I am a senior industrial design major and I am have been asked to give
a brief presentation on RFID tags and how they work. I understand the
general concept but I am not sure the specific technical aspects of
the system. I was wondering if someone could explain the basic
principle of how these tags work (in layman's terms!) I have
conducted some research but I am not sure I completely understand the
difference between active, passive and semi active. Another thing I
am a little confused with is that I read that they are used in
library's and theft deterrent devices in retail. I have taken some of
these tags apart (specifically the ones found in CD's ) and it appears
they are a plastic housing with thin sheets of steel in them. Are
these considered RFID or strictly magnetic detectors that must be
demagnetized in order to pass through the detector. If anyone can
shed some light on this issue, I would be most appreciative. Thank you
very much.

Sincerely,

Jesse Stein