Inverter (logic gate)

In digital logic, an inverter or NOT gate is a logic gate which implements logical negation. The truth table is shown on the right.

Electronic implementation

NMOS inverter

NMOS inverter

PMOS inverter

PMOS inverter

Static CMOS inverter

Static CMOS inverter

NPN transistor–transistor logic inverter

NPN transistor–transistor logic inverter

Depletion-load NMOS logic NAND

Depletion-load NMOS logic NAND

Saturated-load NMOS inverter

Saturated-load NMOS inverter

NPN resistor–transistor logic inverter

NPN resistor–transistor logic inverter

An inverter circuit outputs a voltage representing the opposite logic-level to its input. Its main function is to invert the input signal applied. If the applied input is low then the output becomes high and vice versa. Inverters can be constructed using a single NMOS transistor or a single PMOS transistor coupled with a resistor. Since this 'resistive-drain' approach uses only a single type of transistor, it can be fabricated at low cost. However, because current flows through the resistor in one of the two states, the resistive-drain configuration is disadvantaged for power consumption and processing speed. Alternatively, inverters can be constructed using two complementary transistors in a CMOS configuration. This configuration greatly reduces power consumption since one of the transistors is always off in both logic states. Processing speed can also be improved due to the relatively low resistance compared to the NMOS-only or PMOS-only type devices. Inverters can also be constructed with bipolar junction transistors (BJT) in either a resistor–transistor logic (RTL) or a transistor–transistor logic (TTL) configuration.

Gate

A gate or gateway is a point of entry to a space enclosed by walls, or a moderately sized opening in some sort of fence. Gates may prevent or control the entry or exit of individuals, or they may be merely decorative. Other terms for gate include yett and port. The word derives from the old Norse "gata", meaning road or path, and originally referred to the gap in the wall or fence, rather than the barrier which closed it. The moving part or parts of a gateway may be called "doors", but used for the whole point of entry door usually refers to the entry to a building, or an internal opening between different rooms.

A gate may have a latch to keep it from swinging and a lock for security. Larger gates can be used for a whole building, such as a castle or fortified town, or the actual doors that block entry through the gatehouse. Today, many gate doors are opened by an automated gate operator.

Types

Types of gates include:

List of scandals with "-gate" suffix

This is a list of scandals or controversies whose names in scholarly sources include a "-gate" suffix, by analogy with the Watergate scandal. This list also includes controversies that are widely referred to with a "-gate" suffix, but may be referred to by another more common name in scholarly sources (such as New Orleans Saints bounty scandal).

Etymology, usage, and history of -gate

The suffix -gate derives from the Watergate scandal of the United States in the early 1970s, which resulted in the resignation of U.S. President Richard Nixon. The scandal was named after the Watergate complex in Washington, D.C.; the complex itself was named after the "Water Gate" area where symphony orchestra concerts were staged on the Potomac River between 1935 and 1965.

The suffix is used to embellish a noun or name to suggest the existence of a far-reaching scandal, particularly in politics and government. As a CBC News column noted in 2001, the term may "suggest unethical behaviour and a cover-up". The same usage has spread into languages other than English; examples of -gate being used to refer to local political scandals have been reported from Argentina, Germany, Korea, Hungary, Greece and the former Yugoslavia.

Gate (disambiguation)

A gate is an opening in a wall or fence fitted with a moveable barrier allowing it to be closed.

Gate or GATE may also refer to:

Engineering

Electronics

Hydraulics

Other

Media and entertainment

Logic

Logic (from the Ancient Greek: λογική, logike) is the branch of philosophy concerned with the use and study of valid reasoning. The study of logic also features prominently in mathematics and computer science.

Logic was studied in several ancient civilizations, including Greece, India, and China. In the West, logic was established as a formal discipline by Aristotle, who gave it a fundamental place in philosophy. The study of logic was part of the classical trivium, which also included grammar and rhetoric. Logic was further extended by Al-Farabi who categorized it into two separate groups (idea and proof). Later, Avicenna revived the study of logic and developed relationship between temporalis and the implication. In the East, logic was developed by Hindus, Buddhists and Jains.

Logic is often divided into three parts: inductive reasoning, abductive reasoning, and deductive reasoning.

The study of logic

The concept of logical form is central to logic. The validity of an argument is determined by its logical form, not by its content. Traditional Aristotelian syllogistic logic and modern symbolic logic are examples of formal logic.

Logic (disambiguation)

Logic may refer to:

Logic may also refer to:

Entertainment

Science and technology

Boolean-valued function

A boolean-valued function (sometimes called a predicate or a proposition) is a function of the type f : X → B, where X is an arbitrary set and where B is a boolean domain, i.e. a generic two-element set, (for example B = {0, 1}), whose elements are interpreted as logical values, for example, 0 = false and 1 = true.

In the formal sciences, mathematics, mathematical logic, statistics, and their applied disciplines, a boolean-valued function may also be referred to as a characteristic function, indicator function, predicate, or proposition. In all of these uses it is understood that the various terms refer to a mathematical object and not the corresponding semiotic sign or syntactic expression.

In formal semantic theories of truth, a truth predicate is a predicate on the sentences of a formal language, interpreted for logic, that formalizes the intuitive concept that is normally expressed by saying that a sentence is true. A truth predicate may have additional domains beyond the formal language domain, if that is what is required to determine a final truth value.