The relay its self buzzes, i had one on my desk a few weeks ago i was fiddling with so i decided to take it to bits, there is an electromagnetic coil, a reed thingy that vibrates, and a casing, the reed vibrates against a section of the case... thus making a BuZZZZZZZZZZZ Noise. I hooked it up to my power supply.. i entertained my self for hours with the little buzzy part of it i cant se anything else inside that looks like a relay though, just a coil and a reed
