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
A = 1B = 1C = 0G1G2G3F

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

A = 1B = 1C = 0
  1. 1G1
  2. 2G2
  3. 3G3
2.Easy
ABCN1G1N2G2G3F

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 =
3.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 =
4.Medium
ABCD000111100001111010111302140507160121131150140809111010

Use the Karnaugh map to find the minimal product-of-sums (POS) form of F(A, B, C, D) = Σm(0, 1, 3, 4, 6, 11, 13, 15). How many sum terms (factors) N does it have?

F(A, B, C, D) = Σm(0, 1, 3, 4, 6, 11, 13, 15)
N =
5.Hard
CLKJK1234567

A positive-edge-triggered JK flip-flop starts with Q = 0 and receives the inputs shown at 7 rising clock edges. How many times N does Q change state?

Q₀ = 0JK
N =
6.Hard
ABCD0001111000011110000103X2X4051716X12X13X151141819111010

Find the minimal SOP form of F(A, B, C, D) = Σm(6, 7, 8, 9, 11, 14) + d(2, 4, 12, 13, 15), where d marks the don't-care conditions. How many literals L does it contain?

F(A, B, C, D) = Σm(6, 7, 8, 9, 11, 14) + d(2, 4, 12, 13, 15)
L =

Answer key

  1. 1. G3
  2. 2. N = 3
  3. 3. N = 4
  4. 4. N = 4
  5. 5. N = 4
  6. 6. L = 6

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