Hi Dumitru,
The schematic posted is an emiter repeater. It does not amplify the
voltage, only the current flow through your low impedance speaker. If
the PWM is properly filtered, you have the chance of hearing almost
nothing, but this is logic.

Vasile

On 11/4/09, Dumitru Stama <spanac@gmail.com> wrote:
> Hi guys,
> i have a question. My PIC18F2520 is set up to output a PWM signal. I
> want to amplify the signal's current and feed it into a speaker.
> Right now using only a single PN2222A i can hear the sound but the
> volume is quite low.
> I tried a LM386 and the output is what i really want but only if i
> select the 200x gain schematics.
> I don't know what should i try now, i really want to use only simple
> components and not a dedicated amplifyer like LM386.
>
> Thank you very much in advance
> Dumitru Stama
>
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