Name: NOT Gate
Uploaded: 2019-07-19
Duration: 4 min 12 s
Description: A NOT gate gives us an inverted output of what we provide as input. Here in this video, let us discuss the analogy and expression for this gate.

Question

Give the logic symbol, truth table and Boolean expression for the NOT gate. Explain, with a circuit diagram, how this gate is realised in practice.

Accepted Answer

The NOT gate is a one input and one output logic gate .It combine the input A with the output Y following

The boolean expression $Y = A$

Logic symbols of NOT gate is

Truth table of NOT gate

A $Y = \bar{A}$

$1$ $0$

$0$ $1$

Circuit Diagram of NOT gate is

NOT gate can be used as Practical use are as follows:

When the switch is open ( level = $0$ ) then the bulb is ON (level=1) and when the switch is closed ( level= $1$ ), the bulb is OFF ( level= $1)$

(b) NOT gate can be realised by making use of transistor as a switch as follows:

A simple 2-input logic NOT gate can be constructed using a Resistor-transistor switches as shown above with the input connected directly to the transistor base. The transistor must be saturated “ON” for an inverted output “OFF” at Q.

Give the logic symbol, truth table and Boolean expression for the NOT gate. Explain, with a circuit diagram, how this gate is realised in practice.

Important Questions on Logic Gates

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