Design a counter with the following binary sequence: 0, 4, 2, 1, 6 and repeat. Use JK flip-flops.

ANS: Counter with JK Flip-Flops for Binary Sequence: 0, 4, 2, 1, 6

Here’s the design for a counter with the sequence 0, 4, 2, 1, 6, using JK flip-flops:

Components:

  • Three JK flip-flops: JKA, JKB, JKC
  • Combinational logic circuit

Circuit Diagram:

CLK ----\
       |
       |   JKA
       |  / \
       | /   \
       |/     \
CLK ----      D
       |   -----
       |   |
       |   |  JKB
       |   | / \
       |   |/   \
       |   /     \
D -----     D
       |   -----
       |   |
       |   |  JKC
       |   | / \
       |   |/   \
       |   /     \
D -----     D
/---------+------+------\
          | QKA |   QKB |
          | QKC |
          \/---\/---\

Combinational Logic Circuit:

The combinational logic circuit generates the J and K inputs for each JK flip-flop based on the current state (QKA, QKB, QKC) and the desired sequence.

Truth Table:

QKAQKBQKCJKAJKBJKCNext State
0001xx0
00111x0
010x111
110xx11
10011x0

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Explanation:

  • JKA: When the current state is 000, JKA is set to 1 to ensure a transition to 001 on the next clock pulse.
  • JKB: When the current state is 001, JKB is set to 1 to ensure a transition to 010. When the current state is 010, JKB is set to 1 and JKC is set to 1 to ensure a transition to 110.
  • JKC: When the current state is 110, JKC is set to 1 to ensure a transition to 100. When the current state is 100, JKC is set to 1 to ensure a transition to 000.

Implementation:

The combinational logic circuit can be implemented using various logic gates (AND, OR, NOT) based on the desired truth table.

Note: This is a basic design for the counter. Additional logic can be added to implement features like reset, count enable, and output decoding.

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