Continue to Site

Welcome to

Welcome to our site! is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

How will D flip-flop output depend on clock?

Not open for further replies.


Member level 4
Aug 19, 2007
Reaction score
Trophy points
Activity points
Dear friends,

I have two D flip flop with Q1 as output of First F/F and Q2 of second F/F

i have given D as 1

What will be the output Q1 and Q2 depaending on Clock

Pls explain


Re: about flip flop

After 2 clock cycles, the output of 2nd flipflop will be 1. At the end of first clock cycle, the 1 at D will be available at q of the first flop and this 1 will be captured by the 2nd flipflop at the second cycle and will be available at q of the second flipflop.
The value at q of the second flipflop during the first clock cycle is an invalid value or a value that should not be used in any other logic. This is the basis of pipelining.
Please do correct me if I am wrong.


Re: about flip flop

Dear dude,

My clock is a pulse train which has postivie and neagtive cycle.

Now on positive cycle first F/F will give Q as 1,
Then the neagtive cycle comes now what will be condition or Q1 and Q2


about flip flop

FF is edge triggered. so clock active edge will be either +ve or - ve. If the FF is +ve edge triggered. then for first +ve edge output Q1 will be one and Q2 will be at its previous state. At -ve edge the outputs Q1 & Q2 will be maintained as it is. At second +ve clock edge Q1 will be D (depending on input D) and Q2 will be 1.

Re: about flip flop

During the negative clock cycle, FF1 would continue to store 1 which it had latched during the positive cycle and FF2 would now hold the value that was previously held by FF1. Am I missing some condition here?.

Not open for further replies.

Part and Inventory Search

Welcome to