Cross-Coupled Nor Gate Cell and Cross-Coupled Nand Gate Cell

[shermaine]

Hello,

How does a cross-coupled nor gate and nand gate cell functioned?
Pls advise.
Thanks.

 

[Russlk]

They become a set-reset flip-flop. Do you have a specific question?

 

[shermaine]

How to determine when it is set, reset or remain?
Pls advise.
I dun understand how the croo-coupled works?

 

[Russlk]

First, you have to understand how the NAND gate works. When both inputs are positive (high), the output is low. When either input is low, the output is high. In the diagram below, if both A in and B in are low, both outputs will be high. That is not a useful state. If both inputs are high, then A out and B out cannot both be high and both outputs cannot be low either. So, one has to be high and the other low. You don't know which is which unless you force it by taking either A or B low, then you know which output is high. OK?

 

[shermaine]

what if Aout is Q(bar) and Aout is Q?
Does the ouput depends on the input coming from Aout also?
Pls advise.
Thanks.

 

[Russlk]

Did you mean Bout is Q? The output only depends on whether Ain or Bin is taken low. The state of the output before that is not important.

 

[erika14344]

thank you guys for the lecture!!! this is just what i need!

i registered here as a token of my appreciation coz
the forum helped alot!