Boosting the signal output from a MP3 player

Thread Starter

Otaku

Joined Nov 19, 2008
128
Hi all,
I'm trying to find a simple transistor amplifier circuit that can boost the signal from a MP3 player from the typical 0.5 - 1.0mV range up to a value that can drive a transistor switch (~1V). For simplicity's sake, I'd like to avoid using op-amp IC's, if possible. The very low voltage from the player can't pull up the base on the 2N2222 that I'm using for the switch. All advice is appreciated!

Gary
 

bountyhunter

Joined Sep 7, 2009
2,512
I don't know where you got the spec of 1 mV for an MP3 player output? The ones I have that drive headphones put out way more than that, probably more like 500mV signal at 0 dB.

And what are you expecting the amplifier stage to drive?

What signal level do you need it to put out?
 

Thread Starter

Otaku

Joined Nov 19, 2008
128
Thanks for the reply, bountyhunter. I re-checked the mV values for my player and get 10-12mV DC, and ~250mV AC when it's playing a sound file (had the wrong scale set on the DMM). What I need to do is boost this voltage high enough to turn on a 2N2222 transistor, I'm assuming >/= 0.7VDC. I want to use the 2N2222 to switch 5VDC to a small DC motor.
 
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