Computer Knowledge

Digital Logic and Microprocessors

749 Questions

Digital logic and microprocessors form the core of computer science, covering logic gates, combinational and sequential circuits, and CPU architecture. These topics are crucial for computer knowledge sections in technical exams. Test your digital electronics basics here.

Logic gates and circuitsCombinational vs sequential circuitsMicroprocessor instructionsTruth tables and boolean functions

Digital Logic and Microprocessors Questions

Multiple choice

Directions: Carry Two Marks Each.

A function of Boolean variables X, Y and Z is expressed in terms of the minterms as

$F(X, Y, Z) = \sum(1, 2, 5, 6, 7)$

Which of the following products of sums given below is equal to the function F(X, Y, Z)?
  1. $(\bar{X} + \bar{Y}+ \bar{Z}).(\bar{X} + Y + Z).(X + \bar{Y}+\bar{Z})$
  2. $(X + Y + Z).(X + \bar{Y} + \bar{Z}).(\bar{X} + Y + Z)$
  3. $(\bar{X} + \bar{Y} + Z).(\bar{X} + y + \bar{Z}). (X + \bar{Y}+ Z).(X + Y + \bar{Z}).(X + Y + Z)$
  4. $( X + y + \bar{Z}) . (\bar{X} + Y + Z). (\bar{X} + Y + \bar{Z}).(\bar{X} + \bar{Y}+ \bar{Z})$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Multiple choice

Directions: Carry Two Marks Each.

A 1-to-8 demultiplexer with data input Din, address inputs S0, S1 and S2 (with S0 as the LSB) and $\overline{y}_o$ to $\overline{y}_7$ as the eight demultiplexed output, is to be designed using two 2 - to - 4 decoders (with enable input $\bar{E}$ and address input A0 and A1). As shown in the figure, Din, S0, S1 and S2 are to be connected to P, Q, R and S, but not necessarily in this order. The respective input connections to P, Q, R and S terminals should be

  1. S2, Din, S0 and S1

  2. S1, Din, S0 and S2

  3. Din, S0, S1 and S2

  4. Din, S2, S0 and S1
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Multiple choice

Which of the following performs boolean comparisons such as AND, OR, XOR and NOT in a CPU?

  1. Control Unit

  2. Arithmetic and Logic Unit

  3. Primary Memory

  4. Random Access Memory

  5. Read Only Memory
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

ALU (Arithmetic and Logic Unit) is an integrated circuit within a CPU that performs arithmetic and logic operations. Arithmetic instructions include addition, subtraction, and shifting operations, while logic instructions include Boolean comparisons, such as AND, OR, XOR, and NOT operations.

Multiple choice

In which of the following modes, the byte contains bits that specify a register pair, which in turn contains the address of the data in memory in 8085 processor?

  1. Register Indirect Branch Addressing Mode

  2. Direct Branch Addressing Mode

  3. Direct Addressing Mode

  4. Immediate Addressing Mode

  5. Register Indirect Mode
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Here, the byte contains bits which specify a register pair, which in turn contains the address of the data in memory in 8085 processor.