NOTGatter

NOTGatter, commonly called a NOT gate or inverter, is a basic digital logic device that outputs the inverse of its single input. When the input is at a high logic level, the output is low, and when the input is low, the output is high. This simple function makes the NOT gate a fundamental building block in digital circuits.

In schematic notation, the NOT gate is often depicted as a triangle with a small circle at the output, or as a simple block with one input and one output. The standard truth table is straightforward: input 0 (false) produces output 1 (true), and input 1 (true) produces output 0 (false). In practice, logic levels are defined by the technology: for example, TTL and CMOS families use predefined voltage thresholds to represent logic 0 and 1.

The NOT gate is typically implemented using a single transistor switch in analogue form, or as a pair of transistors in CMOS technology to achieve rail-to-rail output. Key characteristics include propagation delay, which is the time the gate takes to switch after an input change, and drive strength, which affects how many downstream inputs can be driven. In CMOS, the inverter is highly power-efficient when switching and consumes negligible static power in steady states.

Applications include signal negation, level restoration, and serving as a building block for more complex gates and circuits, such as NANDs, NORs, and inverters used within flip-flops and memory cells. The NOT gate is universally supported in standard logic libraries and remains a fundamental element of digital design.