Apparatus :
Digital Trainer kit, single strand wires, breadboard, NAND gates ICs- 7400, NOR gates ICs-7402, Flip-flop ICs- 7476
THEORY:
RS FLIP-FLOP: There are two inputs to the flip-flop defined as R and S. When I/Ps R = 0 and S = 0 then O/P remains unchanged. When I/Ps R = 0 and S = 1 the flip-flop is switches to the stable state where O/P is 1 i.e. SET. The I/P condition is R = 1 and S = 0 the flip-flop is switched to the stable state where O/P is 0 i.e. RESET. The I/P condition is R = 1 and S = 1 the flip-flop is switched to the stable state where O/P is forbidden.
• JK FLIP-FLOP: For purpose of counting, the JK flip-flop is the ideal
element to use. The variable J and K are called control I/Ps because they determine what the flip- flop does when a positive edge arrives. When J and K are both 0s, both AND gates are disabled and Q retains its last value.
• D FLIP –FLOP: This kind of flip flop prevents the value of D from reaching the Q output until clock pulses occur. When the clock is low, both AND gates are disabled D can change value without affecting the value of Q. On the other hand, when the clock is high, both AND gates are enabled. In this case, Q is forced to equal the value of D. When the clock again goes low, Q retains or stores the last value of D. a D flip flop is a bistable circuit whose D input is transferred to the output after a clock pulse is received.
• T FLIP-FLOP: The T or "toggle" flip-flop changes its output on each clock edge, giving an output which is half the frequency of the signal to the T input. It is useful for constructing binary counters, frequency dividers, and general binary addition devices. It can be made from a J-K flip-flop by tying both of its inputs high.
Conversion of JK flip flop to D flip flop
D is the external input and J and K are the actual inputs of the flip flop. D and Qp make four combinations. J and K are expressed in terms of D and Qp. The four combination conversion table, the K-maps for J and K in terms of D and Qp, and the logic diagram showing the conversion from JK to D are given below.
Conversion of JK flip flop to T flip flop
J and K are the actual inputs of the flip flop and T is taken as the external input for conversion. Four combinations are produced with T and Qp. J and K are expressed in terms of T and Qp. The conversion table, K-maps, and the logic diagram are given below.
PROCEDURE:
1. Connect the circuit as shown in figure.
2. Apply Vcc & ground signal to every IC.
3. Observe the input & output according to the truth table.
0 Comments