Well in sequential circuits, paths exit between latches through combinational circuits from one latch to other or from output of latch to input of same latch. When we give a feed back to input of same latch then we face a timing problem as shown: Suppose we have the following circuit: In this circuit when […]
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T Latch
This latch is obtained from JK by connecting both the inputs. This is also known as Toggle latch as output is toggled if T=1. The truth table is: The circuit diagram of T latch is as follow:
JK Latch
This is very similar to RS latch but the ambiguous state has been eliminated and output is fed back to the AND gates. Also in this latch we get a complimented output when both the inputs are 1. Inputs are designated as J and K. The circuit diagram is as follow: Let’s now try to […]
D Latch
As we have already discussed that when ever we have both R & S equal to 1 we witness an ambiguous state. Hence to avoid this we have made an arrangement in which we’ll never have both R & S equal. We connect the two inputs with an inverter between them as shown below: This […]
Clocking RS latch
We can control RS Latch with clock by ANDing both inputs with clock separately as: Hence when we have CLK (OR E) = 1, R & S gets passed to the RS latch circuit and hence the output is affected by the inputs only when CLK (OR E) = 1 and when CLK (OR E)=0, […]
RS Flip flop implementation(NAND gates)
We can also represent the above circuit using NAND gates as: Let’s convert to NAND circuit step by step. R’S’ FLIPFLOP The characteristics of the FF are as given in table: Now we replace R by R (bar) and S by S (bar) and eliminating the 2 circles and hence final circuit.
RS Flip flop
When R=0, S=0 we don’t have a change in the output in the circuit. When R=0, S=1 we have output as Q=1 and Q bar = 0 When R=1, S=0 we have the output as Q=0 and Q bar = 1 But when we have R=1, S=1, both R and S make outputs of their […]
Deriving the circuit of Flip flop
DERIVING THE CIRCUIT OF FLIPFLOP (from digital components): To understand the logic let’s consider a basic circuit of an inverter with a feedback as below: Now what would be the output of the circuit? We know what ever is at input, we’ll get inverse of that at output and as output is fed back to input […]
Bistable Multivibrator/Flip flop
FLIP-FLOP is another name of Bi-stable Multi-vibrator. A flip-flop is the basic element of sequential circuit. It has the capability of storing 1 bit. The circuit of the Bi-stable Multi- vibrator using transistors is as follow: The two transistors are used to store a single bit and they can hold data without external assistance as far as power is […]
Clock
A clock signal is defined by clock period or clock frequency. The clock period is defined as time interval after which clock repeats it self or we can define it as time gap between two consecutive falling edges or two consecutive rising edges and clock frequency is defined as number of clock pulses in a second. Clock […]