How those little things convert mains AC to safe low voltage DC
http://www.howstuffworks.com/inside-transformer.htm
A method to determine the Linear Transformer Model parameters of a Neon Sign Transformer
http://hot-streamer.com/TeslaCoils/OtherPapers/TeroRanta/CurrentLimitedTransformers/NSTModel.htm
How to test that transformer.
http://home.earthlink.net/~jimlux/hv/xfmrmeas.htm