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
ABCG1N1G2F

For the logic circuit shown, how many of the 8 combinations of the inputs A, B and C give the output F = 1? Find N.

A, B, C → F
N =
2.Easy
A = 0B = 1C = 1N1G1G2F

The inputs of the logic circuit are A = 0, B = 1 and C = 1. Exactly one of its gates has the output 0. Click that gate.

A = 0B = 1C = 1
  1. 1N1
  2. 2G1
  3. 3G2
3.Medium
ABC00011110010001130204150716

Use the Karnaugh map to find the minimal sum-of-products (SOP) form of F(A, B, C) = Σm(3, 5, 6). How many product terms N does it have?

F(A, B, C) = Σm(3, 5, 6)
N =
4.Medium
MUX0I0​0I1​CI2​0I3​ABS1​S0​F

A 4-to-1 multiplexer has its select inputs S₁ = A and S₀ = B, and its data inputs tied to I₀ = 0, I₁ = 0, I₂ = C, I₃ = 0. For how many of the 8 combinations of A, B and C is the output F = 1? Find N.

I₀ = 0I₁ = 0I₂ = CI₃ = 0
N =
5.Hard
ABCD000111100001111000010312X4051716012X13015X141809011110

Find the minimal SOP form of F(A, B, C, D) = Σm(2, 6, 7, 8, 10) + d(4, 13, 14), where d marks the don't-care conditions. How many product terms N does it have?

F(A, B, C, D) = Σm(2, 6, 7, 8, 10) + d(4, 13, 14)
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 9 clock edges.

Q₃Q₂Q₁Q₀ = 11009
Q =

Answer key

  1. 1. N = 3
  2. 2. N1
  3. 3. N = 3
  4. 4. N = 1
  5. 5. N = 3
  6. 6. Q = 6

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