information Answered

what is voice coil?

It is the fine wire coil around the magnet with extremely loose multi stranded very fine wire so that it can allow the coil to move easily up and down your magnet flexing a million times without fatigue cracking that would disrupt current flow.

BTW the voice coil is firmly attached to paper cone and when you think about it, a speaker is small linear motor.

Click the pic to see the entire image..

if there are two voice coil around the magnet then it effects or not?

Referring to to the above single voice coil above it is a cut away.

The multiple voice coils probably think the design engineers see some sort of advantage in doing that way.

what do you mean by voice call? i've used a big magnet with hole inside it and wrap a coil around it almost 20 times is it true or i've to change it?

Study the pictures of voice coils and how they slides up / down.

sir i've make a speaker through cofee cup and used a big magnet with a hole inside it and wrap a coil around magnet about 20 times then attached the ends of this coil to magnet but it doesn't work? where is am i going wrong?

Thats not exactly how speakers work.Assuming I understand what you have done. A picture or two would help.

Normally a loud speaker will have a magnet - generally cylindrical, with a coil of fine wire wrapped round the magnet - loose so it can move up and down.

Applying your audio to this coil will cause it to move.

To make the sound loud the coil is connected to a paper or plastic cone to spread the sound.

Have you done something like this picture?

yes of course you tell me please that a magnet with a hole inside it work or not..............

It depends on how you have used it. But it depends on how you use it and how the magnet is magnetized.

The illustration below might work.

Didn't add picture

Under the words "

Didn't add picture"

seperate question ask it again as a seperate question

I've a charging light containing 15 LEDS but its battery is dead now i want to repair it by replacing another battery but when i replace it with another battery the LED donot glow up to their full capacity how can i glow it up fully?

how can i improve it?sir i've make a speaker through cofee cup and used a big magnet with a hole inside it and wrap a coil around magnet about 20 times then attached the ends of this coil to magnet but it doesn't work? where is am i going wrong?

The coil isn't supposed to be attached to the magnet, Check this video, It should explain what you need