types of flip flops-JK,SR,D & T-truth tables

1. Contents:
• Various types of Flip-flops
 SR Flip-flop
 D Flip-flop
 JK Flip-Flop
 T Flip-flop
Kongunadu College of Engineering & Technology Flip-Flops 1

2.  In SR flip-flop the clock pulse is followed by edge
detector circuit which act as a differentiator.
2
Kongunadu College of Engineering & Technology
Flip-Flops

3. S R Qn Qn+1 State
0 0 0 0
No Change(NC)
0 0 1 1
0 1 0 0
Reset
0 1 1 0
1 0 0 1
Set
1 0 1 1
1 1 0 X
Indeterminate
1 1 1 X
Truth Table
Kongunadu College of Engineering & Technology Flip-Flops 3

4. Kongunadu College of Engineering & Technology Flip-Flops 4

5. D Qn+1
0 0
1 1
X Qn
• The basic building block of D flip-flop is a SR flip-flop.
• The D flip-flop is also known as delay flip-flop
Truth Table
Kongunadu College of Engineering & Technology Flip-Flops 5

6.  The uncertainty in the state of an SR flip-flop when S=R=1 can
be eliminated by converting it into a JK flip-flop  S=J𝑄 and
R=KQ
Kongunadu College of Engineering & Technology Flip-Flops 6

7. J K Qn Qn+1
0 0 0 0
0 0 1 1
0 1 0 0
0 1 1 0
1 0 0 1
1 0 1 1
1 1 0 X
1 1 1 X
Truth Table
Kongunadu College of Engineering & Technology Flip-Flops 7

8. Kongunadu College of Engineering & Technology Flip-Flops 8

9. Kongunadu College of Engineering & Technology Flip-Flops 9

10. Qn T Qn+1
0 0 0
0 1 1
1 0 1
1 1 0
 T flip-flop is also known as “Toggle flip-flop”.
 It is the modification of the JK flip-flop.
 It is obtained from a JK flip-flop by connecting both
inputs, J and K together.
 When T=0, J=K=0 and hence there is no change in
the output. When T=1, J=K=1 and hence output
toggles.
Kongunadu College of Engineering & Technology Flip-Flops 10

11. The structure of various types of flip-flops and their
truth tables are explained in detail.
References:
 Mandal, “Digital Electronics Principles & Application,
McGraw Hill Edu, 2013.
 William Keitz, Digital Electronics-A Practical Approach with
VHDL, Pearson, 2013.
 Thomas L.Floyd, ‘Digital Fundamentals’, 11th edition,
Pearson Education, 2015.
 Charles H.Roth, Jr, Lizy Lizy Kurian John, ‘Digital System
Design using VHDL, Cengage,2013.
 D.P.Kothari,J.S.Dhillon, ‘Digital circuits and Design’,Pearson
Education, 2016.
 A.P.Godse., Dr.D.A.Godse, ‘Digital Logic Circuits’ , Technical
Publications Third Edition 2016
 Other Web Sources
Kongunadu College of Engineering & Technology Flip-Flops 11