Recitation section number (or day/time):___________________________

PHYS345 Second Midterm Exam November 24, 1998

This is a closed book exam. One 3"x5" note card is permitted; this card should be turned in with your exam papers.

Programmable calculators and graphing calculators may be used during this exam.

Since this exam booklet may be separated for grading; it is important to:

Show ALL work on problem sheet and only on that sheet.

Please read questions carefully.

Credit may be lost inadvertently if solutions are not neat and orderly.

Be careful with units, signs, and significant figures.

1. (20 points)

Justify your answers in all cases!

  1. What is the amplitude of the pulse observed at the other end of the cable if it has been terminated with a 75 ohm resistor?     6.0 V

  2. Use Karnaugh mapping to find a suitable combination of two-input gates for this truth table.     A.B' + C.A'

  3. Suggest a single three-input gate that can replace this mess.     3-input AND

2.   (20 points)

What should R be for the lamp to flash every 1.5 sec?     11 megaohm

3.   (20 points)

What is the voltage of the signal at the oscilloscope?     4.55 V

What is the ratio of the signal voltage to the noise voltage at the oscilloscope in dB?     13.2dB

What is the new signal-to-noise ratio?     23.8dB

4.   (20 points)

Show the type of gate and the connections to the flip-flops needed:     D1 = Q'1 . Q'2

5.   (20 points)

2-bit state diagram

Last updated November 24, 1998.
Copyright George Watson, Univ. of Delaware, 1998.