hi all,

I just bought a new gadget (a cheap IP camera) the plug/psu of which
makes a faint high pitched whining noise when connected to the wall
socket - UNTIL I connect the other end to the camera (camera works
fine by the way). Then the noise stops.

When I plugged it in at the socket, the wall the socket was already
switched "on" and there was a little bit of a spark I think... I have
seen this occasionally before (I have no idea if the psu was totally
silent before this or if its a factor)

Also I noted that the "top" prong of the plug (UK plug) was plastic?
I.e. no earth. Could this cause the small spark I saw?

What might this noise be and should I worry?

thanks guys!