Q- Design MOD-3 ripple counter using (a) Observing outputs (b) K-maps to design the circuit. Ans: (a)We can design the MOD 3 counter using 2 FFs as 3 is less than 4 i.e. 22 and greater than 2. We can see directly that as we have to reset the counter only after 2 i.e. when output is […]
Digital Electronics
Counter other than MOD-2n
Q-Can we design a ripple counter other than MOD-2n? Ans: Yes we can. For this we’ll first design the counter with value which is multiple of 2 but greater than the count required. Then we use a combinational circuit to reset the counter after the required value of count is achieved. Let’s take an example: Design […]
Ripple counter
We can attach more flip-flops to make larger counter. We just use more flip-flops in cascade and give output of first to the clock of 2nd and output of 2nd to clock of 3rd and so on. This way every flip-flop would divide frequency of the clock by 2 and hence we can obtain a divide by larger […]
Asynchronous Counters: MOD-2 counter
If we see that flip-flop is a mod-2 counter with starting count as 0. If we connect J & K to HIGH and supply clock to the flip-flop, we’ll see that flip-flop would count pulses 0, then 1 and as it is a MOD-2 counter so it’ll reset and again count from 0. And the […]
Q: Serial Data Transfer
Q- Design a circuit to transfer data serially from one shift register to other. Ans: If we have a N-bit shift register then we need only N clock cycles to shift those N-bits to the other register. If we apply more or less than this many clock cycles then our operation of shifting would not […]
Johnson Counter
While Ring counter, we have connected Q of last to D of 1st FF, but in Johnson Counter we connect Q bar of last to D of 1st FF as shown below and we also don’t need to connect preset of 1st FF. This is also called Twisted Ring counter: And JK implementation is as follow: And we have […]
Ring counter
This is a special type of register in which 1 moves in the output in the ring i.e. initially output of 1st FF is 1. On next edge this 1 is transferred to output of 2nd FF while previous output becomes 0. Similarly on next clock output of 3rd FF becomes 1. Similarly it continuous till last FF […]
Shift register
In this type of register value stored in the register can be either shifted to left or right depending upon the circuit as: PARALLEL IN PARALLEL OUT: This type of shift registers is already discussed above. SERIAL IN SERIAL OUT: Right shift: Here data is shifted by one bit from left to right with every clock […]
Registers
A register is a group of 1- bit memory cells. To make a N-bit register we need N 1-bit memory cells. Register with parallel load: We can represent a simple 4-bit register as: We can give the values to be stored at input and we get that value stored at the next clock pulse. But […]
Flip flop = 1 bit Memory
1-bit Memory Cell: We know that flip-flop can store either zero or one permanently until a change is made in the inputs. Hence flip-flop would work as 1-bit memory cell.