Digital Electronics MCQs
Tech Books Yard have 64 Digital Electronics for Free Download
In a D latch
- A. data bit D is fed to S input and D^ to R input
- B. data bit D is fed to R input and D^ to S input
- C. data bit D is fed to both R and S inputs
- D. data bit D^ is not fed to any input
- Correct Answer: Option A
The number of bits in ASCII is
- A. 12
- B. 10
- C. 9
- D. 7
- Correct Answer: Option D
Assertion (A): The output of a NOR gate is equal to the complement of OR of input variables. Reason (R): A XOR gate is a universal gate.
- A. Both A and R are correct and R is correct explanation of A
- B. Both A and R are correct but R is not correct explanation of A
- C. A is true, R is false
- D. A is false, R is true
- Correct Answer: Option C
Assertion (A): A demultiplexer can be used as a decoder. Reason (R): A demultiplexer can be built by using AND gates only.
- A. Both A and R are correct and R is correct explanation of A
- B. Both A and R are correct but R is not correct explanation of A
- C. A is true, R is false
- D. A is false, R is true
- Correct Answer: Option C
A three state switch has three outputs. These are
- A. low, low and high
- B. low, high, high
- C. low. floating, low
- D. low, high, floating
- Correct Answer: Option D
In a BCD to 7 segment decoder the minimum and maximum number of outputs active at any time is
- A. 2 and 7
- B. 3 and 7
- C. 1 and 6
- D. 3 and 6
- Correct Answer: Option A
In a 7 segment display, LEDs b and c lit up. The decimal number displayed is
- A. 9
- B. 7
- C. 3
- D. 1
- Correct Answer: Option D
A counter type A/D converter contains a 4 bit binary ladder and a counter driven by a 2 MHz clock. Then conversion time
- A. 8 μ sec
- B. 10 μ sec
- C. 2 μ sec
- D. 5 μ sec
- Correct Answer: Option A
In register index addressing mode the effective address is given by
- A. index register value
- B. sum of the index register value and the operand
- C. operand
- D. difference of the index register value and the operand
- Correct Answer: Option B
A carry look ahead adder is frequently used for addition because
- A. it costs less
- B. it is faster
- C. it is more accurate
- D. is uses fewer gates
- Correct Answer: Option B