Digital Electronics - Flip-Flops - Discussion

When j=k=1 the output toggles more than once for a single clock pulse. This phenomena is called racing in a jk flip flop. In question j=k=1 and output must toggle for more than once. So any frequency less than 20khz is correct 20khz is principle value.

As ff has 2 states I think 20/2=10khz is correct and toggling continuously from 0 to 1 makes a square wave and so it will be a square wave of <20khz. To eliminate this racing the pulse width of flip flop must be greater than propagation delay.

The flip flop is sensitive only to the positive or negative edge of the clock pulse. So, the flip-flop toggles whenever the clock is falling/rising at edge. This triggering of flip-flop during the transition state, is known as Edge-triggered flip-flop. Thus, the output curve has a time period twice that of the clock. Frequency is inversely related to time period and hence frequency gets halved.

@samiksha: because the flip flop is sensitive only to the positive or negative edge of the clock pulse....so the flip-flop toggles whenever the clock's falling/rising edge...thus the output curve has a time period twice that of the clock....frequency is inversely related to time period...and hence frequency gets halved.....got it??

Here, there is no mention of master-slave jk flip-flop (has 2 flip-flops ), its just jk flip-flop(just 1 flip-flop) so therefore, there is only one flip-flop.

O/p freq = i/p freq /2^n ; n=1.
= 20 / 2 = 10 Hz.

O/p frequency = i/p freq / 2^n ; where n is the number of F/Fs used.

Jk flip-flop has 2 flipflop s master and slave so according to that,

Op freq = 20 / 2^1 ; 2^ (n-1) < n > 2^n.

= 10 Hz.

j=0 , k=0------------> No change state.
j=1 , k=0------------> Set condition means output = 1.
j=0 , k=1------------> Reset condition means output = 0.
j=1 , k=1 -----------> Toggle.

@Satyapriya is rightly said when the j-k flip flop has two internal flip flop one is master and another one is slave so the output frequency can be achieve half frequency of the input.

As one flip flop is used so there is 2 states available.so 20/2=10hz frequency avail; able at the output. Am i right or wrong please someone replay.

When J = 1 and K = 1 outputs of JK flip flop are:

A) Qn+1=0
B) Qn+1=1
C) Qn+1=Q
D) Qn+1=Q\'

Give me the answer of this question.

@Tulasiram:

j= 0,k=0------->previous o/p.
j= 0,k=1--------->0.
j=1 ,k=0---------->1.
j= 1,k=1---------->toggle.