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: 2 nsG18 nsG24 nsG36 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: 2 nsG1: 8 nsG2: 4 nsG3: 6 ns
tpd = ns
2.Easy
A = 0B = 1C = 0N1G1N2G2F

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

A = 0B = 1C = 0
  1. 1N1
  2. 2N2
  3. 3G1
  4. 4G2
3.Medium
ABCD000111100001111010011302141507060121131150140809011110

Use the Karnaugh map to find the minimal sum-of-products (SOP) form of F(A, B, C, D) = Σm(0, 3, 4, 5, 10, 13, 15). How many literals L does it contain in total (a primed variable counts as one literal)?

F(A, B, C, D) = Σm(0, 3, 4, 5, 10, 13, 15)
L =
4.Medium
ABCD000111100001111000010312140507060121131151140819011010

Use the Karnaugh map to find the minimal sum-of-products (SOP) form of F(A, B, C, D) = Σm(2, 4, 9, 13, 14, 15). How many literals L does it contain in total (a primed variable counts as one literal)?

F(A, B, C, D) = Σm(2, 4, 9, 13, 14, 15)
L =
5.Hard
TQ0​Q0​TQ1​Q1​TQ2​Q2​TQ3​Q3​CLKUP

A 4-bit binary up counter starts at 11 (decimal, Q = 1011). Which count Q (in decimal) does it show after 33 clock pulses?

Q0 = 1133n = 4
Q =
6.Hard
ABCD000111100001111010110302X4051706112013015X141819111110

Find the minimal SOP form of F(A, B, C, D) = Σm(0, 1, 7, 8, 9, 10, 11, 12) + d(4, 14), where d marks the don't-care conditions. How many product terms N does it have?

F(A, B, C, D) = Σm(0, 1, 7, 8, 9, 10, 11, 12) + d(4, 14)
N =

Answer key

  1. 1. tpd = 16 ns
  2. 2. G1
  3. 3. L = 17
  4. 4. L = 14
  5. 5. Q = 12
  6. 6. N = 4

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