Electronics and Communication Engineering - Digital Electronics

41. 

The total number of input words for 4 input OR gate is

A. 20
B. 16
C. 12
D. 8

Answer: Option B

Explanation:

24 = 16.


42. 

In digital circuits Schottky transistors are preferred over normal transistors because of their

A. lower propagation delay
B. lower power dissipation
C. higher propagation delay
D. higher power dissipation

Answer: Option A

Explanation:

Schottky transistors have low switching time and hence low propagation delay.


43. 

A flip flop is a

A. combinational circuit
B. memory element
C. arithmetic element
D. memory or arithmetic element

Answer: Option B

Explanation:

It is a memory element used in digital circuits.


44. 

A 4 bit parallel type A/D converter uses a 6 volt reference. How many comparators are required and what is the resolution in volts?

A. 0.375 V
B. 15 V
C. 4.5 V
D. 10 V

Answer: Option A

Explanation:

No. of comparators = 2n - 1 = 24 - 1 = 15

.


45. 

Quantization error occurs in

A. D/A converter
B. A/D converter
C. both D/A and A/D converter
D. neither D/A nor A/D converter

Answer: Option B

Explanation:

Analog input can have any value but digital value can have only 2N discrete levels (for N bits). Hence quantization error in A/D conversion.