Question

Assertion : The logic gate $NOT$ can be built using diode.
Reason : The output voltage and the input voltage of the diode have 180${}^{\circ }$ phase difference.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (D)

$NOT$ gate inverts the input signal. The $NOT$ gate has only one input and one output. It combines the input $A$ with the output $Y$, from Boolean expression
$\bar{A}=Y$
We cannot realise a NOT gate by using diodes.

Instead a transistor has to be used. An electric circuit and truth table for a NOT gate using a $n-p-n$ transistor is shown