In our school library, there is a depository area wherein you deposit your
At 09:52 PM 7/12/96 +0800, you wrote: things and get the tag. Since the library doesn't allow those tags to be brought out from the library, everytime you brought it out and pass by the door, it will alarm. Does anyone know what stuff is that? How come it is alarmed? I brought some metals but it wouldn't alarm... Why those tag would alarm them???
Most of these systems are made of an oszillator (basically a few windings of a wire with a capacitor: ------ / \ Š--ŠŠ--Š \ / ------ This acts like an ordinary RLC-Oszillator. When you put it in a electrical field with the right frequency, it will effect the field strong enough to be detectable. So, if you shield it, you win. ----------< fate favors the prepared mind >---------- Remo Pini Fon 1: +41 1 350 28 82 mailto:rp@rpini.com Fon 2: +41 1 465 31 90 http://www.rpini.com/remopini/ Fax: +41 1 350 28 84 --------< words are what reality is made of >--------