🔧

Logic Circuit to Boolean Expression

Aug 27, 2025

Overview

This lecture demonstrates how to derive a Boolean expression from a given logic circuit by analyzing its gates and connections.

Converting Circuit to Boolean Expression

  • Identify the output of the first AND gate as A AND B (AB).
  • The output of the OR gate is C OR D (C + D).
  • The output of the inverter (NOT gate) is the inverse of AB, which is (AB)'.
  • The final AND gate takes (AB)' and (C + D) as inputs, giving (AB)'(C + D).
  • The overall Boolean expression for the circuit output F is (AB)'(C + D).

Key Terms & Definitions

  • AND Gate (•) — outputs 1 only if both inputs are 1 (e.g., AB).
  • OR Gate (+) — outputs 1 if at least one input is 1 (e.g., C + D).
  • NOT Gate (') — inverts the input, turning 1 to 0 and 0 to 1 (e.g., (AB)').
  • Boolean Expression — mathematical expression representing a digital logic circuit.

Action Items / Next Steps

  • Practice converting given circuits into Boolean expressions.
  • Review the use of basic logic gates and their symbols.