Computer Knowledge

Digital Logic and Microprocessors

735 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

The circuit shown below consists of JK flip-flops, each with an active low asynchronous reset ($\bar{R}_d$ input). The counter corresponding to this circuit is

  1. a modulo-5 binary up counter

  2. a modulo-6 binary down counter

  3. a modulo-5 binary down counter

  4. a modulo-6 binary up counter
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

From the figure, it can be seen that it is a basic modulo UP counter configuration because clock is negative edge triggering at modulo-5.

Multiple choice

A universal logic gate can implement any Boolean function by connecting sufficient number of them appropriately. The three are as follows:

Which of the following statements is TRUE?

  1. Gate 1 is a universal gate.

  2. Gate 2 is a universal gate.

  3. Gate 3 is a universal gate.

  4. None of the gates shown is a universal gate.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In general, the only universal gates are NAND and NOR gates, but none of the given gates is NAND or NOR gate. However, we must observe gate 3. All the Boolean functions can be implemented by using this gate. Hence, it is a universal gate.

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.