Project Engineer Interview Questions
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Q2: A pnp transistor with its base connected to a voltage source, the V source is connected to a +10V source. The emitter of the transistor is connected to a resistance, and then to the same +10V source. The collector side is connected to a capacitor, which is not charged at t=0-. Given the graph of Vsource = 10 V stepping up at t = 0 to further, draw the graph of Vout. Vout is between the point of collector and capacitor.
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I just made it back from Lutron's HQ and I was asked for the same question. My first approach will be identifying a PNP BJT, and elaborating all 4 BJT operating regions. Before t = 0, since q = 0, by using Q = CV, we can tell that the voltage across the capacitor is 0. Hence, Vo = -10V before t = 0. Recall the capacitor's current equation: I = C*(dv/dt), we can solve for the slope of changing voltage -> dv/dt = I/C. Here, I is simply the BJT's collector current, which can be found by looking at the BJT's emitter current. Given that the (beta) parameter is infinite, we see the base current to be 0. Now, at this point, we need to look for I_E. Since the R is given to be 9.3k, and VEE = 10V, it is natural to assume V_EB = 0.7V, and thus the voltage across R = 9.3V. Therefore, I_E = 9.3/9300 = 1mA. Voila, we now values for all currents: I_E = I_C = 1mA, and I_B = 0A. Plug the I_C value into the equation: I_C/C = dv/dt (C = 1uF). We know that the slope of the voltage change is 1000V/second, or 1 Volt per millisecond. Now, we know the capacitor voltage raises at 1V/ms from -10V, but we also need to know where is the upper limit. Looking back to the BJT basics about operating regions and BJT's 2-diode model, it is not hard to identify that this PNP BJT must operate in "Saturation" region (NOT IN "ACTIVE" REGION!). The boundary of that region is V_BC <= 0.7V (I hope everybody is able to solve for this). Hence, 0.7V will be the upper limit for capacitor voltage. At this point, you will have a flat line at Vo = -10V before t = 0. and raises at 1V/ms for 10.7ms and hit Vo = 0.7V. From t = 10.7ms and on, the Vo stays at 0.7V. Less
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ANS: Vout should be constantly -10V until t=0, and will hit V=0 V linearly from V=-10 V after t=0. Less
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Hi, Can you explain why it linearly increases? Are you assuming that Collector is tied to -10V? The pnp transistor is completely cutoff for the given biasing. The only way the capacitor is going to charge is through leakage currents. It is very slow and takes a lot of time. Please advise me if my analysis is correct. Less
Asked questions about injection molding part, any sensor technology used in previous job.
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SUMMARY OF QUALIFICATIONS 40+ years experiences as Senior Civil Engineer worked on projects in land development, water, sewer, grading, hydrology, CPM schedules, drainage, transportation systems, geotechnical, seismic retrofits, structural designs & construction as Senior Project Construction Manager, Structure Representative, Project Design Engineer, Resident Engineer, Chief Inspector Sr. VP for various horizontal/vertical Public Works & Private projects, Partnership, P3, staffing & reviews (Projs. Cost $4+ billion). EDUCATION B.S. Civil Engineering- Florida International University (FIU) (Florida State, Miami, FL), Miami, FL 1979 Less
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40+ years experiences as Senior Civil Engineer worked on projects in land development, water, sewer, grading, hydrology, CPM schedules, drainage, transportation systems, geotechnical, seismic retrofits, structural designs & construction as Senior Project Construction Manager, Structure Representative, Project Design Engineer, Resident Engineer, Chief Inspector Sr. VP for various horizontal/vertical Public Works & Private projects, Partnership, P3, staffing & reviews (Projs. Cost $4+ billion). EDUCATION B.S. Civil Engineering- Florida International University (FIU) (Florida State, Miami, FL), Miami, FL 1979 M.S. Environmental and Urban Systems. Also, M.S Urban Transportation. FIU, Miami, FL 1983 Wrote a master thesis on a major public works project Which saved the owner net net about $100 million present value & about 3 years by implementing the findings, redesigns, value engineerings, & recommendations. P.E. Licensed Professional Civil Engineer Registration No.: 53250, California, Current, not expired, clear. Less
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40+ years experiences as Senior Civil Engineer worked on projects in land development, water, sewer, grading, hydrology, CPM schedules, drainage, transportation systems, geotechnical, seismic retrofits, structural designs & construction as Senior Project Construction Manager, Structure Representative, Project Design Engineer, Resident Engineer, Chief Inspector Sr. VP for various horizontal/vertical Public Works & Private projects, Partnership, P3, staffing & reviews (Projs. Cost $4+ billion). EDUCATION B.S. Civil Engineering- Florida International University (FIU) (Florida State, Miami, FL), Miami, FL 1979 M.S. Environmental and Urban Systems. Also, M.S Urban Transportation. FIU, Miami, FL 1983 Wrote a master thesis on a major public works project Which saved the owner net net about $100 million present value & about 3 years by implementing the findings, redesigns, value engineerings, & recommendations. P.E. Licensed Professional Civil Engineer Registration No.: 53250, California, Current, not expired, clear. Less
Add two numbers using half adder logic.
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2c+s whr c=carry & s=sum
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2c+s whr c=carry & s=sum
They asked if you are comfortable in the working conditions.
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you will regret it sooner than later. resign before it's too late. From past employee. Less
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I have done the following Technical Experience, · Construction of Chemical Building , WareHouse Etc.. · Construction planning & scheduling · Construct Low Linkway & High Linkway · Excavation of pile & Pile cap · Earth works & Turfing · PUB Drainage Works · Sheet Piling Works · Demolition of High Rise Buildings & SubStation· C7 ,C8 & Scupper Drains Less
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good luck, you need it, sincerely
Most difficult or rather unexpected quesion was to explain how i am intrested to work with the company.
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AS IT IS A VERY WELL KNOWN COMPANY
What is database indexing?
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Don't know
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Ok
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If you have a huge amount of data in the table, and if a particular column is taking too much time to retrieve/fetch. We can apply indexing on that column for faster retrieval types of indexing 1) clustered index: faster retrieval of data 2) non clustered index: relatively slower to clustered indexing. Less
What kind of work did you do in the previous company
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Do you prefer to work alone or teamwork?
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Tested more on approach than solution. An island has a grass heap and its getting burnt, how do you stop that.
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Tried talking about how I can do that, like Use water around / Use something around to throw grass in water and probably collect later Less
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i would try hard to pour water on the island in order to stop the grass from burning. Less
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instead of water, we can use sand. Most of islands have sand beaches