When i plug a mic into my canon hg10, it just buzzes in playback

I reacently purchased the canon hg10

i am VERY happy with it.

But i came acrost a problem when tring to plug a cheap mic into the mic terminal.

i tried it again with anothor cheap mic and it was the same.

All it made when i played it back was a loud BUZZZZZ

i have a new shotgun mic coming in the mail and hope that will make a difference

if anyone with any experience with canon cameras has any idea on what i could try, that will be greatly appreciated

thank you

-Films inc Media