# D Flip-Flop

Discussion in 'Homework Help' started by battery, Jan 28, 2009.

1. ### battery Thread Starter New Member

Jan 28, 2009
4
0
Just wanted check if i understand correctly -

Here is the DFlip FLop

In the start all triggers have info of hex A (base 16) (meaning 1 0 1 0).
the question - 1) what info will be in these triggers after 1. , 2. , 3. , and 4. impulse.

As i understand this scheme makes a loop -
after first impulse there will be - 0 1 0 1
after second - 1 0 1 0
third - 0 1 0 1
and fourth - 1 0 1 0

Am i right? Or have i understood this completely wrong.

2. ### mik3 Senior Member

Feb 4, 2008
4,846
63
Is the input of the second flip flop connected to the Q' of the first flip flop? Or it is just a mistake and it should be connected to Q?

3. ### battery Thread Starter New Member

Jan 28, 2009
4
0
Eh, there is no mistake, for some reason i didn`t notice that.

So, it`s not as easy as i thought. So all the 0`s and 1`s are inverted when they go into the first flipflop ?

4. ### mik3 Senior Member

Feb 4, 2008
4,846
63
Yes, at each impulse Q3=Q0, Q2=Q0', Q1=Q2 and Q0=Q1.

5. ### battery Thread Starter New Member

Jan 28, 2009
4
0
i hope that this is correct now -
impulses
1) 1101
2) 0011
3) 1110
4) 0101

Feb 4, 2008
4,846
63
I find

1010
0101
1010
0101

7. ### battery Thread Starter New Member

Jan 28, 2009
4
0
Interesting, it looks like something i wrote in my first try.

So by giving the first impulse the numbers don`t switch ?

8. ### mik3 Senior Member

Feb 4, 2008
4,846
63
They change!!

9. ### Cabwood Member

Feb 8, 2009
20
0
After each pulse:
Q3 becomes whatever Q0 was before the pulse,
Q2 becomes the inverse of whatever Q3 was before the pulse,
Q1 becomes whatever Q2 was before the pulse and
Q0 becomes whatever Q1 was before the pulse.

This gives me:
at start: 1010
after pulse 1) 0001
after pulse 2) 1100
after pulse 3) 0010
after pulse 4) 0101