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
ABCN1: 3 nsN2: 3 nsG15 nsG25 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: 3 nsN2: 3 nsG1: 5 nsG2: 5 nsG3: 5 ns
tpd = ns
2.Easy
A = 1B = 0C = 1N1G1G2F

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

A = 1B = 0C = 1
  1. 1N1
  2. 2G1
  3. 3G2
3.Medium
ABC00011110011001030214151716

Use the Karnaugh map to find the minimal product-of-sums (POS) form of F(A, B, C) = Σm(0, 4, 5, 6, 7). How many sum terms (factors) N does it have?

F(A, B, C) = Σm(0, 4, 5, 6, 7)
N =
4.Medium
MUXCI0​1I1​0I2​CI3​ABS1​S0​F

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

I₀ = CI₁ = 1I₂ = 0I₃ = C
N =
5.Hard
ABCD0001111000011110100103X2X4050706X120130150141809111110

For F(A, B, C, D) = Σm(0, 8, 10, 11) + d(2, 4, 12), where d marks the don't-care conditions, find the number N of essential prime implicants.

F(A, B, C, D) = Σm(0, 8, 10, 11) + d(2, 4, 12)
N =
6.Hard
ABCD0001111000011110X001X312040517061121131150140809111010

For F(A, B, C, D) = Σm(2, 7, 11, 12, 13, 15) + d(0, 3), where d marks the don't-care conditions, find the number N of essential prime implicants.

F(A, B, C, D) = Σm(2, 7, 11, 12, 13, 15) + d(0, 3)
N =

Answer key

  1. 1. tpd = 13 ns
  2. 2. G1
  3. 3. N = 2
  4. 4. N = 4
  5. 5. N = 1
  6. 6. N = 2

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