My BE project is sound charger.Can i use a transformer to amplify signal from microphone from 3mV to 3Volts.?

I want to charge cellphone with the power of sound for which we are using a microphone.The output of the microphone is in millivolts.I would like to know if I can amplify my signal with a transformer because I cannot use any external power supply.Also we are thinking to store this amplified signal in an inductor.Is this the right way to go?If yes also suggest the transformer design for the same.

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Use a big speaker. a microphone doesn't provide a good power source.

Kiteman3 years ago

Sound is a very poor source of energy to transform into useful electricity, as the output of your microphone shows - decades of research and development into the technology, and it only produces a millivolt signal.

Pick a different resource to harvest, you'll have a lot more success:


iceng Kiteman3 years ago

Another very good link from a favorite fellow that I follow ;)

Kiteman iceng3 years ago


Volts up amps down.

So sure if the output of the mike is 3 mv 100 amps.

Can you suggest any simple alternative of charging the cellphone with sound energy.?

rickharris3 years ago

Not really - and by the sounds of it you may want to rethink your project as your electrical knowledge is very weak.

You may want to investigate getting energy form a more physical source - eg the passing of feet, cars, wind solar.

A car driving over a pheumatic tube which is connected to a turbine will generate quite a lot of energy. But then again the car is very heavy.

PS this isn't free energy.

abhishekardile (author)  rickharris3 years ago
Then what can be an alternative for a microphone keeping the principle of the project same of charging the mobile with sound?Would you suggest me any such alternatives of charging cellphone with any form of sound energy?
iceng3 years ago

Any mike only generates less energy then a fly,

Other wise you could cause bridges to fall by yelling too loud.

You can bring down a bridge with your voice.

5. 4. 3. 2. 1, Fire in the hole, Fire in the hole, Fire in the hole.

verence iceng3 years ago


There's just not enough energy in sound waves.

iceng iceng3 years ago

BTW a transformer only exchanges voltage for current.

So if you want to multiply 3mv to 3Volts a gain of 1000X the input current must be a thousand times greater then the output !