Digital circuits for flip fops

how to use d flip flop in kicad 5.

You might want to provide a bit more information about what you want to achieve.

I want to use d flip for counters ,however I am unable to get correct waveform for d flip flop using any of the flip flops available in library.It would be helpful if you could post schematic of d flip flop schematic in kicad nightly builds along with waveform.


For designing pcbs (core function of kicad) there are symbols for such parts in the 74xx and cmos4000 libraries.

I don’t think kicad comes with spice models for such devices. So you will need to find them somewhere. I would guess the manufacturers of these are a good start to look at. (Assuming you want to simulate a real component. If you only want to simulate a d-flip flop then kicad might not be the right software for you. You could also look into qucs.)

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I am getting this waveform which is not correct.How should I correct my circuit?

We can’t see all of the output from the simulation but there are several errors that we can see, you need to fix them first.

And even then you won’t get any waveform as all your inputs are static.

these are the output errors.Please can you tell me how to fix this error.

You have a few symbols without a valid spice model.

Do those symbols still have hidden power pins? Or is there a power block somewhere?

“vdd” is not defined for U1 so it is not connected to the “VDD” voltage source.

The voltage sources do not seem to have any voltage specified.

Depends on the library version and on the exact symbol used. Some such symbols have been updated by @bobc not to use hidden power pins any longer. (But only for the version 5 libraries not the version 4 ones)

Please can you tell me the procedure on how to use d flip flop as I am not able to make it work correctly

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