Hi guys, Thank you very much for trying to help me. The PWM frequency is about 150kHz, my sound is sampled at 22050Hz using 8 bits. I tried using a low pass RC filter but then the sound level is even lower. I read somewhere on the web that if i feed the pwm signal directly to the speaker it would be ok since the speaker cannot react at 156kHz anyway. It works, i can say i don't have any noise except the one generated by the fact i am using 8 bits per sample. I thought about limiting the current from the base with R1. The impedance of my speaker is 8 ohms, max. power is 0.8W. I can take a few pictures with my circuit if they might help. My power source is a bench source delivering 5V / 1.5A, i am not using any LM7805 or other regulator. Both the PIC18F and LM386 are powered from 5V. On Thu, Nov 5, 2009 at 6:28 PM, Herbert Graf wrote: > On Thu, 2009-11-05 at 00:59 +0200, Dumitru Stama 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. > > What is the impedance of your speaker? What's the frequency of your PWM? > What's the purpose of R1? > > TTYL > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist