Q.1) Explain J-K flip flop.
Answer) The J-K flip-flop is the most versatile of the basic flip-flops. It has the input- following character of the clocked D flip-flop but has two inputs,traditionally labeled J and K.
S = not(K.Q)
R = not(J.not(Q))
Analyzing the above circuit :
I) When CLK = ↓, J = 0, K = 1,
The output of the flip-flop does not change, i.e. Q and not(Q) retain their state.
II) When CLK = ↑ , J = 0, K = 0
S = 1; R = 1,
Outputs will be retained.
III) When CLK = ↑ , J = 0, K = 1
S = not(Q) ; R = 1, hence according to the operation of S-R latch,
Q = 0 and not(Q) = 1.
IV) When CLK = ↑ , J = 1, K = 0
S = 1; R = Q, hence according to the operation of S-R latch,
Q = 1 and not(Q) = 0.
V) When CLK = ↑ , J = 1, K = 1
S = not(Q), R = Q
a) If Q = 0 and not(Q) = 1,
S = 1 and R = 0, hence output Q = 1 and not(Q) = 0.
b) If Q = 1 and not(Q) = 0,
S = 0 and R = 1, hence output Q = 0 and not(Q) = 1.
Hence, we conclude that for J=K=1, the outputs get toggled.
a) When Q retains state '0' ,
J = K = 0 and J = 0 , K =1 => J = '0' , K = 'x'
b) When Q changes from '0' to '1' ,
J = K = 1 and J = 1 , K =0 => J = '1' , K = 'x'
c) When Q changes from '1' to '0' ,
J = K = 1 and J = 0 , K =1 => J = 'x' , K = '1'
d) When Q retains state '1' ,
J = K = 0 and J = 1 , K =0 => J = 'x' , K = '0'
Excitation Table for J-K Flip Flop.
Flop to be derived : J-K flip flop (Input)
MUST READ : S-R flip flop
![K map simplification for R](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi0fzQ4ABKBm0IqHYww3bzGV4QYdcXSe3y5SHSzvws7TnZesAaikowdKOh3OPldwy4Dy-C9qOno4qiGVGZrMbYPRzOvQp-uNqmtn2Uh9_BPVesbio4X5FCWtcNVQsMZomBU3UQRRRPazNn_/s1600/r_jk_kmap.jpg)
Flop to be derived : D flip flop (Input)
MUST READ : D flip flop
![K map simplification for D](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgqdvc9X-KkbV2qJsk0uIs0Hq6S5QeQHWAoqrBwGmVzq9eFUM3_xGTRp54V9Oyg91mhRXa2waQJ2lJn_8mly1ZPFrmkAYkItT4N_b3msO2MSXhMFNO9INSStNXkZb8XbDxDYC2rCCGmzvtR/s1600/k_d_kmap.jpg)
Truth Table for J-K Flip Flop.
Q.2) Draw the excitation table for J-K flip flop.
Answer) From the truth table, we can infer the following points :a) When Q retains state '0' ,
J = K = 0 and J = 0 , K =1 => J = '0' , K = 'x'
b) When Q changes from '0' to '1' ,
J = K = 1 and J = 1 , K =0 => J = '1' , K = 'x'
c) When Q changes from '1' to '0' ,
J = K = 1 and J = 0 , K =1 => J = 'x' , K = '1'
d) When Q retains state '1' ,
J = K = 0 and J = 1 , K =0 => J = 'x' , K = '0'
Excitation Table for J-K Flip Flop.
Q.3) Convert S-R flip flop into J-K flip flop.
Answer) Given flop : S-R flip flop (Output)Flop to be derived : J-K flip flop (Input)
MUST READ : S-R flip flop
Combined truth table for converting S-R flip flop into J-K flip flop.
![K map simplification for S](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgxzYEfJ7-8worqYmcxMl22lMk7qLEzsHHdB6gjpcs8UL6yRawWJGmsGjx9uxeihVYVkiEnxD3urWTgXGTAkAeyoS4Om-YULjnY7HWr851elHHMrwM0u6B_yg-uK6erWKhC4Joa7tL4h9na/s1600/s_jk_kmap.jpg)
![K map simplification for R](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi0fzQ4ABKBm0IqHYww3bzGV4QYdcXSe3y5SHSzvws7TnZesAaikowdKOh3OPldwy4Dy-C9qOno4qiGVGZrMbYPRzOvQp-uNqmtn2Uh9_BPVesbio4X5FCWtcNVQsMZomBU3UQRRRPazNn_/s1600/r_jk_kmap.jpg)
K-Map Simplification
J-K flip flop using S-R flip flop.
Q.4) Convert J-K flip flop into D flip flop.
Answer) Given flop : J-K flip flop (Output)Flop to be derived : D flip flop (Input)
MUST READ : D flip flop
Combined truth table for converting J-K flip flop into D flip flop.
![K map simplification for J](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhOUIzgxIMX_vM3WYYX__EGsCPSe2zfma-LLWrAVRUk4y1jui4Pyl27vr57pe0lTrMwu7VHV3t61h9eH16XOZa9f04_tHXG7xTFSn8VCwFzdgCEejx3L_C3HqmwxVeNqj1VmTcYr-xy3Sg0/s1600/j_d_kmap.jpg)
![K map simplification for D](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgqdvc9X-KkbV2qJsk0uIs0Hq6S5QeQHWAoqrBwGmVzq9eFUM3_xGTRp54V9Oyg91mhRXa2waQJ2lJn_8mly1ZPFrmkAYkItT4N_b3msO2MSXhMFNO9INSStNXkZb8XbDxDYC2rCCGmzvtR/s1600/k_d_kmap.jpg)
K-Map Simplification
D flip flop using J-K flip flop.
Q.5) Convert J-K flip flop into S-R flip flop.
Answer) Given flop : J-K flip flop (Output)
Flop to be derived : S-R flip flop (Input)
Combined truth table for conversion of J-K flip flop into S-R flip flop.
K-Map Simplification
S-R flip flop using J-K flip flop.
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