hi,
i m kapil and i have to make a digital tachometer (to measure in rpm),and the obligations to my project is that, that i can only use 7--- and 4--- series ICs (without a MC or uC). And its gapping time should be 0.1s (can measure around 400rpm).Can anyone help me out...plzzzz

thanking you,
kapzan

 

What is generating your indicator pulse? And how do you plan to display the result? What is your power source?

Is this a homework project?