I am supposed to use suitable logic symbol to design a circuit.

The output is Z with 3 active low input I1*, I2* and I3*.
My design is attached.

However, my design is not a standard logic symbol.

If I change the diagram into a NOR gate, it does not reflect that the 3 inputs are active low. What should I do?

 

That is how Horowitz and Hill do it in their book.

In fact, that exact symbol is used for an active low NOR (Table8.2).

John

 

in the exam, which symbol to use?

 

Is your professor's name Horowitz? It is acceptable to large part of the profession, including reviewers of that textbook.

Whether it is acceptable to your professor can't be known, nor can we know what was told to you in class.

John

 

Having re-read your question, an active-low AND is shown as a NOR with the inputs also inverted.

Does that help? I originally thought you were asking just whether using the inverting symbol on inputs was OK.

John

 

I originally thought you were asking just whether using the inverting symbol on inputs was OK.

That is what I wanted. thanks.

 

Some rules to remember...