Monday, December 31, 2018

⏩DRDO IRDE(Instruments Research and Development Establishment),Dehradoon.

Interview Date:16th Sept 2018.(JRF).

   This is the lab where I got selected as JRF.

Though this is my success story, you can learn from my first Interview where I made so many mistakes.Because , once Dr. A.P.J. Abdul Kalam said ," Read failure stories ,not the success stories you can learn from them".

  For this first of all they put one exam. Scheduled on 10 o clock. after the exam interview was there for selected candidates only. Exam timing was of two hours. 

   My train arrived late at Dehradoon station. I was totally new in that city. To find out the laboratory it takes time and I was 40-43 minutes late for the exam. when I went to the center, they refused to allow me for the exam. I was requesting them "I came here all the way from Maharashtra. And the train was late ." Meanwhile, an elder person said, "okay, hurry up just sit for the exam. rapidly fill the form first. But you will not get extra time".it took around 5 minutes. Totally I was 50 min late for the exam.
   There were 10 questions common for all branches and next 50 questions were of particular branches. There was no negative marking so I solved all questions very fastly. All the questions I felt easy maybe because this time I was fully prepared. Around 250 candidates were there for the exam and vacancies were 5.
In the afternoon 3 o clock they displayed the result, My name in the list was 11th.
   I had taken a MADE EASY handbook for the revision of concept along with me. I suggest you that book for the concepts. For rapid preparation. 
   On the next day morning interview was there. I made one friend there named Krishna(Himachal Pradesh). We both seek for residence. There were two Dharamshala which were cheap. Because it was a tourist place hotel prices were not affordable for me. But in dharmshala no vacancies. One autowala helped us to find out one cheap but good in condition room. We both studied in the night, asked questions to each other.
    In the interview...
   As I entered in interview hall. That person who allowed me for the exam was chief of the interview panel. He identified me, "you,    are the one who was late for exam right?".. I said "yes".
"Still you got qualified." ...good.
   Then he told to other panel members about that. Exam takers were different people and interview panel members were different only that chief was common.
   One of panel member said, "impressive...!!!"
       I think half the battle I won here itself.
 They started questioning.

1. Tell me your favourite subjects.

EDC,Digital ,controls.

2. Types of ADC?

This was my weak part in digital. I murmured," slope...something... something...".
  One lady panel member was encouraging me. "Yes, you r right go ahead".
 I had not read about this last night but I knew the names I could not remember there.

3. What is quantization noise?

   I said "no".

4. Can you draw BJT symbol?

I thought now they are making fun of me. I politely drew the symbol.

5.If you put two diodes attached, will it act as BJT and why?

I knew the answer. Its as it is given in ACE academy notes. 

6. What are the applications of BJT? 

  Amplifier, switch.

7. What are the universal gates?

The favorite question of DRDO scientists.
"Nand, Nor".

8. Can you draw universal gates using other gates?


9. By using which law?

De Morgan's law.

10. What is the zener diode?

I said,"It is connected in reverse bias.
It works on tunneling effect.
Used as a voltage regulator."

11. What is phototransistor?

I replied, "It works on photoconductive effect. When light falls on it. Current flows."

12. What is a relay?

It is a isolator ,used to connect low vtg ckt to high vtg ckt.

13. Tell me the working of wifi.


14. Types of modulation?

I told.

15. Which is efficient ASK,PSK,FSK ?


16. You have to creat a square wave what you will do?

Actually they were expecting ring oscillator. But i told "by giving sine wave as input to comparator" 
I could ans this que becoz i came across such a numerical in previous year GATE

17.What is CFL?

I confused. I murmured,"".

18. Tell me about CRT ?

I could tell them only full form. Cathod ray tube.

19. They given one graph to find the equation of it.

I derived the equation but i dont know it was correct or wrong ,they also haven't commented on it.

20. Then they asked me about my family background. Residence.....

Finally said", can you join if we select you?
The mad only will say no.
Then they said thank you. And told me to tell outside that dont send next candidate for 2 minutes.
  Here only i came to know that im selected.
While leaving room i said,"maam  I know that ADC types".
   She,"then tell me".
"But as of now I couldn't remember".
She said "okey no problem. Best luck."
 After few days admin officer called me and said im selected............


Saturday, December 29, 2018

⏩DRDO CVRDE ( Combat Vehicle Research and Development Establishment), Chennai.

Interview Date: 30th Sept 2018. (JRF).
 First of all, they have taken an exam, around 500 people were applied for the JRF post for a total of 14 vacancies of all three branches i.e. ECE, MECH, E&E.
  It was a tough exam because we have to solve 40 questions in 30 minutes all were logical and GATE level questions(neg marking). I could solve only 22. I was not sure that I will crack the exam. We were asked to wait for one hour in auditorium hall showing videos of ARJUN TANK and Indian AIR FORCE skills. After one and half hour they displayed the result on the projector. I literally bounced in the chair by seeing my name on the screen.
   They selected a total of 75 people for interview 25 out of them were of ECE branch. 
Interview started. It was the panel of 5 members.

1. What is the frequency range of A.M.?

Actually, I haven't got in which perspective he wanted to ask, I was not confident with the answer still I guessed "10 kHz". 
I suggest you don't do this mistake.
He again asked are you sure, I said yes.

2. What is the use of optocoupler?

I said," to connect the ckt optically but not electrically i.e. electrically isolated and optically connected.

3. What is the use of relay?

" Used to connect two ckts, high voltage, and low voltage. It's working is also same as optocoupler an isolator.

4. What are your fav subjects?

EDC, digital, controls.

5. Tell me the use of bypass capacitor?

I told EDC but they started asking questions of analog, unfortunately, I was not prepared with analog. I told the general use of capacitor i.e. allows ac blocks dc. According to me, I was correct because wherever you connect capacitor it does it's work. But they were not satisfied with answers.

6. Draw buffer using Opamp?

I drew.

7. Draw Ex-or gate truth table?

I drew.

8. Given one mux problem and asked to find o/p.

I drew correctly.

9. What is the breakdown voltage of germanium and silicon diode?

"0.72 for germanium and 1.21 for silicon". I was wrong bcoz they asked me breakdown vtg but I told energy band gap.

If you give 2-3 answers wrong they will say thank you automatically, you have to walk out. Same happened to me.

Check notification


Friday, December 28, 2018

⏩BARC (Bhabha Atomic Research Center), Mumbai.

Interview Date: 9th July 2009. 
DAE➝ Graduate fellowship scheme for engineering graduates.

One of my friends is sharing the experience.
   I was the first person to be interviewed and was quite nervous. When I entered in the interview room the panel members (5) greeted me warmly.
   One of them asked me to hand over my marksheets so that he could have a look and also took the project report I was carrying. After the initial inquiries...Background, how was the written test etc. Then asked me to write down five subjects of my interest.

One of the members started with Analog.
1. Draw a basic CE amplifier.
2.function of all the capacitors i.e. coupling bypass.
3. Explain how you can say emitter terminal is common whereas Re is connected.
4. What is the gain of this amplifier?
5. Why potential divider biasing?
6. What is Q point?
7. Draw the load line, explain it's characteristics
8. How do you get various regions.?

Then they proceeded to Opamps and spent a lot of time on it.
1. Asked to draw a basic Opamp amplifier.
2. What is it's gain ...Derive it.
3. What is a virtual ground?
4. Can you prove that both are at the same potential? 

One of the members given a problem on Opamp and asked to draw output...Gain and input were given...

One more on CMRR concept. Then proceeded to Precision Rectifier. I got stuck here while drawing the ckt. Got some hints but I realized that made some mistake s.

They moved to Diode...All the basics of the diode ...One question on the resistance of the diode.

In Digital ...Asked to design a counter, so many questions regarding counter. Asked about ADC and DAC.

The interviewers are very helpful in nature, provide so many hints, they will literally get you to the answers. I got nervous after 50 minutes in the interview and was offered tea and water. Any way...Towards the end ...Last half an hour... Questions focused on project and power electronics. I felt I had done better in this half an hour. Was actually feeling quite bad when I couldn't by hi Dr. Because questions were so logical and valid.

After the interview, I asked to sit outside for five minutes. I was stuffing all my mark sheets and was preparing to leave. A ma'am came and given me the medical slip... I was on the seventh heaven... I got selected...


⏩BARC (Bhabha Atomic Research Center), Mumbai.

   This is an interview of a candidate who is selected as a scientist in BARC. His name is Abdullah Abdurrehmaan. He got medical slip i.e. got selected. Out of 66 people, 5 were selected that day. A BARC scientist candidates interview lasts for at least 1 to 1:30 hours though you know anything or don't know. They politely but completely examine you.
   Let's hear in his own words.

   I have two years of experience in R&D they asked me related to that and argued for around 15 min.
  Then they asked my five favorite subjects. 

1. Op-amp .
2. Digital .
3. Electronics devices and circuits.
4. VLSI.
5. Communication.
   They started with some simple ckt but then they kept asking till I require some hints.
 Then they started again with 
Drawbacks of a simple integrator.
Practical integrator.
What if a constant current is used.
Draw frequency response.
Pole-zero plot.
Given some input and asked to draw the output.

  Then they gave me some pulse then asked me to design a digital ckt to expand it 10 times then they asked alternate methods and lots of counter questions.

   Then on transistors, all configurations of CE amplifier s. 
Effect of resistance Re on the gain, stability, frequency etc.

   Then on specification sheet of BJT, for such parameter what condition comes in to picture. They questions on the gain-bandwidth product for 15 minutes.
   Then they asked me to draw 3 integrators connected in a loop ( i could recognize it as RING OSCILLATOR). 
The output of ckt frequency, drawbacks, and uses.

 Then they asked about oxidation processes and what if we want more oxide layer.

Some indirect questions on the advantages of modulation, wired and wireless communication.

   Few of them highly impressed and they appreciated that I remember a lot of things even after two years, I told them that I used to help juniors to solve their doubts.

For the questions which I was not confident, Simply confessed that I haven't come across and I have no idea about it. So be honest and do comment if it goes out of reach but no silly answers and stick to the basics.


⏩DRDO ARDE(Armaments Research and Development Establishment),Pune.

Interview Date: 23rd Aug 2018. (JRF).

   One of the best, well-equipped lab. There was an exam before an interview. Total 67 people appeared for an exam from ECE. They selected 15 candidates for interview, in that my number was 5. Here most of the questions asked were application based. 7 scientists were there in the panel. Biggest panel I had been seen till now.

   1. Do you know, what is hydraulic and pneumatic?

I said" yes, hydraulic uses water and pneumatics uses air.

2. What is the main advantage of hydraulic over pneumatic?

I was well known about the pneumatic and hydraulic because of my final year project. Hydraulic can be used to lift a heavy load and it is slow whereas pneumatic is faster but can not be used for a heavy load.

3. What is RFID? 

"Radio Frequency Identification".

4.what will be the range and frequency of RFID?

"Sorry sir, I don't know."

5. Tell me the difference between microcontroller and microprocessor.

I was aware of the answer to this question but due to stress, I could not answer well. I could tell only one difference i.e. system on chip and system in a chip.

6. I have to retain lower bit as it is, what should I do? 

This was a logical question. I was thinking in which context she is asking. I had taken around 3-4 minutes hence they moved further.
Now my confidence level became low. I suggest you don't stumble while giving the answers, be confident though you are not able to give the answers.

7. In what direction CD/DVD rotates in CD/DVD player?

This was a bouncer for me. I replied, " I don't know".

8. Okay, then do you know how the decoding process takes place in that player? 

I was blank this time. "No...!!".

9. What is the difference between BJT and MOSFET? 

I answered," BJT is bipolar, MOSFET is unipolar. BJT has low input and high output impedance. MOSFET has high input and low output impedance.
 This is also one of the favorite questions of DRDO scientists.

10. Do you know, Which type of antenna is used for TV nowadays?

"Yes, it is parabolic antenna".

11. What is the gain of that antenna?

" One formula is there". Actually, I was trying to remember the formula.

12. What is that formula?

" I know, but I can't remember it now..!!"

13. Okay, thank you. 

Hushhhhh....!!! , This was the toughest interview for me. Checkout my Easiest Interview.
Unfortunately,  I was not selected.


Thursday, December 27, 2018

⏩DRDO DEBEL(Defence Bioengineering & Electrochemical Laboratory), Bangalore.

Interview Date: 20th Aug 2018. (JRF)

   There were around 75 candidates applied for the JRF post and vacancies were only one.
   So they took one exam in which 30 questions asked for half an hour. Most of the questions were previous year gate itself and some numerical aptitude questions but they were also from previous year gate. I was familiar with the questions hence it was not a big deal to clear the exam.
   One hour gap was given to declare the result. I was sure, my name will be on the list. They selected 15 candidates in which 12 were MTECH qualified and three, considering me were BTECH+GATE. Why I'm mentioning it you will come to know later. The selected candidates asked to sit in auditorium hall there we got a chance to interact with each other.
   One of BTECH+GATE had selected for the interview of ISRO scientist but got rejected in an interview. I remember his name, Peddy Reddy. Another one has GATE rank of around 2700, his surname was Malhotra.
   I was second last according to the list, I would like to mention that the list for the interview is not according to the marks obtained in the test but according to the application number.

1. What is your aim?

I said," I want a govt job.

2. Why govt only?

Because there is no fear of getting fired i.e. job security.
  The chief of interviewer laughed and said to me," who said you that, govt is also changing policies now. Remove that thought from your mind". One type of humerous atmosphere created...I replied him with a smile, "okay, sir I will".

3. Do you know diode?

Observe how the sequence of questions asked. I said, "yes".

4. What is peak inverse voltage of the diode?

When diode is reverse biased, maximum value of reverse voltage occurs at the peak of input cycle.

5. The condition to convert Fourier Transform to Laplace transform.

I answered," when sigma equal to zero."

6. Application of Fourier Transform?

I said, "to convert time domain to frequency domain and vice versa."

7. What is the purpose of doing transform?

I answered," to analyze the signal well."

8. Explain Wavelet transform.

I confessed that I don't know, again he asked some more unknown transforms, my answers were no for them.
I said, "I know only Fourier, Laplace and z transforms.

9. Tell me what are universal gates and why they are called universal?

This is also a favorite question of DRDO scientists.i is a simple question.

10. What is counter and it's application?

I said it is a sequential ckt made up of flipflops and used to count the pulses.

11. Any other applications?

"Frequency division."

12. Do you know C language?


13. Write a program to add two numbers.

I wrote.

14. Have you studied communication system and what in that?

"Yes, satellite communication,radar...
But I'm not comfortable with the communication system.

15. What is ECG?


16. What is difference between graph and gram ?

"I know only graph that is graphical representation". 
I don't know this was the correct answer for the question but they stopped here.

17. Can you shift yourself from Maharashtra to Banglore?

The pleasant moment,that gives hope to be selected."yes".

But afterwards i came to know that last candidate Malhotra and peddy reddy got selected. 


Wednesday, December 26, 2018

⏩DRDO ITM (Institute Of Technology Management), Mussoorie.

    JRF Interview Date: 13th Aug 2018, Application Date: 5th May 2018
   It was a very interesting interview I faced and the location i.e .mussoorie, you just imagine heaven.
   The  Interview call letter from ITM explained, "you have to bring one ppt of 5 slides on the subject 

  1) What are your expectations as a JRF?

  2) How will you contribute ITM?

 And it was mentioned that there will be P.I.
After ppt presentation.
   I was totally astonished by seeing the beauty of nature there, from the mess, you can imagine yourself in a five-star hotel.
   Interview started, it was a panel of 6 people.
I was asked to sit in the chair middle of the panel .

1. How are you ?

Fine, thank you, sir.

2. How you are feeling now?

They were trying to make me comfortable, I guess. I replied, "cool". Atmosphere is so cool there that they use the heater as we use fans.

3. Do you work anywhere?

No, I am fresher.

4. Your application form shows you are pass out of 2016, then what you have done two years ?

I said," searching for the govt job and preparing for the gate.

5.Okey, well. Have you brought PPT along with you?

Actually, ppt were submitted at the gate itself,bec because in any DRDO premises no electronic gadgets are allowed.

   This was the ppt i presented.

PPT presentation time was of 5 minutes only, 5 slides in 5 minutes. They were very much impressed by my ppt making. They appreciated it. And asked, "which software is used". I said, "no any software, just MS POWERPOINT.
 This question was very pleasant for me

6. Would you like to join ITM? 

I said ", sure sir....!!!".

Though it is a DRDO lab, it is totally non-technical. The candidates selected as scientist used to get trained there. Even directors of other DRDO labs also called there for training.

  I was the 5th candidate to be interviewed there, still 51 candidates remaining. May be 6 people among them presented well and got placed , unexpectedly i was not selected....

   This is vacancy notification.


Tuesday, December 25, 2018

⏩DRDO SAG( Scientific Analysis Group)

Interview Date: 2nd Aug 2018. (JRF).


There were 5 scientists in the interview panel. Three gents and two ladies.

1.what is a stable system?

I answered," for every bounded input there is bounded output is a stable system."

2. Write the expression and draw a stable signal?

I wrote the expression and drawn the sine wave as a stable signal.

3.state the difference between causal system and causal signal.

For Causal system, there is no output for future input i.e. nonanticipative and causal signal is zero for t<0.

4.write truth table of Ex-or gate.

I drew the truth table.

5. Which are the Universal gates?

Nand and nor.

6. Draw not gate using nand and nor .


7. Tell me the difference between latch and flip-flop? 

This is one of the favorite questions of DRDO scientist's. At that time I didn't know the answer so I confessed.

8.Draw inverter using Ex-or gate.

I drew.

I had given all the answers correct except one. I thought my selection is fixed but why they rejected I don't know.


Monday, December 24, 2018

⏩DRDO NSTL(Naval Science &Technological Laboratory  ),


interview date:5th July 2018 (JRF).


      This lab is situated in Goa on sea beach in Vasco-da-Gama city.pleasant an atmosphere.
There they have taken one exam of 40 marks and time gave was one hour.there were 37 candidates for the exam and the vacancies were only 2. They called according to the list of 15 selected candidates. I was one of them. one girl holding 1st no. and I was second. Interview started.....!!!

      1. How you are feeling?

Great...!!! Actually pretty good.

       2.what do you know about this lab?

Generally, anybody attending the interview must read the information regarding the institute or had i.B ut on google search I came across NSTL Visakhapatnam only. So I read it and answered as its a lab which makes torpedoes and naval related staff.
   I was wrong...!!! Actually, it was range technology lab.sister of vizak NSTL. They corrected me.


       3.Tell me about your B-tech project.

    As I started to explain about my project i.e. Hydraulic Robotic arm controlled by human arm they interrupted me by asking several questions regarding my project so hence I could not explain well. It was negative impression on them.
Suddenly one of young scientist asked 

   4.What is open loop and closed loop system?

  But ...The senior one sitted in middle .Said "thank you".
I was sure ...Not selected.
It is my heartly suggestion to you is prepare well your major project and present it well too.Because it's not important to have knowledge without a good expression.


⏩DRDO CFEES (Center for Fire, Explosive and Environment Safety), New Delhi.

Interview Date:12th June 2018.


     This was my first interview in DRDO. I attended this interview as a trial. Just to know what type of questions are going to be asked and to understand the depth of the questions. I observed that the panel was of 5 people all were around 40-45 age group. First of all, they asked me "where are you from ?" I told them that I'm from Maharashtra. They got astonished. Surprisingly asked me about the time required to travel. Then they moved toward technical questions.

   1. Do you know photocell?

Actually, I didn't know what exactly mean by photocell at that time. Even though I just tried to guess ...I told them that photocell is like a solar cell when light fall's on it. It gets charged.
  Suddenly one of the aged interviewers got angry and said, " don't tell anything like an illiterate person". Then himself explained that photocell is a device which can be used to measure the detonation time of an explosive. we, human, cannot test the detonation by actual such a device helps us.
  After the interview, it was my strategy to analyze the questions asked and search the answers from Google.
I found that photocell also called as LDR(light dependent resistor) or photoresistor. It allows the flow of current when light falls on it. Generally, LDR's are made up of selenium, cadmium.

2.What is the use of impedance matching?

I answered, "it is used to transfer maximum current to the load."

     3. Tell me what is maximum power transfer theorem?

This was a counter question for the previous answer. but I explained MPTT.
Now they asked my favorite subjects during the degree.
I told Electronic devices, Digital electronics, Control systems, Network theory.

      4.Nortans and Thevenin Theorem?

I explained thoroughly but they tried to confuse me.

      5.DTL, TTL Logic families?

Unfortunately and unconsciously I uttered it is not in the syllabus of GATE. They were shocked, looking at each other "it was there in degree syllabus or not?  !!"
I nodded "yes, it was but haven't studied it well".
I would like to suggest you, don't answer them if you don't know. Just agree that you don't know without justification.

     6. What are the advantages of negative feedback?

I couldn't answer it well though I know the answer well the pressure created by the previous incident stumbled words.....
Then they said thank you. Simply understand that it's time to leave.
I was the second last candidate and it was around 1:30 pm.