Physics Demo Number: 204
Approximate
Run Time: 5 min
Transformer Coupling to Send Sound WavesÂ
Demo Description
 Two coils borrowed from elementary lab equipment, along with their magnetic  core attachment , are used to send music  froma computer or i-phone to the lecture hall interface with no hard-wired connection.
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Scientific Principles
 Transformers used to  wirelessly couple sound to lecture hall interface.
Equipment
 Stored in box with demo(175) on [B-3-4].Â
Equipment Location
[B-3-4]Instructions
 The
photo shows  the left hand transformer coil  ready to
receive the wireless wave from  the transformer coil on the right.
The left transformer coil has a double banana plug coupled to a BNC cable that terminates in a phono plug for entry into the lecture hall interface by way of  a  [CVBS or S-Video Â
+R/L to HDMI ] interface , seen in the last two photos.
In the right transformer coil one inputs  the electrical signal from the  music source with the appropriate adapters.
Using the iron linear frame from the coil set one may show the improved coupling of the signal over the air-core-coupling case.
