WORKING OF EAR PHONE OR HEADPHONE

Its working is quite similar to that of speakers. Here we don't need any amplifiers which we employ in case of speakers. We all might know that its just because we don't need to produce any big sound as we place it close to our ears and the sound produced is more than enough to hear to our favorite music. The earphone is a delicate thing which most people use daily to entertain them. Its kinda delicate structure and that's why more often we see that our earphone's get changed atleast once a year.

Well the earphone jack plays an important role in extracting different signals required for its smooth operation. A normal earphone jack (also called TRS connector) has three parts:

• TIP
• RING
• SLEEVE 

The below image will help you in understanding even better as to which positions of the jack are we referring to.

This TRS connector has three wires attached to it, one for the ground which is passed to both left and right earpiece, and other two are signal carrying wires to left and right earpiece respectively. Now hope everyone got it how is it that sometimes you hear to drum beats in one and simultaneously a different music in other,this is how it all happens, truly awesome.

Tip of the connector is connected to wire carrying audio equivalent electrical signals to left earpiece while the
Ring connects to the right earpiece and so the sleeve is obviously connected to the ground.

Each of three parts are insulated from one another which can be seen in above picture (here a black insulator separates them from one another). Actually the construction of this connector is as follows,
Firstly a thin rod is taken which has a bulged corner shown in image as TIP and over its rest narrow part an insulator is placed which is again covered by an hollow medium length cylindrical shaped conductor which is referred as SLEEVE. Over the top end of the sleeve which is narrower an insulator is again placed and surrounded finally by the next conductor called as RING.
The signal carrying wires carry signals to respective earpiece. Both the earpiece have same construction.
The below figure shows how the back connections of an earpiece, where both the wires are connected to the driver unit. This driver unit is in turn connected to the voice coil.

The above picture  shows an earpiece with its top rubbery hollow cover removed. Here we see a metallic plate  over which there comes a net(mesh) covering which prevents unwanted material or dust from entering into the working bottom of the earphone as it could cause an unwanted change in the working of the earpiece and thereby annoy us. The voice coil and the diaphragm is shown. Diaphragm used here is a very thin plastic film and attached to it is the voice coil (copper coil wound with certain number of turns). This copper coil is placed in a region where it surrounds the permanent magnet. When electrical signal pass through the device to the earpiece through signal carrying wires, it is passed on to the voice coil. since these electrical signal is varying proportional to the audio it causes a current flow through the voice coil to be changing accordingly and since we know that a current carrying conductor produces magnetic field there results a varying magnetic field  due to varying current. Since there is a permanent magnet which has its magnetic field around now gets into interaction with the magnetic field created by the voice coil results into a force of attraction or repulsion depending on the current flow in the voice coil, and hence this varying force causes diaphragm attached to the voice coil to vibrate accordingly disturbing the air particles closer to it . This variation then propagates to our ears and gets sensed by the eardrum. So this is how a earphone works!! 

CONTRIBUTION:

Jaseem Ahamed

NMAMIT NITTE

YOU CAN CONTRIBUTE ARTICLES BY SENDING YOUR ARTICLE TO harimdg@gmail.com