# What is a Race-Around Condition? Explain JK Flip-Flop.?

Please provide the details of a Race Around Condition. Explain the phenomenon of a JK Flip Flop?

05-11-2012

06-11-2012
"A flip-flop is a bistable device, i.e. it has two states. Its output remains either high or low. The high state is 1 called SET and the low state is 0 called RESET. The JK flip flop is the most versatile flip-flop, and the most commonly used flip flop when discrete devices are used to implement arbitrary state machines. Like the RS flip-flop, it has two data inputs, J and K, and a clock input. It has no undefined states or race condition, however. It is always edge triggered; normally on the falling edge. The JK flip-flop has the following characteristics: i) If one input (J or K) is at logic 0, and the other is at logic 1, then the output is set or reset (by J and K respectively), just like the RS flip-flop, but on the (falling) clock edge. ii) If both inputs are 0, then it remains in the same state as it was before the clock pulse occurred; again like the RS flip flop. iii) If both inputs are high, however the flip-flop changes state whenever the (falling) edge of a clock pulse occurs; i.e., the clock pulse toggles the flipflop. There are two basic types of JK flip-flops. The first type is basically an RS flipflop with its outputs and ANDed together with J and K respectively. This type of JK flip-flop has no special name. Note that the connection between the outputs and the inputs to the AND gates determines the input conditions to R and S when J = K = 1. This connection is what causes the toggling, and eliminates the invalid condition which occurs in the RS flip flop. The second type of JK flipflop is called a master-slave flip flop. This consists of two RS flip flops arranged so that when the clock pulse enables the first, or master latch, it disables the second, or slave latch. When the clock changes state again (i.e., on its falling edge) the output of the master latch is transferred to the slave latch. Again, toggling is accomplished by the connection of the output with the input AND gates. The JK flip-flop is a very versatile device, and is probably the most commonly used form of flip-flop in digital electronic and control circuits. The fact that it has two inputs often means that it is simpler to design the control logic required to ensure that it changes state properly in a circuit. Source: http://in.docsity.com/en-docs/Fundamentals_of_Information_Technology__Lecture_Notes__Elveera_Miranda"
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06-11-2012
"in simple jk flip flor circuit at condition j=1 and k=1 every time output toggle w.r.t previous output,we use single clock in this case so that condition known as race around condition.by using master slave jk flip flop we can remove this problem"
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