Hi All,

I'm stuck on the following question, any advice would be greatly received (thank you).

So far I have . . . .

The Boolean expression for a NAND gate is Q=(AB)' which is to say the inverse of AB and so the truth table would be as per below:

(It won't let me add the table??)

From this table we can see that the gate only gives a high output if both its inputs are low.

If we look at our required output Q, we find the expression in brackets is an OR one, as we are adding together, and the whole expression is an AND, as we are multiplying.

When we apply De Morgan's Law we can make the whole thing an expression of OR statements and construct an NAND circuit around that.

As we know De Morgan's Law consists of two theorems that state, and when using a computer it is sometimes difficult to get the symbols correct therefore it is common to write:

(A+B)'= (AB)' and (AB)' = (A+B)'

Applying De Morgan's Law to (A+B)(A+C) gives us (A+B)' + (A+C)' and turns the whole thing into an OR. However if we negate only once we get the inverse of what we need and so we double negate. . . . . don't we??

I'm stuck on the following question, any advice would be greatly received (thank you).

**Starting with the following statement:****(A+B).(A+C)****Show how this can be implemented using NAND gates using De Morgans law.**So far I have . . . .

The Boolean expression for a NAND gate is Q=(AB)' which is to say the inverse of AB and so the truth table would be as per below:

(It won't let me add the table??)

From this table we can see that the gate only gives a high output if both its inputs are low.

If we look at our required output Q, we find the expression in brackets is an OR one, as we are adding together, and the whole expression is an AND, as we are multiplying.

When we apply De Morgan's Law we can make the whole thing an expression of OR statements and construct an NAND circuit around that.

As we know De Morgan's Law consists of two theorems that state, and when using a computer it is sometimes difficult to get the symbols correct therefore it is common to write:

(A+B)'= (AB)' and (AB)' = (A+B)'

Applying De Morgan's Law to (A+B)(A+C) gives us (A+B)' + (A+C)' and turns the whole thing into an OR. However if we negate only once we get the inverse of what we need and so we double negate. . . . . don't we??

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