The document discusses various types of flip-flops used in digital circuits, including D flip-flops, JK flip-flops, and T flip-flops, highlighting their operations and characteristics. It explains synchronization issues with latches and proposes using flip-flops that respond at specific times. Additionally, it details the operations each flip-flop type can perform and their configurations using different inputs.

1. Flip Flops
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26. Flip-Flops
• Latches are “transparent” (=> any change
on the inputs is seen at the outputs
immediately).
• This causes synchronization problems!
• Solution: use latches to create flip-flops that
can respond (update) ONLY at SPECIFIC
times (instead of ANY time).

27. D FLIP-FLOP

32. Flip flop can perform 3 operations
• Set the output to 1
• Reset the output to 0
• Complement the output
• D flip-flop can perform first two operations.

33. JK Flipflop
Characteristics Equation : D = JQ’ + K’Q
J=K=0; No Change
J=1,K=0, D=1, so Q = 1
J=0,K=1, D=0, so Q = 0
J=K=1, D= Q’, so Q = Q’
•It can perform all three operations.
•It has two inputs and a clock signal.
•It makes use of D flip-flop.

35. T (toggle) Flip-flop
• It’s a complementing flip-flop
• It can be made using JK flip-flop or D flip-
flop.
• If made using JK flip-flop
– Inputs J & K are tied together
– T=0, J=K=0, No Change in Q
– T=1, J=K=1, Q = Q’
• If made using D flip-flop
– Q = D = T XOR Q = TQ’ + T’Q

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