Re-designing logic gate

Thread Starter

Lewy Willy

Joined Nov 23, 2016
8
I'm having trouble minimizing the number of gates in a logic gate. Could someone give me the best method of doing this by using k-maps? thanks
 

dl324

Joined Mar 30, 2015
16,845
Welcome to AAC!

You don't give enough information for anyone to help you; with emphasis on help. We don't generally simply give answers because it deprives you of the opportunity to learn.

Is this homework?
 

WBahn

Joined Mar 31, 2012
29,978
I'm having trouble minimizing the number of gates in a logic gate. Could someone give me the best method of doing this by using k-maps? thanks
What does it mean to minimize the number of "gates" in a logic "gate"? What do you mean by a "gate"? Do you mean the same thing both places where you use the word?

Who says that you can always minimize the number of gates using a K-map?

Does a four-input NAND gate count as a single gate?

Does a four-input NAND gate count as the same number of gates as a four-input AND gate?

How many gates does a two-input XOR gate count as?
 

Thread Starter

Lewy Willy

Joined Nov 23, 2016
8
What does it mean to minimize the number of "gates" in a logic "gate"? What do you mean by a "gate"? Do you mean the same thing both places where you use the word?

Who says that you can always minimize the number of gates using a K-map?

Does a four-input NAND gate count as a single gate?

Does a four-input NAND gate count as the same number of gates as a four-input AND gate?

How many gates does a two-input XOR gate count as?
I'm required to re-implement a logic gate's functionality using the minimum number of gates possible using K-maps.
 

hp1729

Joined Nov 23, 2015
2,304
I'm required to re-implement a logic gate's functionality using the minimum number of gates possible using K-maps.
???
Number of gates = number of gates
Do you mean number of transistors in a gate? Number of gates is just a matter of drawings representing gates. Otherwise your task has been accomplished by those who went before you.
What gates would you like to simplify? Maybe that would help.
 

Thread Starter

Lewy Willy

Joined Nov 23, 2016
8
???
Number of gates = number of gates
Do you mean number of transistors in a gate? Number of gates is just a matter of drawings representing gates. Otherwise your task has been accomplished by those who went before you.
What gates would you like to simplify? Maybe that would help.
Here's a screenshot of what I'm having trouble with;
https://s13.postimg.org/5b4fj7513/Selection_095.png

I'm to remove as many gates as possible.
 

absf

Joined Dec 29, 2010
1,968
I am moving you one step closer to your target...

Can you make your logic diagram into functional formulas and fill in the values of X, Y, & Z?

Selection_095.png LOGIC 2.PNG

/C = NOT C
* = AND
+ = OR

X was already done for you.

Allen
 

WBahn

Joined Mar 31, 2012
29,978
I am moving you one step closer to your target...

X was already done for you.
In other words, you have robbed him of the opportunity that the instructor was offering to exercise and develop his skills by just doing his work for him without even attempting to guide him into seeing how to discover any part of it for himself.

I'm sure that is going to help out a lot come exam time.
 

Thread Starter

Lewy Willy

Joined Nov 23, 2016
8
I am moving you one step closer to your target...

Can you make your logic diagram into functional formulas and fill in the values of X, Y, & Z?

View attachment 115846 View attachment 115847

/C = NOT C
* = AND
+ = OR

X was already done for you.

Allen
Hi, I tried to pm you but looks like this forum doesn't have that enabled. Could you tell me how you got the values of X?

While looking for the pm button on your profile, i saw you're from malaysia. Sy sebelum tinggal disana, kini tinggal di indonesia :)
 

absf

Joined Dec 29, 2010
1,968
Hi, I tried to pm you but looks like this forum doesn't have that enabled. Could you tell me how you got the values of X?

While looking for the pm button on your profile, i saw you're from malaysia. Sy sebelum tinggal disana, kini tinggal di indonesia :)
That shouldn't be too hard.

X=(A*B)*(/B*B)

When A=0, B=0, X=(0*0)*(1*0)=0
When A=0, B=1, X= (0*1)*(0*1)=0
When A=1, B=0, X= (1*0)*(1*0)=0
When A=1, B=1, X= (1*1)*(0*1)=0

OR...... (/B*B) is always 0, so anything AND (/B*B) = 0;:D

Allen
 
Last edited:

Thread Starter

Lewy Willy

Joined Nov 23, 2016
8
I am moving you one step closer to your target...

Can you make your logic diagram into functional formulas and fill in the values of X, Y, & Z?

View attachment 115846 View attachment 115847

/C = NOT C
* = AND
+ = OR

X was already done for you.

Allen
Hi, I tried to pm you but looks like this forum doesn't have that enabled. Could you tell me how you got the values of X?

While looking for the pm button on your profile, i saw you're from malaysia. Sy sebelum tinggal disana, kini tinggal di indonesia
That shouldn't be too hard.

X=(A*B)*(/B*B)

When A=0, B=0, X=(0*0)*(1*0)=0
When A=0, B=1, X= (0*1)*(0*1)=0
When A=1, B=0, X= (1*0)*(1*0)=0
When A=1, B=1, X= (1*1)*(0*1)=0

OR (/B*B) is always 0, so anything AND (/B*B) = 0;:D

Allen
So by that logic, the first value for Y is 0?
 

absf

Joined Dec 29, 2010
1,968
Nope....

Y=(A*C) + (B + /C)

On the first line, A=0 B=0 C=0 D=0 // D is not applicable here

Y = (0*0) + (0 + 1) // C=0 so /C=1
Y = 0 + 1
=1

Allen
 

WBahn

Joined Mar 31, 2012
29,978
I meant 3. I didn't look at that properly, I blame my lack of sleep. Embarrassing :confused:
Okay, but now consider that we are talking BOOLEAN algebra, not normal arithmetic.

In Boolean algebra, + is not addition, it is merely a symbol that looks like an addition symbol, but is really the symbol for the OR operator. Similarly, * is not multiplication, but the AND operator.

So 1 + 1 + 1 + 1 = 1
 
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