STATE TABLE AND EQUATIONS FOR VARIOUS FLIP FLOPS SR FLIP FLOP D FLIP FLOP JK FLIP FLOP T FLIP FLOP

1. DIGITAL ELECCTRONICS
State Diagram
&
Characteristics Eq. of Sequential Circuit
PREET|patel (151310109032)
2nd Year B.E. Electrical
AIIE

2. CONTENTS:
• INTRODUCTION
• JK FLIP FLOP
• D FLIP FLOP
• SR FLIP FLOP
• T FLIP FLOP
• Conversion from SR FF to T FF

3. INTRODUCTION
• We use the truth table for explaining the relation between its inputs and outputs of a circuit
combinational.
• But the use of truth table is not suitable for explaining the input output relation for a sequential
circuit.
• Instead we use the STATE TABLE for the sequential circuits. The basic building block of a sequential
circuit is a flip flop. The outputs QA, QB etc. of such flip flops will be used as state inputs to a
sequential circuit. They are also called as state variable.
• In addition to this "x" represents an external input and Y represents the output of the sequential
circuit.
• Y will be dependent on the state variables and the external input x.

4. JK FLIP FLOP
Truth table

5. JK FLIP FLOP
P.S N.SI/P
S0 S1
0/0
0/1
0/X
QN J K QN
0 0 X 0
0 1 X 1
1 X 1 0
1 X 0 1
Excitation table

6. STATE EQUATION
• State equation is the combination of P.S and I/P to the flip-flop.
STATE Equation JK flip flop
Qn+1 = QnJ + QnK

7. D FLIP-FLOP
CHRACHTERISTIC TABLE
D QT QT+1
0 0 0
0 1 0
1 0 1
1 1 1
D
CLK

8. STATE EQUATION
• State equation is for D FLIP-FLOP is given by :
QT+1= DQ + DQ
QT+1 = D

9. SR FLIP-FLOP
CHRACHTERISTIC TABLE
QN S R QN
0 0 X 0
0 1 0 1
1 0 1 0
1 X 0 1

10. T-FLIP FLOP
CHRACHTERISTIC TABLE
T QT QT+1
0 0 0
1 0 1
1 1 0
0 1 1

11. CONVERSION FROM SR FF TO T FF
INPUT OUTPUTS
T P.S Qn N.S Qn+1 S R
0 0 0 0 X
1 0 1 1 0
1 1 0 0 1
0 1 1 X 0
0 X
1 0
X 0
0 1
T
Qn
T
Qn
S=TQn R=TQn

12. THANK YOU