logic gates

jose7771 · Mar 11, 2006

hi 2 all,

i am familar with most of the digital gates, but i have seen

a type of logic which goes in this way

say A is the input and it inverted and given to a AND GATE, which
doesnt have any other input apart for A (INVERSE)

wats the meaning of this gate

regards

jose john

keithkyll · Mar 11, 2006

I am having trouble understanding your question.
Do you have an AND gate with inverting inputs?
Is the input connected to both A and B inputs?
If true, then the designer needed an Inverter. He had an extra unused AND gate. He used this gate as an inverter so he wouldn't need to add another IC.

Do you have the part number of the IC?

snimra · Mar 11, 2006

This shortcut might help. http://www.play-hookey.com/digital/derived_gates.html
All the basic gates, derived gates, flip flop, counters, etc are inside.

jvdcande · Mar 11, 2006

A and not A is a very common way to provide a fixed '0' signal. The opposite, A or not A, is commonly used to provide a fixed '1' signal.

Kind regards,

Lancie1 · Mar 11, 2006

Jose,

I think it is a way to show an Inverter (Not) gate. Inverters can be physicaly made by taking the same physical chip transisters that are used to make NAND gates (as can AND and OR gates). So,



         _ 

__A___ _| \ NOT A

      | |  )O-------

      |_|  )

        |_/

is another way to show an inverter.

jstolaruk · Mar 11, 2006

Its a inverter (NOT Gate) with a driver to increase the fanout.

Contr_Conn · Mar 11, 2006

After reading the question 4 times I think I understand it:

AND gate: one input A, second (NOT A)

B=A AND (not A)

B always false.

This is a common way to make a logical signal that is always FALSE.

logic gates

jose7771

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keithkyll

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snimra

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Lancie1

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jstolaruk

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Contr_Conn

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