Exam_S09_01 - ECE-255 Exam I February/l 1/2009 ether treat...

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Unformatted text preview: ECE-255 Exam I February/l 1/2009 ,, ether, treat Name: (Please print clearly) Student ID: INSTRUCTIONS This is a closed book, closed notes exam. Carefully mark your multiple choice answers on the scantron form. Work on multiple choice problems and marked answers in the test booklet will not be graded. Nothing is to be on the seat beside you. When the exam ends, all writing is to stop. This is not negotiable. No writing while turning in the exam/scantron or risk an F in the exam. All students are expected to abide by the customary ethical standards of the university, i.e., your answers must reflect only your own knowledge and reasoning ability. As a reminder, at the very minimum, cheating will result in a zero on the exam and possibly an F in the course. Communicating with any of your classmates, in any language, by any means, for any reason, at any time between the official start of the exam and the official end of the exam is grounds for immediate ejection from the exam site and loss of all credit for this exercise. ECE—255, Ex 1 Sp ()9 page 2 1. Which one of the frequency spectrums shown below describes the response of the following amplifier R2 Vin Gain b‘ Gain (1) , W (2) WWWM f f Gain Gain (3) (4) f > f Gain (5) (6) None of these ECE—255, Ex 1 Sp 09 page 3 2. Figure below shows a cross section of n-type silicon wafer (reigion-l, ND=lO15 cm'3) into which we diffuse p—type dopant (region 2, NA=5xlOl6 cm'3). Then we diffuse n—type dopant (region 3,ND=1019 cm'3) into the area that we had introduced p—type dopant. What is the electron and hole concentration in region 2 Region 1, n—type uses-ashamed”, (1) nz1019,pz4.9X1016 (2) n=10‘5, p=5x1016 (3) nz2X103,pz4.9X1016 (4) n~10,pz1019 (5) nz1019,p~10 (6) None ofthese i, /6 (fig/rem 2M, ND? 50777 (1M3 f N); 5WD 9d at nmnfarwhwé ’gw’é’” Ifimrwrm Na ; Maw/VA ( ‘ ‘ W M a; w ab m we i g Hg“, W. V l , ~ - . h , e‘ S 77 77 77 77:7 b/mj figsggfi mpwéi dig}? (gifMAIW-g? t9 i?» __ M ‘4, ,, N Fl flag”: P 77v? 7 77:77 7% 7 C3 Jag»: a! 1479??“7777 My“ Amgmwf a?! (12%" i7 -' hAezflxi-Hgfi..tatlw§ £7 #77 Wig ‘2”: {V05} :- 4 ,,\ \ 72W " B ,4? ‘77 77 ‘4: Wu mafia/M m5: daft-c3"? ééélflwfififi fizAfiifXflk “ail—mg?) 26;? \ 727 W 3AM . aw, fl [K’fi/E 7’7”? My,” 76) its é” am“? i 2C? /\ €77} {agile/7f {7 @fiWfi fx‘(? 5 I) l”) r; / 57’ ECE—255, Ex 1 Sp 09 page 4 3. Figure below shows an n-type semiconductor with a doping of ND=1016 cm’3, a laser beam is pointed to the left end of the silicon at t=0 and creates excess careers at x=0 with the profile of carrier given below. What is the hole current density? Assume the hole mobility is 100 cmz/V and VT=25 mV. Laser N p(X) (cm'3) WB=l mm X (1) 4000 A/cm2 (2) 40 A/cm2 (3) 4 A/cm2 (4) 1600 A/cm2 (5) 160,000 A/crn2 (6) None of these ECE-ZSS, Ex 1 Sp 09 page 5 4. Which one of the curves shown below is the transfer characteristics (Vin-Vent) for the Clipper Circuit? “Aim-9; M am {”435} $va (1) (3) (5) (6) None of these ECE-ZSS, Ex 1 Sp 09 page 6 5. A full wave bride rectifier is shown below D1, D2, D3, and D4 have turn on voltages of’07volt If Vp=lOV, What is value of output ripple voltage at l KHz if C=l uF and R=10k§2? rm ~ . (1) 0.86V WWQ2)WQa4M3aYWW is“? 3; a A {, (3) 0.465V ,, I» W . W (4) 1v / Egg (5) 0.2V / (6) None of the above / /ssa W Ioésw l #6; 1 \l 1 \ as \sf‘ lg” @613 ECE-ZSS, Ex 1 Sp 09 page 7 6. In the Circuit shown below all three diodes are identical, and 15:10'14A, The value of I required for an output voltage of 2V is? Sta Ca mM,, 4%, dadcwgazaafir M 44;MM¥44&€ $1 a 6/“) Mi {Mae if; 1 ya a; was aataaaa Wis/W a 5A * , y {X (@465 V0 féLl‘f’ {,6 591% a; agave" . @416? 55,5 (1:32 , t , A, fag V“ "‘5 __ Q/é uaéa dam? oafié if <5 4 4 u a / , ,5 D‘ L/ i fl 1 £3 ([5? I“? T M )9 09-1? {awfif‘fi 4*? x if (1)1mA ;: 44:? f (6: 4W1] (2) 6nA g: a. . (3) For all values of l the output will be 2.1V {/7 2:: W (4) 2mA A , (5) 3f8mA a 8 . as ,_ ECE—ZSS, Ex 1 Sp ()9 page 8 7. For the circuit shown below, if a sinusoidal wave is applied to the input, which one of the curves is the output voltage? (Assume Von=0.7V) 5V Vin I lF—N F—{>{T———<V ) Out 10k Vp=l 0V t :- :— VOllt VOUt 5.7V (1) (2) t ’ -5.7V Vout VOUl 5V (3) 0.7V (4) t t V1 alt-‘63 can wig? 3% m will WW Lima 3% V V gas Fills; ”w Cg) 4.3V , (6) None of these ECE-ZSS, Ex 1 Sp 09 page 9 8. For the circuit shown below what is the value of IE? Assume VZ:6V RZ=O, 15:10'16A, BF=50 (1) z 1.8mA (2) % 3.2mA (3) N 0.15mA filellmA (5) m 2mA (6) None of the above 1: +15V w» w ECE-ZSS, Ex I Sp 09 page 10 9. Assuming the Circuit below is driven into saturation by an input voltage of VB=8V, the value of B]: is? Assume VCE(Sat)=O.2V Maj/M56» :53 at 1?C in get I M l C T a 1 Em?“ it 2’20 IQ +8 V 7, 0- 03 2/ M43 TC : (Ow 02»- (05/"5MM57 I 4;:M b/ U Mrwrffifixm (1)z100 ,} t (2) z41 . if 450‘ M 0W”) ggw ,2. 4M (5) m2 (6) None of the above [37 5? “£3” f 14.6)! is 1:: 7 4e ECE—ZSS, Ex 1 Sp 09 page ll 10. For the circuit below one measures a value of VE=2V, the value of B]: is ?? Cagwpie jg: g, 4“ I543 +101? 4qu 23W «5% l; (1) z 22 (2) ~50 W (3) z 2 «f; :1 (4) z 33 (5) m 100 (6) bleaeofflteaéove C , ...
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