A JK flipflop is a refinement of the SR flipflop, in which the indeterminate state of the SR type is defined in the JK type. Inputs J and K behave like inputs S and R to set and clear the flipflop (note that in a JK flipflop, the letter J is for set and the letter K is for clear). When logic 1 inputs are applied to both J and K simultaneously, the flip-flop switches to its complement state, ie., if Q=1, it switches to Q=0 and vice versa. Logic symbol of JK Flipflop A clocked JK flip-flop is shown in Figure. Output Q is ANDed with K and CP input so that the flipflop is cleared during a clock pulse only if Q was previously 1. Similarly, output Q' is ANDed with J and CP input so that the flip-flop is set with a clock pulse only if Q' was previously 1. Note that because of the feedback connection in the JK flipflop, a CP signal which remains a 1 (while J=K=1) after the outputs have been complemented once will cause repeated and continuous transitions of the outputs. To av
Figure shows the logic circuit of T flipflop in which J and K inputs of a JK flip flop are combined and taken as a single input T. When T = 0, output of T flipflop will remain as it was previously. When T = 1, output of T flipflop will be complement of its previous output and hence this circuit is known as toggle circuit. Logic symbol of T Flipflop Logic Diagram of T Flipflop Q T Q(t+1) 0 0 0 1 0 1 0 1 1 1 1 0 Transition table of T flipflop
The D flip-flop shown in Figure is a modification of the clocked SR flip-flop. The D input goes directly into the S input and the complement of the D input goes to the R input. The D input is sampled during the occurrence of a clock pulse. If it is 1, the flip-flop is switched to the set state (unless it was already set). If it is 0, the flip-flop switches to the clear state. Logic Symbol of D Flipflop Logic diagram of D Flipflop Q D Q(t+1) 0 0 0 0 1 1 1 0 0 1 1 1 Transition Truth table of D Flipflop
Comments
Post a Comment