I am not a Electronic Engineer, so probably any expert out there can correct me if I am thinking wrong.
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The JK flip-flop augments the behavior of the SR flip-flop by interpreting the S = R = 1 condition as a "flip" or toggle command. Specifically, the combination J = 1, K = 0 is a command to set the flip-flop; the combination J = 0, K = 1 is a command to reset the flip-flop; and the combination J = K = 1 is a command to toggle the flip-flop, i.e., change its output to the logical complement of its current value. Setting J = K = 0 does NOT result in a D flip-flop, but rather, will hold the current state. To synthesize a D flip-flop, simply set K equal to the complement of J. The JK flip-flop is therefore a universal flip-flop, because it can be configured to work as an SR flip-flop, a D flip-flop or a T flip-flop. NOTE: The flip flop is positive edge triggered (Clock Pulse) as seen in the timing diagram.
and the corresponding truth table is:
Figure 1. A Simple Ripple Counter Consisting of J-K Flip-flops
Method1: You will find answer here: http://www2.cs.uh.edu/~jhuang/JCH/LD/chap07.html
Here you see how to create ripple counter using RS flip flop.
Method 2: create a Toggle function in RS flip flop, then use it in place of typical jk flip flop ripple couters.