372
Figure PB-10
8-11. What state do the outputs of a 7442 BCD decoder go to when an
invalid BCD number (10 to 15) is input to Ag to As?
8-12. Design a circuit, based on a 74154 4-line-to-16-line decoder,
that will output a HIGH whenever the 4-bit binary input is greater than
12. (When the binary input is less than or equal to 12, it will output
a LOW)
Section 8-5
8-13. Determine the four outpot levels in Figure 8-25(a) given the following
inputs
(a) 7-7-000111111
(b)77-11101111
(c) 7--0
8-14. Determine the five output levels in Figure 8-29) given the following
inputs
(a)
11111101.27
(b) 77-00000000, 27
0
0
8-15. Sketch the waveforms (AEO,G3) given the inputs shown
in Figure PS-15(b) to the 74148 of Figure P8-15(a),
8-16. Repeat Problem 8-15 for the waveforms shown in Figure P8-16,
8-17. Two 74148s and connected in Figure P8-17 to form an active
LOW input, active-LOW output hexadecimal (16-line-1-4-line) priority
encoder. Show the logic levels on each line in Figure P8-17 for encod
ing an inpot hexadecimal C (12) to an output binary 1100 (active-LOW
00111
8-18. Repeat Problem 8-17 for encoding an input hexadecimal 6 to an
output binary six (active-LOW 1001),
CHAPTER & CODE CONVERTERS, MULTIPLEXERS, AND DEMULTIPLEXERS
