Best Tutorial on Conversion of Flip- Flip.

In this tutorial, we are going to learn about conversion of Flip- Flip.

In this tutorial we are going to learn about below topics:

  1.  Characteristic table of desired flip-flop.
  2. Fill the excitation values inputs of given flip-flop for each combination of present state and next state.

Tables of all flip flops are given here

Present State Next State SR flip-flop inputs D flip-flop input JK flip-flop inputs T flip-flop input
Qtt Qt+1t+1 S R D J K T
0 0 0 x 0 0 x 0
0 1 1 0 1 1 x 1
1 0 0 1 0 x 1 1
1 1 x 0 1 x 0 0
  • Simplified expressions for each excitation input. If needed, use K-maps for simplifying.
  • Draw the circuit diagram of desired flip-flop according to the simplified expressions.

Conversion of some flip flops

  1. SR flip-flop to D flip-flop conversion: given flip-flop is SR flip-flop and the desired flip-flop is D flip-flop. Characteristic table is given below.
D flip-flop input Present State Next State
D Qtt Qt+1t+1
0 0 0
0 1 0
1 0 1
1 1 1

SR flip-flop has two inputs S & R. So, excitation values of SR flip-flop for each combination of present state and next state values. Characteristic table of D flip-flop along with the excitation inputs of SR flip-flop.

D flip-flop input Present State Next State SR flip-flop inputs
D Qtt Qt+1t+1 S R
0 0 0 0 x
0 1 0 0 1
1 0 1 1 0
1 1 1 x 0

Boolean functions for each input as below.

S=m2+d3S=m2+d3

R=m1+d0R=m1+d0

 K-Maps for S & R are shown below.

Conversion of Flip-Flop
Circuit Diagram of D Flip-Flop

Circuit diagram of D- flip flop

  • D flip-flop to T flip-flop conversion

Characteristic table of T flip-flop.

T flip-flop input Present State Next State
T Qtt Qt+1t+1
0 0 0
0 1 1
1 0 1
1 1 0

D flip-flop has single input D. So, excitation values of D flip-flop for each combination of present state and next state values. Characteristic table of T flip-flop along with the excitation input of D flip-flop.

T flip-flop input Present State Next State D flip-flop input
T Qtt Qt+1t+1 D
0 0 0 0
0 1 1 1
1 0 1 1
1 1 0 0

Boolean function of D as below.

D=T⊕Q(t)D=T⊕Q(t

Circuit Diagram of T Flip-Flop

Circuit diagram of T flip-flop

  • JK flip-flop to T flip-flop conversion

Characteristic table of T flip-flop.

T flip-flop input Present State Next State
T Qtt Qt+1t+1
0 0 0
0 1 1
1 0 1
1 1 0

JK flip-flop has two inputs J & K. So excitation values of JK flip-flop for each combination of present state and next state values. Characteristic table of T flip-flop along with the excitation inputs of JK flipflop.

T flip-flop input Present State Next State JK flip-flop inputs
T Qtt Qt+1t+1 J K
0 0 0 0 x
0 1 1 x 0
1 0 1 1 x
1 1 0 x 1

Boolean functions for each input as below.

J=m2+d1+d3J=m2+d1+d3

K=m3+d0+d2K=m3+d0+d2

K-Maps for J & K are shown below:-

K Map for J and K

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