Hubbry Logo
search
logo
1793996

NOR logic

logo
Community Hub0 Subscribers
Write something...
Be the first to start a discussion here.
Be the first to start a discussion here.
See all
NOR logic

A NOR gate or a NOT OR gate is a logic gate which gives a positive output only when both inputs are negative.

Like NAND gates, NOR gates are so-called "universal gates" that can be combined to form any other kind of logic gate. For example, the first embedded system, the Apollo Guidance Computer, was built exclusively from NOR gates, about 5,600 in total for the later versions. Today, integrated circuits are not constructed exclusively from a single type of gate. Instead, EDA tools are used to convert the description of a logical circuit to a netlist of complex gates (standard cells) or transistors (full custom approach).

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

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

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, joining the inputs makes the output of the "OR" part of the NOR gate the same as the input, eliminating it from consideration and leaving only the NOT part.

An OR gate is made by inverting the output of a NOR gate. Note that we already know that a NOT gate is equivalent to a NOR gate with its inputs joined.

An AND gate gives a 1 output when both inputs are 1. Therefore, an AND gate is made by inverting the inputs of a NOR gate. Again, note that a NOR gate is equivalent to a NOT with its inputs joined.

A NAND gate is made by inverting the output of an AND gate. The word NAND means that it is not AND. As the name suggests, it will give 0 when both the inputs are 1.

See all
User Avatar
No comments yet.