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 = 0B = 0C = 0N1G1G2G3F

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

A = 0B = 0C = 0
  1. 1N1
  2. 2G1
  3. 3G2
  4. 4G3
2.Easy
ABCF000?001?010?011?100?101?110?111?

The function F = (A ⊕ B) + A + C is 0 for exactly one combination of the inputs. Click that row of the truth table.

F = (A ⊕ B) + A + C
  1. 1ABC = 000
  2. 2ABC = 001
  3. 3ABC = 010
  4. 4ABC = 011
  5. 5ABC = 100
  6. 6ABC = 101
  7. 7ABC = 110
  8. 8ABC = 111
3.Medium
ABC00011110011011130204051716

Use the Karnaugh map to find the minimal sum-of-products (SOP) form of F(A, B, C) = Σm(0, 1, 3, 6, 7). How many product terms N does it have?

F(A, B, C) = Σm(0, 1, 3, 6, 7)
N =
4.Medium
ABCD000111100001111010011302040507061121130150141809011110

Use the Karnaugh map to find the minimal sum-of-products (SOP) form of F(A, B, C, D) = Σm(0, 3, 8, 10, 12, 13). How many literals L does it contain in total (a primed variable counts as one literal)?

F(A, B, C, D) = Σm(0, 3, 8, 10, 12, 13)
L =
5.Hard
TQ0​Q0​TQ1​Q1​TQ2​Q2​CLKUP

A 3-bit binary up counter starts at 1 (decimal, Q = 001). Which count Q (in decimal) does it show after 26 clock pulses?

Q0 = 126n = 3
Q =
6.Hard
TQ0​Q0​TQ1​Q1​TQ2​Q2​CLKUP

A 3-bit binary up counter starts at 1 (decimal, Q = 001). Which count Q (in decimal) does it show after 12 clock pulses?

Q0 = 112n = 3
Q =

Answer key

  1. 1. G1
  2. 2. ABC = 000
  3. 3. N = 3
  4. 4. L = 13
  5. 5. Q = 3
  6. 6. Q = 5

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