logic-gates
I need logic gate that behaves like this:
A=1, B=1, Y=1
A=0, B=0, Y=1
A=0, B=1, Y=1
A=1, B=0, Y=0
The tricky part is (A=1, B=0, Y=0) while (A=0, B=1, Y=1), AFAIK no logic gate distinquish between A or B inputs so dont think its possible with normal gate, is it possible at all?
It sounds like you want something more along the lines of a monostable multivibrator. For example, the 74HC123. This device produces a pulse of a set length when it receives an input.
The internal schematic for 1/2 the device (it's a dual) is shown here:
You can see that there are internal feedback paths (the cross-coupled NAND gates) that allow it to retain states while the external RC circuit operates.
You can treat this as a black box with this behavior:
It's definitely a 3-input NOR gate.
P V T A
0 0 0 1
1 X X 0
X 1 X 0
X X 1 0
Best Answer
I believe this is the simplest way to achieve what you are looking for:
simulate this circuit – Schematic created using CircuitLab
Edit: As KingDuken points out in the comments, this is known as an imply gate.