top of page
Writer's picturePoornima Mani

NOR Gate as a Universal Gate

Updated: 5 days ago


NOR Gate as Universal Gate

You might have already seen the basic #logicgates before arriving at this article. #NOR gate has a special property amongst the gates. It allows users to design any logical Boolean expression using NOR gates alone if composed properly. This property is practiced to #NAND gates also.


A NOR is nothing but a gate that gives an inverted output of the OR gate. Let us take a short peek at the gate and its #truthtable.


Nor Gate

Input A Input B Output Q


  0 0 1

0 1 0

1 0 0

1 1 0


So how does this implementation actually work? Dive in right away.





NOT using NOR gate


This can be made by simply joining the two inputs of the NOR gate. Because a NOR gate is similar to an OR gate that leads to NOT gate, this immediately removes the "OR" part of the NOR gate, removing it from consideration and keeping just the NOT part.


NOT Gate




The desired output of the NOT gate is Q = NOT( A ).


Not Gate






The implementation of the NOT gate using the NOR gate is A NOR A.


OR gate using NOR gate


The NOR gate is the inverted #circuit of an OR gate. So if we invert the NOR gate again, there it is, back to the OR gate. Check out the implementation for more clarity.


OR Gate




The expected output of the OR gate is Q = A OR B.




OR Gate




The implementation of the OR gate using NOR gates is { A NOR B } NOR { A NOR B }.



AND gate using NOR gate





The output of the AND gate is TRUE only if both the inputs are TRUE. So, AND is implemented by inverting the inputs of the NOR gate.


AND Gate






The desired output of the AND gate is Q = A AND B.


And Gate








The actual implementation of AND gates using NOR gates is { A NOR A } NOR { B NOR B }.


NAND gate using NOR gate


We already saw how to implement AND using NOR gates. NAND is the inversion of AND gate and can be implemented by adding another NOR gate to reverse the output. Sounds pretty easy right?


NAND Gate





The desired implementation of the NAND gate is Q = A NAND B.


NAND Gate







The actual implementation of the NAND gate using NOR gates is [ ( A NOR A ) NOR ( B NOR B ) ] NOR [ ( A NOR A ) NOR ( B NOR B ) ].



XNOR using NOR gates


#XNOR gate can be implemented using NOR gates in two ways; one using 4 gates and other using 5 gates.


XNOR Gate







The desired implementation of the XNOR gate Q = A XNOR B.

First, let us take a look at the implementation that is most commonly used.


XNOR Gate






Here the output will be: -

{ B NOR ( A NOR B ) } NOR { A NOR ( A NOR B ) } .


There is also a conjunctive normal form that is often used. This is derived from DeMorgan's law and requires 5 nor gates for the implementation.


NOR Gate







Here the output will be: -

{ A NOR ( B NOR B ) } NOR{ B NOR ( A NOR A ) }.





XOR using NOR gates



XOR gate gives a TRUE output when an odd number of inputs are TRUE. This circuit can also be in two ways.


Xor Gate







The desired output of the XOR gate is Q = A XOR B.


The first implementation of XOR requires the use of 5 NOR gates.


XOR Gate







The output of the implementation is as: -

{ ( A NOR A ) NOR ( B NOR B ) } NOR ( A NOR B )


There is also a version of XOR using NOR gates that is often used as it has a cleaner circuit.

It is done by adding an inverter to an XNOR implementation using 4 gates.


XNOR Gate





{ A NOR ( A NOR B ) ] NOR



[ B NOR ( A NOR B ) ] } NOR

{ [ A NOR ( A NOR B ) ]

NOR [ B NOR ( A NOR B ) }


Hence we understand that any boolean circuit can be implemented using NOR gates alone. Try doing some of the #booleanexpressions by yourself using these implementations.

DRAFTJS_BLOCK_KEY:27f38You might have already seen the basic



 

See Also



Order Electronics Projects


Want us to guide you through your project or make the project for you? Click on the button below or reach out to us via Call/WhatsApp at (+91) - 7600948607


You can -


  • Order Basic Electronics Projects

  • Order Embedded Systems Projects

  • Order IoT Projects

  • Order FPGA Projects

  • Order VLSI Projects

  • Order Image Processing Projects

  • Order Matlab Projects

  • Order TinkerCAD Projects

  • Order Proteus Projects


Click on the button below to fill out the project inquiry form -





Create Various Projects


Check out our Free Arduino Projects Playlist - Arduino Projects 

Check out our Free Raspberry Pi Projects Playlist - Raspberry Pi Projects 

Check out our Free TinkerCAD Projects Playlist - TinkerCAD Projects 

Check out our Free IoT Projects Playlist - IoT Projects 

Check out our Free Home Automation Projects Playlist - Home Automation Projects 

Check out our Free NodeMCu Projects Playlist - NodeMCu Projects 


Follow us -


Please do follow us i.e. #learnelectronicsindia to get daily updates about new blogs, videos, courses, products, offers, competitions, quizzes, and Internship Opportunities.






3,048 views2 comments

Related Posts

See All

2件のコメント


Anushka Gupta
Anushka Gupta
2023年7月31日

Thanks to Learn Electronics India's exceptional blog, I'm inspired to experiment and explore the power of NOR gates in my electronics projects. The real-world examples and practical tips shared in the article make it an invaluable resource for anyone interested in digital electronics. I'm grateful for stumbling upon this gem.

いいね!

ashitanarvekar2002
2023年7月18日

LearnElectronics India simplifies complex concepts beautifully. Thank you!

いいね!
bottom of page