I have been looking at AND gates and noticed there are a couple different ways to build them. I am wonder when each of the circuits is better than the other:
or
Also with the first circuit I am a little confused about how it works. If x and y are 5v then q3 will turn off. Why is this?
Also, if X and Y are 0v what prevents the current from just flowing directly from the power source into Z making it 5v?
Best Answer
Really wide question and neither is really great.
Option A is better if you want to drive something low.. like pulling current down through an LED connected to 5v.
simulate this circuit – Schematic created using CircuitLab
Option B is better for the converse if you want to supply current to some load.
simulate this circuit