Note: This email comes from a student who has been reading ahead in Chapter 3. His question and my response will probably make more sense after I spend some time on it in class, which I hope to do on Wednesday.

Yale Patt

       Dr. Patt:
       I just read the section on non-progammable decision elements. My
       question is regarding AND and OR gates. I've generalized in my mind
       the difference in the construction of the two gates: OR gates have 
       p transistors arranged in series and n transistors in parallel
       while AND gates have p transistors in parallel and n transistors in
       series. Is this generalization correct?
       << name withheld to protect the eager one >> 

Actually, I would rather you did not think in terms of rules like this, since any set of rules is going to be tied thoroughly to the particular device technology that you are using, in this case p and n type transistors. AND, one can construct these gates out of many different kinds of circuits. I would much prefer you asked the question: What do I have to do in constructing the circuit to get the correct input/output behavior?

Let's see if all this makes sense after class on Wednesday.

Yale Patt