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
ABCG1G2G3F

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
ABC0001111001

Click the cell of the 3-variable Karnaugh map that belongs to minterm m1 (variables A, B, C with A the most significant bit).

m1
  1. 1A = 0, BC = 00
  2. 2A = 0, BC = 01
  3. 3A = 0, BC = 11
  4. 4A = 0, BC = 10
  5. 5A = 1, BC = 00
  6. 6A = 1, BC = 01
  7. 7A = 1, BC = 11
  8. 8A = 1, BC = 10
3.Medium
MUX0I0​CI1​0I2​1I3​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 = C, I₂ = 0, I₃ = 1. For how many of the 8 combinations of A, B and C is the output F = 1? Find N.

I₀ = 0I₁ = CI₂ = 0I₃ = 1
N =
4.Medium
ABC000111100101324576

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

F = A′B′ + A′BC′ + AC + AB′C
L =
5.Hard
CLKD12345678

A positive-edge-triggered D flip-flop starts with Q = 0 and receives the inputs shown at 8 rising clock edges. How many times N does Q change state?

Q₀ = 0D
N =
6.Hard
CLKD1234567

A positive-edge-triggered D flip-flop starts with Q = 0 and receives the inputs shown. Click the first clock edge at which Q goes from 1 back to 0.

Q₀ = 0D
  1. 1clock edge 1
  2. 2clock edge 2
  3. 3clock edge 3
  4. 4clock edge 4
  5. 5clock edge 5
  6. 6clock edge 6
  7. 7clock edge 7

Answer key

  1. 1. N = 4
  2. 2. A = 0, BC = 01
  3. 3. N = 3
  4. 4. L = 6
  5. 5. N = 4
  6. 6. clock edge 4

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