NOT Gate Simulator
Use the free NOT Gate Simulator to test digital inversion instantly. Switch Input A between 0 and 1 and see the output change to the opposite logic state. A NOT gate converts 0 to 1 and 1 to 0, making it the basic inverter used throughout Boolean logic and digital electronics.
What Is a NOT Gate?
A NOT gate is a fundamental digital logic gate that has one input and one output. Its purpose is to invert, or reverse, the logical state of the input.
When the input is 0, the output becomes 1. When the input is 1, the output becomes 0. Because it always produces the opposite state, a NOT gate is also called an inverter.
NOT 1 = 0
NOT Gate Truth Table
Because a NOT gate has only one binary input, its truth table contains only two possible input states.
| Input A | Output Q |
|---|---|
| 0 | 1 |
| 1 | 0 |
How to Use the NOT Gate Simulator
Choose 0 for a LOW input or 1 for a HIGH input.
The simulator immediately changes the selected state to its logical opposite.
Input 0 produces output 1, while input 1 produces output 0.
The simulator also labels the result as HIGH / TRUE or LOW / FALSE.
Use the quick buttons to verify both possible NOT gate states.
NOT Gate Examples
NOT 0
If the input is LOW or binary 0, the inverter produces output 1.
NOT 1
If the input is HIGH or binary 1, the inverter produces output 0.
Why Is a NOT Gate Called an Inverter?
An inverter reverses the logical state applied to its input. The word “invert” means to change something to its opposite state.
HIGH → LOW Equivalent binary states: 0 → 1
1 → 0
This one-to-one inversion is exactly what a NOT gate performs.
NOT Gate Boolean Expression
Several notations can represent a NOT operation.
| Notation | Example |
|---|---|
| Word notation | NOT A |
| Overbar notation | A with a bar written above it |
| Prime notation | A' |
| Programming notation | Often ! or ~, depending on logical or bitwise context |
The notation varies between Boolean algebra, electronics, mathematics, and programming languages.
NOT Gate Symbol
The conventional NOT gate symbol is usually drawn as a triangle pointing toward the output with a small circle at the output terminal.
The small circle is called an inversion bubble. It indicates that the signal is logically inverted before reaching the output.
NOT Gate vs Binary NOT
NOT Gate
Operates on one individual digital logic signal and reverses that single state.
Binary NOT
Applies the same inversion rule independently across every bit in a longer binary value.
NOT Gate and One’s Complement
When the NOT operation is applied to every bit of a fixed-width binary number, the resulting pattern is its one’s complement.
A physical collection of NOT gates could conceptually invert each individual bit line in parallel.
Applying NOT Twice
Applying NOT to a value twice restores the original state.
NOT A = 0
NOT (NOT A) = 1
The same is true when the starting input is 0.
NOT Gate vs NAND Gate
A NOT gate has one input and directly reverses that input. NAND usually has two or more inputs and first performs AND before inverting the result.
NOT
Q = NOT A
NAND
Q = NOT(A AND B)
NOT Gate vs NOR Gate
A NOR gate combines OR and NOT. It first evaluates OR across its inputs and then inverts that result.
A standalone NOT gate has only one input and does not perform the OR step.
How a NOT Gate Works in Digital Electronics
Digital electronics uses voltage ranges to represent logical LOW and HIGH states. The NOT gate receives one input signal and drives its output toward the opposite logical state.
If the input is interpreted as LOW, the output is HIGH. If the input is interpreted as HIGH, the output is LOW.
Real-World NOT Logic Example
Imagine a status light that should turn on only when a particular signal is not active.
Output = Normal indicator If no fault exists: Fault = 0
NOT Fault = 1
The inverter turns the normally false fault state into a true normal-state signal.
NOT Gate in Control Logic
NOT gates are useful whenever a circuit needs the opposite form of an existing condition.
Active-low signals
Convert between active-high and active-low interpretations where appropriate.
Enable / Disable logic
Generate a complementary enable condition from an existing control signal.
Reset signals
Invert reset or control states when circuit logic requires the opposite polarity.
Boolean expressions
Create complemented variables required by larger logic equations.
Where Are NOT Gates Used?
Processors
Digital processors use inversion throughout control logic, arithmetic circuitry, and Boolean operations.
Embedded Systems
Microcontrollers and external logic often require inverted control or status signals.
Memory Circuits
Complementary signal states are common in latches, registers, and storage circuits.
Control Systems
Generate opposite conditions such as enabled versus disabled or active versus inactive.
Logic Design
Boolean functions often require complemented variables when building larger circuits.
Computer Science
NOT is fundamental to Boolean algebra, programming conditions, bitwise inversion, and digital circuit theory.
Important NOT Gate Properties
| Property | Rule |
|---|---|
| Zero inversion | NOT 0 = 1 |
| One inversion | NOT 1 = 0 |
| Double inversion | NOT(NOT A) = A |
| Complement rule | The output is always opposite to the input. |
NOT Gate and De Morgan’s Laws
NOT is central to De Morgan’s laws, which connect AND, OR, NAND, and NOR logic. Two fundamental identities are:
These identities are widely used when simplifying or transforming Boolean circuits.
Common NOT Gate Mistakes
A basic NOT gate is unary, meaning it operates on only one input signal.
Boolean NOT means logical inversion. Numeric sign and bitwise complement are separate concepts that depend on representation.
NOT directly inverts one input. NAND first performs AND across multiple inputs and then inverts the result.
Logical NOT generally reverses a Boolean condition, while bitwise NOT reverses each bit in a multi-bit value.
In circuit symbols, a small output circle indicates inversion and is an important visual clue.
Related BinaryCon Tools
NOT Gate Simulator FAQs
What is a NOT gate?
What is NOT 0?
NOT 0 = 1.
What is NOT 1?
NOT 1 = 0.
Why is a NOT gate called an inverter?
How many inputs does a NOT gate have?
How many rows are in a NOT truth table?
What is the Boolean expression for NOT?
NOT A, A', or using an overbar
above A depending on the notation system.
What does the circle on a NOT gate symbol mean?
What happens if NOT is applied twice?
NOT(NOT A) = A.
Is a NOT gate the same as binary NOT?
Is NOT the same as one’s complement?
What is the difference between NOT and NAND?
What is the difference between NOT and NOR?
Where are NOT gates used?
What are HIGH and LOW states?
What is logical NOT versus bitwise NOT?
Does this NOT Gate Simulator require registration?
Test NOT Gate Logic Instantly
Switch the input between LOW and HIGH, watch the output invert immediately, study the complete NOT truth table, and understand digital inversion in Boolean algebra, logic circuits, and binary computing.