"Steve Barker" wrote in message

fyi, the transformer should come with the doorbell unit.

Where do you buy your doorbells? I've never seen one come with a
transformer.

No here that a transformer is required, not included
http://www.dimango.com/dc-hardwired-doorbells.htm

Accessories:
Transformer (Not Included, Uses 16v)
Buttons (As needed)