Truth Tables, Characteristic Equations and Excitation Tables of Different Flipflops

Flipflops to be considered are:

  1. SR Flipflop
  2. JK Flipflop
  3. D Flipflop
  4. T Flipflop

SR Flipflop

Truth Table


S R Q(t+1)
0 0 Q(t)
0 1 0
1 0 1
1 1 Invalid inputs

Characteristic Equation

Q(t+1) = R'(t)Q(t) + S(t) ; S(t)R(t) = 0

Excitation Table

Q(t) Q(t+1) S R
0 0 0 x
0 1 1 0
1 0 0 1
1 1 x 0

JK Flipflop

Truth Table

J K Q(t+1)
0 0 Q(t)
0 1 0
1 0 1
1 1 Q'(t)

Characteristic Equation

Q(t+1) = K'(t)Q(t) + J(t)Q'(t)

Excitation Table

Q(t) Q(t+1) J K
0 0 0 x
0 1 1 x
1 0 x 1
1 1 x 0

D Flipflop

Truth Table

D Q(t+1)
0 0
1 1

Characteristic Equation

Q(t+1) = D(t)

Excitation Table

Q(t) Q(t+1) D
0 0 0
0 1 1
1 0 0
1 1 1

T Flipflop

Truth Table

T Q(t+1)
0 Q(t)
1 Q'(t)

Characteristic Equation

Q(t+1) = T'(t)Q(t) + T(t)Q'(t) = T(t) ⊕ Q(t)

Excitation Table

Q(t) Q(t+1) T
0 0 0
0 1 1
1 0 1
1 1 0

 

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