working of logic gates

Thread Starter

mindgame

Joined Apr 22, 2006
1
i want to have some clear concept about how actually logic gates for example AND gate. i know the truth tables but want to know the basic theory that how to get the truth table

in AND gate if we have both inputs 1 then how the output is one. and if one is zero how the output is zero.
kindly help me or send me any website that can answer the questions of how and why.
 

hgmjr

Joined Jan 28, 2005
9,029
Originally posted by mindgame@Apr 22 2006, 10:43 AM
i want to have some clear concept about how actually logic gates for example AND gate. i know the truth tables but want to know the basic theory that how to get the truth table

in AND gate if we have both inputs 1 then how the output is one. and if one is zero how the output is zero.
kindly help me or send me any website that can answer the questions of how and why.
[post=16413]Quoted post[/post]​
A great place to start is by reading througth the tutorials on this website. You should find them very helpful in explaining the basic concepts of "AND" gates at the link below.

AND gates and NAND gates Tutorial.

hgmjr
 

Dave

Joined Nov 17, 2003
6,960
Generally speaking logic gates are made from transistors organised to produce the necessary logic function. Further to the link provided by hgjmr, you are advised to look at the CMOS implementation for logic gates since this is the most common type in use in industry today:

http://www.allaboutcircuits.com/vol_4/chpt_3/8.html

A point to note about CMOS is that it is inverting by nature, therefore an AND gate is created by cascading a NAND gate with an INVERTER.

Dave
 

hgmjr

Joined Jan 28, 2005
9,029
Originally posted by Dave@Apr 22 2006, 12:23 PM
Generally speaking logic gates are made from transistors organised to produce the necessary logic function. Further to the link provided by hgmjr, you are advised to look at the CMOS implementation for logic gates since this is the most common type in use in industry today:

http://www.allaboutcircuits.com/vol_4/chpt_3/8.html

A point to note about CMOS is that it is inverting by nature, therefore an AND gate is created by cascading a NAND gate with an INVERTER.

Dave
[post=16419]Quoted post[/post]​
Good point, Dave.

CMOS should be included in any in-depth investigation into the topic of logic gate operation.

Thanks,
hgmjr
 

windoze killa

Joined Feb 23, 2006
605
Originally posted by mindgame@Apr 23 2006, 02:43 AM
i want to have some clear concept about how actually logic gates for example AND gate. i know the truth tables but want to know the basic theory that how to get the truth table

in AND gate if we have both inputs 1 then how the output is one. and if one is zero how the output is zero.
kindly help me or send me any website that can answer the questions of how and why.
[post=16413]Quoted post[/post]​
One way you can consider an AND gate is switches in series. You need both of them closed to provide an O/P. In the same vien OR gates would be switches in parallel. Either switch closed and you get an O/P.
 
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