How do earphones work?

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c2

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I need help with my homework. We're supposed to explain how earphones work, using the simplest terms. I know it involves a coil of wire and a magnet and how the magnet vibrates with the sound but i can't quite explain it all myself. Any help would be appreciated.
-Thanks
 

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  • #2
drag
Science Advisor
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Greetings !

Welcome to PF c2 !

(Oops... I thought you were asking about
microphones so I started from one, I now
added the earphone part below.)
Well, in the simplest form like you asked, the
magnet moves at the frequency of the sound waves
and as it moves it creates an alternating
magnetic field. This amf forces the free electrons
in the coil to move back and forth as well which
in turn creates an alternating electric field in
the coil (and across the electric circuit), much
like a generator.

In an earphone, the same happens in reverse.
An alternating electric field (at the appropriate
frequency from a microphone or a recording) forces
the electrons in the coil to move back and
forth creating an amf round the coil. A magnet
inside the coil (that has its own magnetic field)
is affected by it and moves back and forth as well.
As the magnet does so it creates sound waves of
the required frequency in the air.

Live long and prosper.
 
Last edited:
  • #3
russ_watters
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5,872
Originally posted by c2
[?]
I need help with my homework. We're supposed to explain how earphones work, using the simplest terms. I know it involves a coil of wire and a magnet and how the magnet vibrates with the sound but i can't quite explain it all myself. Any help would be appreciated.
-Thanks
You just did explain it. Sound is a vibration. Coil makes the magnet (attached to the speaker) vibrate. Simple as that.
 
  • #4
Greetings !

Welcome to PF c2 !

(Oops... I thought you were asking about
microphones so I started from one, I now
added the earphone part below.)
Well, in the simplest form like you asked, the
magnet moves at the frequency of the sound waves
and as it moves it creates an alternating
magnetic field. This amf forces the free electrons
in the coil to move back and forth as well which
in turn creates an alternating electric field in
the coil (and across the electric circuit), much
like a generator.

In an earphone, the same happens in reverse.
An alternating electric field (at the appropriate
frequency from a microphone or a recording) forces
the electrons in the coil to move back and
forth creating an amf round the coil. A magnet
inside the coil (that has its own magnetic field)
is affected by it and moves back and forth as well.
As the magnet does so it creates sound waves of
the required frequency in the air.

Live long and prosper.
Can you give me an appropriate MLA for this information?
 

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