W05 ex3 soln

# W05 ex3 soln - EECS 314 Winter 2005 Exam 3 Solutions The...

This preview shows pages 1–6. Sign up to view the full content.

EECS 314 // Winter 2005 // Exam 3 // Solutions Alexander Ganago Page 1 of 25 April 6 – 19, 2005 The Key A B C D E 6 2 1 3 8 7 4 10 5 9 11 13 13 17 16 12 18 20 19 15 14 See the comment along with solution of problem 13

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
EECS 314 // Winter 2005 // Exam 3 // Solutions Alexander Ganago Page 2 of 25 April 6 – 19, 2005 Section One: 2-point questions 1 This BJT circuit is used as a logic gate. If the input and output voltages in this circuit are interpreted using positive logic, then voltages + 5 V correspond to binary “1” and voltages 0 V correspond to binary “0” Assume that positive logic is used and determine the type of this logic gate: A. AND B. OR C. NAND D. NOR E. None of the above. = = = = Each BJT acts as an open circuit if the voltage applied to its base is 0 V Each BJT acts as a short circuit if the voltage applied to its base is 5 V The two BJTs are connected in series thus, in order for the current to flow from the 5 V terminal to the ground, both should act as short circuit. It means that the current flows to the ground only if both A and B are 5 V If any of A and B is 0 V then the current does not flow to the ground. If the current flows to the ground, then the output voltage is 0 V If the current does not flow to the ground, then the output voltage is 5 V In terms of positive logic, the truth table is: A B Output 0 0 1 1 0 1 0 1 1 1 1 0 This is a NAND gate. Answer: C.
EECS 314 // Winter 2005 // Exam 3 // Solutions Alexander Ganago Page 3 of 25 April 6 – 19, 2005 2 (Contributed by Philip Choi) This circuit is given the following input: Which output plot is most appropriate? A. B. CORRECT C. D. E. None of the above Answer: The circuit is an integrator, so B is the only appropriate graph.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
EECS 314 // Winter 2005 // Exam 3 // Solutions Alexander Ganago Page 4 of 25 April 6 – 19, 2005 3 (Contributed by Philip Choi) The circuit is given 5Vsin " t ( ) input. The diode has a turn-on voltage of V DO = 0.7V . The output V out has period " . For what percentage of " is V out non-zero? A. 36.5% B. 39.5% C. 42.5% D. 45.5% CORRECT E. 48.5% Answer: V out is non-zero when 5Vsin t ( ) > 0.7V . This is 2 " 2 # sin # 1 0.7 5 \$ % & ( ) \$ % & ( ) 2 " * 0.455
EECS 314 // Winter 2005 // Exam 3 // Solutions Alexander Ganago Page 5 of 25 April 6 – 19, 2005 4 Consider the Schmitt trigger circuit shown on the diagram. The Op Amp saturates at –12 V and at +12 V. The input voltage varies from -12 V to +12 at the rate of 2 V per second, as shown on the sketch below. Which of the following waveforms correctly represents the output voltage? (On each sketch, the dashed line shows the input voltage): = = = Solution From the analytic solution given in HW 09 problem 2 assignment, the output voltage initially equals +12 V and stays at +12 V until the input exceeds +10 V (at 11sec). At the moment when the input voltage equals +10 V (at 11sec), the output immediately jumps to –12 V and stays at –12 V until the input decreases below –8 V (at 22 sec). This corresponds to waveform B shown below.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern