Logic Circuits & Truth Tables

An combination of inputs into a logic circuit return a unique output or series of outputs. Both inputs and outputs are represented by 0's and 1's, which represent on and off states. We can use the truth tables for each logic gate to determine the state at each point in the circuit hence the output from the circuit. Thus is represented in the truth table below the logic circuit.

A

B

C

D=NOT B

E=A OR B

F=C OR D

G=E AND F

1

1

1

0

1

1

1

1

1

0

0

1

0

0

1

0

1

1

1

1

1

1

0

0

1

1

1

1

0

1

1

0

1

1

1

0

1

0

0

1

0

0

0

0

1

1

0

1

0

0

0

0

1

0

1

0