Like NAND gate

NAND logic

NAND gates are one of the two basic logic gates from which any other logic gates can be built. Due to this property, NAND and NOR gates are sometimes called "universal gates". However, modern integrated circuits are not constructed exclusively from a single type of gate...

s, NOR gates are so-called "universal gates" that can be combined to form any other kind of logic gate

Logic gate

A logic gate is an idealized or physical device implementing a Boolean function, that is, it performs a logical operation on one or more logic inputs and produces a single logic output. Depending on the context, the term may refer to an ideal logic gate, one that has for instance zero rise time and...

. For example, the first embedded system

Embedded system

An embedded system is a computer system designed for specific control functions within a larger system. often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal...

, Apollo Guidance Computer

Apollo Guidance Computer

The Apollo Guidance Computer provided onboard computation and control for guidance, navigation, and control of the Command Module and Lunar Module spacecraft of the Apollo program...

, was built exclusively from NOR gates, about 5,600 in total for the later versions. Today, integrated circuit

Integrated circuit

An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...

s are not constructed exclusively from a single type of gate. Instead, EDA

Electronic design automation

Electronic design automation is a category of software tools for designing electronic systems such as printed circuit boards and integrated circuits...

 tools are used to convert the description of a logical circuit to a netlist

Netlist

The word netlist can be used in several different contexts, but perhaps the most popular is in the field of electronic design. In this context, a "netlist" describes the connectivity of an electronic design....

 of complex gates (standard cell

Standard cell

In semiconductor design, standard cell methodology is a method of designing application-specific integrated circuits with mostly digital-logic features. Standard cell methodology is an example of design abstraction, whereby a low-level very-large-scale integration layout is encapsulated into an...

s) or transistors (full custom

Full custom

Full-custom design is a methodology for designing integrated circuits by specifying the layout of each individual transistor and the interconnections between them...

 approach).

NOR

Nor

Nor may refer to:*In grammar, nor is a coordinating conjunction*Nór, the eponymous founder-king of Norway in Norse mythology*Nor , a character in the book in Wicked...

A NOR gate is logically an inverted OR gate. By itself has the following truth table:

EWLINE Truth Table Input A Input B Output Q 0 0 1 0 1 0 1 0 0 1 1 0

Making other gates by using NOR gates

A NOR gate is a universal gate, meaning that any other gate can be represented as a combination of NOR gates.

NOT

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.This represents perfect switching behavior, which is the defining assumption in Digital electronics. In practice, actual devices have electrical characteristics that...

This is made by joining the inputs of a NOR gate. As a NOR gate is equivalent to an OR gate leading to NOT gate, this automatically sees to the "OR" part of the NOR gate, eliminating it from consideration and leaving only the NOT part.

Desired Gate	|NOR Construction
EWLINE Truth Table Input A Output Q 0 1 1 0

OR

OR gate

The OR gate is a digital logic gate that implements logical disjunction - it behaves according to the truth table to the right. A HIGH output results if one or both the inputs to the gate are HIGH . If neither input is HIGH, a LOW output results...

The OR gate is simply a NOR gate followed by a NOT gate.

Desired Gate	|NOR Construction
EWLINE Truth Table Input A Input B Output Q 0 0 0 0 1 1 1 0 1 1 1 1

AND

AND gate

The AND gate is a basic digital logic gate that implements logical conjunction - it behaves according to the truth table to the right. A HIGH output results only if both the inputs to the AND gate are HIGH . If neither or only one input to the AND gate is HIGH, a LOW output results...

An AND gate gives a 1 output when both inputs are 1; a NOR gate gives a 1 output only when both inputs are 0. Therefore, an AND gate is made by inverting the inputs to a NOR gate.

Desired Gate	|NOR Construction
EWLINE Truth Table Input A Input B Output Q 0 0 0 0 1 0 1 0 0 1 1 1

NAND

Nand

NAND may stand for:*Nand , an Indian classical raga.*Logical NAND , a binary operation in logic.**NAND gate, an electronic gate that implements a logical NAND....

A NAND gate is made using an AND gate in series with a NOT gate:

Desired Gate	|NOR Construction
EWLINE Truth Table Input A Input B Output Q 0 0 1 0 1 1 1 0 1 1 1 0

XOR

An XOR gate is made by connecting the output of 3 NOR gates (connected as an AND gate) and the output of a NOR gate to the respective inputs of a NOR gate. This expresses the logical fomula (A AND B) NOR (A NOR B). This construction entails a propagation delay three times that of a single NOR gate.

Desired Gate	|NOR Construction
EWLINE Truth Table Input A Input B Output Q 0 0 0 0 1 1 1 0 1 1 1 0

XNOR

An XNOR gate can be constructed from four NOR gates implementing the expression "(A NOR N) NOR (B NOR N) where N = A NOR B".This construction has a propagation delay three times that of a single NOR gate, and uses more gates.

Desired Gate	|XNOR Construction
EWLINE Truth Table Input A Input B Output Q 0 0 1 0 1 0 1 0 0 1 1 1

See also

• NAND Logic
  NAND logic
  NAND gates are one of the two basic logic gates from which any other logic gates can be built. Due to this property, NAND and NOR gates are sometimes called "universal gates". However, modern integrated circuits are not constructed exclusively from a single type of gate...
  
  . Like NOR gates, NAND gates are also universal gates.