Reference: http://www.electrical4u.com/universal-gate-nand-nor-gate-as-universal-gate/

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UNIVERSAL GATE: NOR

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We have discussed about NOR Gate on the previous article. Now coming to the topic of this article we are going to discuss about the Universal Gate. On the previous article, I discussed that NOR Gate is considered as UNIVERSAL GATE. Now NOR has the particular property that can create any logical Boolean expression if designed in a proper way. Now we will look at the operation of NOR gate as a universal gate.

As a review, this is the NOR Gate and its Truth table:

TRUTH TABLE:

 A B Y

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0 0 1
0 1 0
1 0 0
1 1 0   





 I will now show you how to make a NOT Gate out of a NOR Gate:

 

TRUTH TABLE 

A Y

0 1

1 0

AND Gate derived from a NOR Gate:

 

 

TRUTH TABLE:

A B Y 

0 0 0

0 1 0

1 0 0

1 1 1  

Lastly, an OR Gate derived from a NOR Gate :

TRUTH TABLE:

A B Y 

0 0 0

0 1 1

1 0 1

1 1 1  

That's it! You have now created a AND, NOT, and OR Gate out of a NOR Gate. Feel free to add questions on the comment section below.

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THE  NOR  GATE

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   The Logic NOR Gate or Inclusive-NOR gate is a combination of the digital logic OR gate with that of an inverter or NOT gate connected together in series. The NOR (Not – OR) gate has an output that is normally at logic level “1” and only goes “LOW” to logic level “0” when ANY of its inputs are at logic level “1”. The Logic NOR Gate is the reverse or “Complementary” form of the OR gate.

Electronics symbol for NOR Gate

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Truth Table

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2-input NOR Gate

Symbol	Truth Table
2-input NOR Gate	B	A	Q
	0	0	1
	0	1	0
	1	0	0
	1	1	0
Boolean Expression Q = A+B	Read as A OR B gives NOT Q

 

 

3-input NOR Gate

Symbol	Truth Table
3-input NOR Gate	C	B	A	Q
	0	0	0	1
	0	0	1	0
	0	1	0	0
	0	1	1	0
	1	0	0	0
	1	0	1	0
	1	1	0	0
	1	1	1	0
Boolean Expression Q = A+B+C	Read as A OR B OR C gives NOT Q

THE 7402 IC

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          7402 IC is a device containing four independent gates each of which performs the logic NOR function. 

                           1. Output of the first NOR Gate

                           2. First input of the first NOR Gate

                           3. Second input of the first NOR Gate

                           4. Output of the second NOR Gate

                           5. First input of the second NOR Gate

                           6. Second input of the second NOR Gate
                           7. Ground/ Negative supply

                           8. First input of the third NOR Gate

                           9. Second input of the third NOR Gate 
                           10. Output of the third NOR Gate

                           11. First input of the fourth NOR Gate

                           12. Second input of the fourth NOR Gate
                           13. Output of the fourth NOR Gate

                           14.  VCC/Positive Supply 

DID YOU KNOW THAT WE CAN USE NOR GATE AS A UNIVERSAL LOGIC CIRCUIT? A NOR GATE CAN MAKE A NOT, OR, AND GATE AND ETC. FIND OUT HERE.