LED with MP3 player transistor to bright up light.

Hi all, i m trying to build a circuit to light up LED with an MP3 player. I mean LED will blink or light with sound signals. It goes fine. But LED is not so bright. I. Think i need to amplify the current using a transistor. But i dont know much about them. So plz guide me what transistor or some thing other should i use. I want it to be easy and simple.

How you conect existing led ?

A single transistor will be sufficient to drive an led. (See schematic below.)

LED brightness will be according to sound volume.

Be careful not to admit too much bias current.

thanx dear. but i am a newbie to electronics, and don't know much about those components. i want extremely simple example. i did get the idea what you suggested. but i want it to be more simple. for example removing sensitivity adjust some resistor

Yes, the simpler the better.

The resistor inline with the led can be 47 ohms if your supply is 2.5V (example, two rechargeables).
Or 68 ohms if supply is 3V (example, two new alkalines).
This resistor is needed so you don't burn up the led.
If your supply is higher than 3V then you must use greater resistance.

The input resistor should be somewhere between 2.2k and 10k, depending on the volume coming from your player.
If this resistance is too low then it can cause distortion in your audio.
If too great then your led will not get bright enough even when audio volume is high.

You understand it is only possible for us to give ballpark figures, since we cannot know the operating parameters of your equipment.

It will be up to you to experiment with a range of values, to obtain the performance you want.