On Mon, 19 Nov 2012 09:13:26 -0800, "bob" wrote:

I have a rechargeable vacuum cleaner from which I lost the power adapter a
long time ago. Now I found one (I think!) and it fits and everything, but
I'm not sure. The vacuum cleaner says "9.6V" but the adapter says "12.5V".
Is that an indication that it's the wrong adapter?

Depends on where on the vacuum cleaner it says 9.6V because it can be one of
two things:

It could be the voltage of the batteries inside. 8 Nicds would be 9.6V.
It could mean the input voltage of the charger.
You should be able to tell which of the above applies.

In the first case, a 12.5V adapter may be the right one.
In the second case, the adapter is definitely wrong.

One possible way to be sure is to find a product photo and look at the
adapter. Or find a product manual and check the specs.

Or find the same product in a store, and open the package, but only if
you can reseal it so it looks good.