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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Name: ____________________   Date: ____________

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

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

F = (B′·C′)·A′
  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
ABC0001111001

Click the cell of the 3-variable Karnaugh map that belongs to minterm m6 (variables A, B, C with A the most significant bit).

m6
  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
MUXCI0​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 = C, 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 = CI₁ = CI₂ = 0I₃ = 1
N =
4.Medium
MUX0I0​C′I1​C′I2​C′I3​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 = C′, I₃ = C′. For how many of the 8 combinations of A, B and C is the output F = 1? Find N.

I₀ = 0I₁ = C′I₂ = C′I₃ = C′
N =
5.Hard
CLKT1234567

A positive-edge-triggered T 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 = 0T
N =
6.Hard
DQ3​Q3​DQ2​Q2​DQ1​Q1​DQ0​Q0​CLKJOHNSON

A 4-bit Johnson counter Q₃Q₂Q₁Q₀ starts at 0000. At every clock edge the bits shift one place to the right (Q₃ → Q₂ → Q₁ → Q₀) and Q₃ receives the inverse of Q₀. Give the state Q = Q₃Q₂Q₁Q₀ as a decimal number after 10 clock edges.

Q₃Q₂Q₁Q₀ = 000010
Q =

Answer key

  1. 1. ABC = 000
  2. 2. A = 1, BC = 10
  3. 3. N = 4
  4. 4. N = 3
  5. 5. N = 5
  6. 6. Q = 12

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