. If you calculate the pole frequencies you will get very small values, both less than 1 Hz (by putting s=jw in the T/F). The input is a periodic square wave with a fundamental frequency of 1000 Hz ie the first sinusoidal component in its Fourier series expansion will be of 1000 Hz frequency. The average value of the periodic square wave over one time period which corresponds to its dc content turns out to be 2.5 volts. Since the poles will start the rolling-off of the magnitude at frequencies as small as 1Hz, this attenuation will become huge at frequency even of the first fundamental (1000Hz). This is the reason why the voltage across capacitors is almost equal to dc content of the input. In frequency domain it's much easier to figure things out.

[@analogeasy-peasy7559]

This is the right way to feel about the circuit.

[@mohdkhairizulkalnain279]

Hi there thanks for the videos! Keep em coming! Just out of curiosity, may I know why the discharge and charging time constants are not equal initially?

[@Shivshankar-c9f]

Please keep on posting videos like this there are students like us to support from whole heart

[@trinetra-teaches]

Thanks a lot for detailed discussion. This is very helpful for analog interviews. Finding analog interview questions is very tough. Keep posting more. A good initiative.

[@analogeasy-peasy7559]

Thanks for the appreciation, was quite busy lately. But surely will be continuing the same.

[@HardwareNinja]

Hi, check us out for engineering interview related questions. We'd love to hear your feedback! kzbin.info/door/7h3PROcX7Zgx00alQokJ-w

[@AllenSA_airohaSun]

Analog interview questions is very tough

[@Shivshankar-c9f]

Please keep on posting videos like this there are students like us to support from whole heart❤

[@fantastic1046]

I knew this concept, but you really make me understand it so better

[@bhavikparekh2044]

Its basically PWM modulation on a second order LPF, if the duty cycle is 50% then answer is half of vdd which is 2.5. If you change the duty cycle, then output will change accordingly

[@ebadurrahmankhan4397]

what if the second branch is taken as first and the first one as the second? what will happen that? can you give an analysis?

[@abhisheksamboddu6580]

oh no ...i was asked the exact same question for Summer intern at TI..wish i would have seen this before:"...anyways bhiyya are u from mtech or btech?

[@poiuyt52]

Can We can solve this by nodal or mesh analysis..????

[@mandlikprajwal466]

Why you said 2.5 volt Won't there be some voltage drop in resistor itself. Your kvl will fail if this happens

[@Lol-dt1mw]

Thank you bro for such wonderful video. I saw your videos and understood new concepts. On that basis I'm able to join Texas instruments for internship as an analog intern. Thank you once again...keep uploading...keep rocking !!

[@analogeasy-peasy7559]

Wow that sounds so beautiful ❤️. Texas Instruments intern, A very bright future is waiting ahead for you. Congratulations 🥳

[@Lol-dt1mw]

@@analogeasy-peasy7559 request for you...Will you suggest me some necessary stuffs or topics or some softwares which might be useful for an analog engineer; so that I can prepare for it and work better during my internship...Any suggestion based on your experience...!? It will be great help for me 🙏

[@analogeasy-peasy7559]

Start going through basic analog lectures of Nagendra Krishnapura, that's enough

[@analogeasy-peasy7559]

One Point Actually - we can always get the time constant of the whole circuit by calculating the Transfer Function of the circuit.

[@pranjalbaishya1878]

Nice video. Sir I am not able to understand how the waveform is converging to 2.5 volts. I tried to derive from the equation but not getting the result.

[@rohanlal3695]

The Vx comes out a series of exponential considering charging minus discharging, I tried out to sum till n tendon ding towards infinity .

[@alansaldanha1698]

What happens if the input is 5V dc input? Will there be any change? Good analysis by the way.

[@getusel]

In that case the output settles at 5V

[@IcRDlayout]

Why not add two switches,one is above capacitor 1f and the other is above 10f capacitor??😊 Time is t1 and t2😊 First t1 closed and then or First t2 closed and then ....

[@pallavisingh9973]

Please.. continue these types of questions.it's my humble request

[@analogeasy-peasy7559]

Sure. After seeing such a huge request from you all guys. We feel really motivated to start it again. :)

[@HardwareNinja]

Hi Pallavi, check us out for engineering interview related questions. We'd love to hear your feedback! kzbin.info/door/7h3PROcX7Zgx00alQokJ-w

[@VipinKumar-re2cn]

It is really unique in youtube.

[@analogeasy-peasy7559]

Shukriya Bhai

[@ajaychauhan-tf4ce]

Bhai to Gazab hi kr diya..

[@shashankmourya4366]

Thats one good explanation 👍

[@HardwareNinja]

Hi Vipin, check us out for engineering interview related questions. We'd love to hear your feedback! kzbin.info/door/7h3PROcX7Zgx00alQokJ-w

[@akashwayal8797]

why 1f capacitor is charging up to 2.5v if supply is 5v?

[@analogeasy-peasy7559]

Because the input wave is on for a period T/2. It had been charged to 5v had the input voltage be a unit step in nature.

[@naveenchoudhary2675]

Guys please donot Stop..!!! can I request you guys make videos on various commonly used circuit such as buck-boost, charge pump etc.

[@analogeasy-peasy7559]

Hii Naveen, actually we guys have shifted to Bangalore like on 4 th April. We are trying to find a good flat and settle in hear. There are many new challenges to handle in the new city but surely we need to get some time and get back to what we love the most. ^_^

[@naveenchoudhary2675]

I also live in Blr, 😀 traffic boht hogya.. company k pass lena ghr

[@GregoriousApartment]

@@analogeasy-peasy7559 where do you guys work?

[@vamsisyoutube928]

Brother every one are telling RC Circuit is very important concept . Could you tell any sources for preparation of RC circuit so that we can answer in written test and interview

[@analogeasy-peasy7559]

Nagendra Krishnapura lectures are freely available on KZbin you can refer that. Also go through all the GATE EE and EC questions bank for Networks at least. Else Transient and Frequency response is what the interview goes around. :)

[@HardwareNinja]

Hi Vamsi, check us out for engineering interview related questions. We'd love to hear your feedback! kzbin.info/door/7h3PROcX7Zgx00alQokJ-w

[@thesailaja5941]

Everything is great guys why can't you start teaching❤

[@user-kz8di7nn9g]

For what purpose this interview was ?

[@HardikJain_YT]

gr888

[@Ankitsingh-my1vu]

Very confusing explanation

[@analogeasy-peasy7559]

Yep no doubt it is not easy to follow but don't lose hope keep trying.

[@nidhigupta4461]

@@analogeasy-peasy7559 why it is reaching only at 2.5V ..can you make it more clear?

[@balajin2472]

​@@nidhigupta4461i believe that 1khz square wave input is of 50% duty cycle. The RC network acts like a low pass filter and averages out the 50% duty square wave to approximately 2.5V (50% of 5V)

[@Shivshankar-c9f]

Please keep on posting videos like this there are students like us to support from whole heart

[@Shivshankar-c9f]

Please keep on posting videos like this there are students like us to support from whole heart

[@Shivshankar-c9f]

Please keep on posting videos like this there are students like us to support from whole heart