hey everyone
i need help to make a digital tachometer.
can anyone suggest me a circuit diagram or logic for it.
waiting for help.

 

Is this homework help? Do you need to design it or build it too? Is it for a real world application?

 

I assume by digital tachometer you mean you would like to see the results displayed as numeric digits.

There is another name for this - "frequency counter".

 

yes right.
can anyone tell me how to make it?

 

Have you tried Google and say something like tachometer circuit? We do not mind helping students in this forum. But we do not just hand out some ready solution on a silver plate. As that would be cheating.
Also good questions draw good answers. You have to tell us more about your project. Like do you have to use some type of circuits