CBSE Class 12 · 1995 · SemiconductorsVery Short Answer

Find the truth table of the gate shown in the figure.

Answer: The combination gives $Y = A + A \cdot B = A$ ; truth table $00 \to 0, 10 \to 1, 01 \to 0, 11 \to 1$ .

Solution

The output of the network is

Y = A + A \cdot B

.
Taking

A

common,

Y = A (1 + B)

.
Since

1 + B = 1

in Boolean algebra,

Y = A

.
The truth table therefore simply reproduces the input

A

A = 0, B = 0 \Rightarrow Y = 0

;

A = 1, B = 0 \Rightarrow Y = 1

;

A = 0, B = 1 \Rightarrow Y = 0

;

A = 1, B = 1 \Rightarrow Y = 1

Y = A

CBSE Class 12 Board · 1995 · Subjective