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Can I build a simple 50mV to 150mV ac amplifier?

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Addez

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Hi!
I'm experimenting with ac radiosignals.
So I made a program in java capable of reading the microphone (and headphone) input.
I can use a mic and when I talk I can see my wave move in the screen.
I can measure that both the mic and the antenna on my rc-controller have ac current in them.

Problem is, the ac current coming out of the rc-controller is 50mV and the rc from the mic is 150mV roughly measured with an orsilloscope.


Now could I easily convert that 50mV to 150mV using a 9V battery?
If not, any suggestion on how to continue?
 

FvM

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The soundcard microphone input has sufficient sensitivity to process 50 mV as well. So you won't need an amplifier.

I'm surprized to hear about AC current of 50 mV...
 

Addez

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That is weard because when I output sound to an antenna, I simply connected the red wire in my TRS plug to the antenna. And I can measure the ac at the top of the antenna.
Now connecting the redwire in a TRS plug to the antenna of my rc controller does not give any sound at all.
Tho Im not looking for the sound (as its above hearing (27MHz)) Im looking to get the input so that I can read it using a program and calculate input data..

Maybe what Im looking for is no amplifier but instead something to reduce the frequency by like 1000 times?
 

potdarsagar

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Bro its difficult to amplify such small voltage.and 10mv is voltage, don't Call it as current.current is measured in amp.Bro just an guidance , we Can amplify currents using amplifier using transistors, BUT amplifying such small voltage is very difficult.if i get Any solution will post here.
 

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The sound input can only process input signals with a frequency below 20 kHz. No chance for the RF signal of a RC transmitter. If you know the involved modulation, you can possibly make a simple receiver. If it's AM, a signal diode would be sufficient.
 

Addez

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I was thinking sending and reciving information using pulses of amplitudechanges, not sure if that is what AM was but that is the type of signals that the rc car would respond to.

Anyhow I would need to a frequency changer..
Is it easy or way hard to make a chip that changes the incoming ac to maybe 1/10^5th?
Couldn't that be done using the right type of capasitator? Or would that turn the ac to dc?
 

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