Final answer:
A JK flip-flop is a type of digital circuit that can store a single bit of information. It changes its state based on input values J and K and the clock signal. A 4-bit synchronous counter can be created using four JK flip-flops and appropriate logic gates.
Step-by-step explanation:
A JK flip-flop is a type of digital circuit that can store a single bit of information. It has two inputs, J (set) and K (reset), and two outputs, Q (present state) and Q' (complement of present state). The flip-flop changes its state based on the inputs and the clock signal. When the input values J=1 and K=0, Q=1 and Q'=0, which is known as the 'set' condition. When J=0 and K=1, Q=0 and Q'=1, which is the 'reset' condition. When J=0 and K=0, the flip-flop maintains its previous state. When J=1 and K=1, the flip-flop toggles, that is, if Q was 1, it becomes 0, and vice versa.
A 4-bit synchronous counter can be created using four JK flip-flops. Each flip-flop is connected to the clock signal, and the outputs of the previous flip-flops are used as inputs for the next flip-flops. The clock signal synchronizes the operations of all the flip-flops, ensuring that they change their states at the same time. By using appropriate logic gates, the desired counting sequence can be achieved.