In the name of God
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Hi , as far as we know , this is SR latch figure.

I am wondering how this circuit will work ?

We have not the value of Q to NOR it by S .
We have not the value of !Q to NOR it by R .

How people have drawn a truth table for it ???

Please Help me to understand..

Thanks in advance
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Get the data sheet from the link - http://www.datasheetcatalog.com/datasheets_pdf/C/D/4/0/CD4044.shtml

R-S latch states are true when one input is high and the other is low.

 

Well, if we don't know the past, you simply could start with high state in input R and low in S.
Then you get Q=0 and /Q =1
http://www.play-hookey.com/digital/rs_nor_latch.html

 

Sorry . I have not understand

I will assume that we don't know the value of Q.

 

I will assume that we don't know the value of Q.

But if you put H state to the input R, then you will have L state in Q becaues it's NOR gate.
So know you now the value of Q.

 

But
According to the first Nor gate ,it needs !Q also to NOR it with R signal.
Where is The !Q value ?
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Thanks in advance

 

But
According to the first Nor gate ,it needs !Q also to NOR it with R signal.
Where is The !Q value ?
-------------

Thanks in advance

You do not need to know !Q if you put H to R terminal.

NOR truth table

A B Q
0 0 1
0 1 0
1 0 0
1 1 0

If one or both input is HIGH (1), a LOW output (0) results

 

Thanks Jony :

Solved ....
Really Thanks .

I have got confused.

Thanks in advance.