Transcript Home-made Speaker

Home-made Speaker
Group 5: Lau Pui Ying Cindy (8)
Sun Yik Ting Jessica (12)
Tsui Lok Lam Irene (13)
Reason why we make the speaker
 Understand the structure of a speaker
 Learn more about how it functions
 Physical theories
 Reusable
Expectations
 Clear Sound produced
 Adjustable Volume
 Separate basso and treble
 Special effect
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Theory
S
 Current passes through the coil
N
 Under B-field
 Fleming’s Left Hand Rule
 Magnetic force is produced
Theory
 a.c. flows through the
voice coil
 Coil's polar orientation
reverses
 Voice coil vibrates
 Diaphragm vibrates
 Sound is produced
1st Product
Improvements - Changes
 Coil – arranged more tidily
 Paper (on top) –
lighter paper is used
 Paper (on top) –
cardboard support
 Paper on top is pasted
more firmly
2nd Product (Renewed)
Demonstration
Difficulties
 Increase B-field  magnet ring
 Adjustable volume  variable resistor
 Amplitude  amplifier
N
S
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Reference
 Metacafe - Homemade SPEAKERS
http://www.metacafe.com/watch/719200/h
omemade_speakers/
 Metacafe - How to Make a Speaker
http://www.metacafe.com/watch/1541071/
how_to_make_a_speaker/
Question
&
Answer