# Important Questions of Logic Gates

In this post, some of the important questions of logic gates are given. It includes basic gates, two level of gates, positive logic, negative logic, logic circuit, all or nothing circuit, any or all gate, inverter gate, universal gate, meaning of AOI circuit, bubble OR gate, active low OR gate.

## Basic Gates

Which are the three basic gates?

• AND, OR and NOT

Which are the two logic levels of any gate?

Logic level : Low and High       OR    True and False    OR

One and Zero

## Positive logic and Negative Logic

What is meaning of Positive logic and Negative logic?

Positive logic

• It is a logic system in which the higher of the two voltage level represents logic 1 and lower of the two voltage level represents logic 0.

Negative logic

• It is a logic system in which the higher of the two voltage level represents logic 0 and lower of the two voltage level represents logic 1.

Explain the term : Logic circuit

Logic circuit

• The interconnection of various gates to perform various logic functions is called as logic circuit.

Which gate is known as all or nothing gate? Why?

• The AND gate is known as all or nothing gate because the output is 1 if and only if all its inputs are 1.

Which gate is known as any or all gate?

• The OR gate is known as any or all gate because the output is 1 even if one of its input is 1.

What is condition for high output of AND gate?

• All inputs must be high.

What is condition for high output of OR gate?

• Any of one input is high

Which gate is also known as inverter gate?

• NOT gate

Which gate has only one input?

• NOT gate

## Universal Gate

Which gate is known as universal gate? Why?

Universal Gate

• The NAND and NOR gates are known as universal gate because any gates as well as complex logic circuit can be realized by the NAND and NOR gates.

## AOI Circuit

What is meaning of the AOI circuit?

AOI circuit

• A logic circuit which use three gates AND, OR and INVERT is called as AOI circuit.

What is bubble OR gate?

Bubble OR gate

• The OR gate with inverter input is called as bubble OR gate.

Why the NAND gate is called as active low OR gate?

Active low OR gate

• The NAND gate is called as active low OR gate because the output is at high state even if any of its input is low.