Digital logic: gates, K-maps & flip-flops worksheet with answers

Free printable Digital logic: gates, K-maps & flip-flops worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy
ABCF000?001?010?011?100?101?110?111?

The function F = (A ⊕ B)·(A + C′)′ is 1 for exactly one combination of the inputs. Click that row of the truth table.

F = (A ⊕ B)·(A + C′)′
  1. 1ABC = 000
  2. 2ABC = 001
  3. 3ABC = 010
  4. 4ABC = 011
  5. 5ABC = 100
  6. 6ABC = 101
  7. 7ABC = 110
  8. 8ABC = 111
2.Easy
ABCN1: 2 nsG13 nsN2: 1 nsG26 nsG35 nsF

The propagation delay of every gate is written under it. Find the worst-case propagation delay tpd from the inputs to the output F.

N1: 2 nsN2: 1 nsG1: 3 nsG2: 6 nsG3: 5 ns
tpd = ns
3.Medium
ABC00011110010011131204050706

Use the Karnaugh map to find the minimal sum-of-products (SOP) form of F(A, B, C) = Σm(1, 2, 3). How many product terms N does it have?

F(A, B, C) = Σm(1, 2, 3)
N =
4.Medium
ABC000111100101324576

Simplify F = AB + ABC′ + AB′C′ + AC to its minimal sum-of-products form. How many literals L does the simplified expression contain?

F = AB + ABC′ + AB′C′ + AC
L =
5.Hard
ABCD000111100001111010010312X4X50706X120130150140819011110

For F(A, B, C, D) = Σm(0, 2, 9, 10) + d(4, 5, 12), where d marks the don't-care conditions, find the number N of essential prime implicants.

F(A, B, C, D) = Σm(0, 2, 9, 10) + d(4, 5, 12)
N =
6.Hard
DQ3​Q3​DQ2​Q2​DQ1​Q1​DQ0​Q0​CLKRING

A 4-bit ring counter Q₃Q₂Q₁Q₀ starts at 1100. At every clock edge the bits shift one place to the right (Q₃ → Q₂ → Q₁ → Q₀) and Q₃ receives Q₀. Give the state Q = Q₃Q₂Q₁Q₀ as a decimal number after 6 clock edges.

Q₃Q₂Q₁Q₀ = 11006
Q =

Answer key

  1. 1. ABC = 011
  2. 2. tpd = 12 ns
  3. 3. N = 2
  4. 4. L = 1
  5. 5. N = 2
  6. 6. Q = 3

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