Question

Write the truth table for the circuit. Why are NOR gates considered as universal gates.?

Answer 1

Hint: A NOT gate inverts its input, that is if 1 is the input 0 will be the output and similarly if 0 is the input 1 will be the output. A NOR gate is a combination of the OR gate and the NOT gate. It first performs the function of an OR gate and then NOT gate.

Complete step by step answer:
Truth table is,

$A$	$B$	$\overline A $	$\overline A + B$	$\overline {\overline A + B} $
0	0	1	1	0
0	1	1	1	0
1	0	0	0	1
1	1	0	1	0

The NOR and NAND gates are universal gates because their combination may be used to perform any of the fundamental functions, resulting in an inverter, OR gate, or AND gate. Non-inverting gates, on the other hand, lack this flexibility because they cannot create an inverter. The NOR and NAND gates are known as universal gates because they can be used to generate all other gates. NOR as NOT- this is achieved by connecting the inputs of two NOR gates. Because a NOR gate is equal to an OR gate leading to a NOT gate, this immediately eliminates the OR component of the NOR gate, leaving only the not part.

Note: The OR gate is just a NOR gate followed by a NOT gate. NOR as AND- an AND gate produces a 1 when both inputs are 1, but a NOR gate produces a 1 only when both inputs are 0. As a result, an AND gate is created by reversing the inputs of a NOR gate.