Logic Circuits

Logic-Circuits

Logic Circuits

  • Logic gate symbols
  • Logic circuits design
  • Minimization of logic circuits

Logic Gates

*LogicalGate

  • Buffer
    • It is used for delay
    • Useful for timing purpose
    • Not for the logical purpose
    • Buffer

Logic Circuit

LogicalGate01

LogicalGate02

  • Steps in Design of Logical Circuits (Without minimization)
  1. Find the inputs and outputs
    • Inputs: number of variables in the Boolean function
    • Outputs: how many functions are required
  2. Draw the truth table
    • Truth table: indicate the relationship between outputs and inputs
    • Specify what ‘0’ and ‘1’ (in input and output) in the table represent?
  3. Figure out the functions
    • Use sum of products or product of sums
  4. Design the logical circuits

Logic Circuits – Half Adder

  • Add two bits
    • 0 + 0 = 0
    • 0 + 1 = 1
    • 1 + 0 = 1
    • 1 + 1 = 0 and carry 1 to the next place
  • HalfAdder
  • S: 本位
  • C: 进位
  • HalfAdder

Logic Circuit - Full Adder

Full-Adder

Steps in Design of Logical Circuits(With Minimization)

  1. Find the inputs and outputs
    • Inputs: number of variables in the Boolean function
    • Outputs: how many functions are required
  2. Draw the truth table
    • Truth table: indicate the relationship between outputs and inputs
    • Specify what ‘0’ and ‘1’ (in input and output) in the table represent?
  3. Figure out the functions
    • Use sum of products or product of sums
  4. Minimization of the Boolean functions if possible
  5. Design the logical circuits

Karnaugh-Map

KM_1

KM_2

KM_3

KM_4

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