Combinational Logic Circuits problems
- 1. The ________ statement evaluates the variable status.
Options- A. IF/THEN
- B. IF/THEN/ELSE
- C. CASE
- D. ELSIF Discuss
Correct Answer: IF/THEN
- 2. The 7447A is a BCD-to-7-segment decoder with ripple blanking input and output functions. The purpose of these lines is to ________.
Options- A. turn off the display for any nonsignificant digit
- B. turn off the display for any zero
- C. turn off the display for leading or trailing zeros
- D. test the display to assure all segments are operational Discuss
Correct Answer: turn off the display for any nonsignificant digit
- 3. The correct output for this XOR truth table is ________.
Options- A.
- B.
- C.
- D.
Discuss
Correct Answer:
- 4. A circuit that can convert one of ten numerical keys pressed on a keyboard to BCD is a ________.
Options- A. priority encoder
- B. decoder
- C. multiplexer
- D. demultiplexer Discuss
Correct Answer: priority encoder
- 5. In VHDL, data can be each of the following types except ________.
Options- A. BIT
- B. BIT_VECTOR
- C. STD_LOGIC
- D. STD_VECTOR Discuss
Correct Answer: STD_VECTOR
- 6. A 4-bit adder has the following inputs: C0 = 0, A1 = 0, A2 = 1, A3 = 0, A4 = 1, B1 = 0, B2 = 1, B3 = 1, B4 = 1. The output will be ________.
Options- A. 01100
- B. 10101
- C. 11000
- D. 00011 Discuss
Correct Answer: 11000
- 7. In an odd-parity system, the data that will produce a parity bit = 1 is ________.
Options- A. data = 1010011
- B. data = 1111000
- C. data = 1100000
- D. All of the above Discuss
Correct Answer: All of the above
- 8. Parity generators and checkers use ________ gates.
Options- A. exclusive-AND
- B. exclusive-OR/NOR
- C. exclusive-OR
- D. exclusive-NAND Discuss
Correct Answer: exclusive-OR/NOR
- 9. When an open occurs on the input of a TTL device, the output will ________.
Options- A. go LOW, because there is no current in an open circuit
- B. react as if the open input were a HIGH
- C. go HIGH, since full voltage appears across an open
- D. still be good, if only the good inputs are used Discuss
Correct Answer: react as if the open input were a HIGH
- 10. A half-adder does not have ________.
Options- A. carry in
- B. carry out
- C. two inputs
- D. all of the above Discuss
Correct Answer: carry in
More in Digital Electronics:
Programming
Copyright ©CuriousTab. All rights reserved.