# Computer System Architecture Laboratory BCA 2nd

#### Assignment 1: To verify the Truth Table of Basic Logic Gates

Logic Gates:

• Fundamental building blocks of digital circuits.
• Perform logical operations on one or more binary inputs (0 or 1) and produce a single binary output.
• Essential for decision-making and calculations in computers, calculators, memory devices, and other digital systems.

Basic Gates:

• AND Gate: Outputs 1 only if all inputs are 1.
• OR Gate: Outputs 1 if at least one input is 1.
• NOT Gate: Inverts the input (0 becomes 1, 1 becomes 0).

Truth Tables:

• Tabular representations of the relationship between inputs and outputs of logic gates.
• List all possible input combinations and their corresponding output values.

Truth Tables for Basic Gates:

NOT Gate:

AND Gate:

OR Gate:

#### Assignment 2: To verify the Truth Table of Combinational Logic Gates

• XOR Gate: Outputs 1 if the inputs are different.
• XNOR Gate: Outputs 1 if the inputs are the same.

XOR Gate:

XNOR Gate:

#### Assignment 3: To verify the Truth Table of Universal Logic Gates

Universal Gates:

• NAND Gate: Outputs 1 if at least one input is 0.
• NOR Gate: Outputs 1 only if all inputs are 0. (These can be combined to create any other logic gate, hence the name “universal”)

NAND Gate:

NOR Gate:

#### Assignment 4: To verify the Truth Table of Half Adder Combinational Circuit

• It’s a tiny circuit that adds two single-digit binary numbers (0 or 1).
• It has two inputs (A and B) and two outputs:
• Sum (S): The result of adding A and B, without any carry-over.
• Carry (C): A 1 if adding A and B resulted in a “carry” to the next digit, otherwise 0.

Know the Truth Table:

Verification Methods:

a. Simulation:

• Use software like Logisim, Multisim, or Tinkercad to create a virtual Half Adder circuit.
• Apply all input combinations (00, 01, 10, 11) and observe the outputs.
• Compare the simulated outputs with the expected truth table to check for accuracy.

b. Physical Circuit:

• If available, build a physical Half Adder using logic gates (e.g., XOR, AND) and ICs (integrated circuits).
• Apply input combinations using switches or probes.
• Measure the output voltages with a multimeter or logic probe.
• Verify if the outputs match the truth table.