What is a frequency counter and how does it work

[abhishek002]

frequency counters has got an influence upon me
i would like to know how it works
and if possible how to make one

 

[Bobbywhy]

For a fairly good introduction to frequency counters see this Wiki page:
http://en.wikipedia.org/wiki/Frequency_counter

You-build-it frequency counter kits, starting at $29.95:
http://www.google.com/#q=frequency+....,cf.osb&fp=83ec0cc01db0c140&biw=1366&bih=683