Hi, I have enough voltage in my PWM signal (~4.5V) but not enough current to drive that small speaker. I can hear the sound but is weak. I will try with that push-pull suggested in the previous posts to see if the results are better. Thank you for your reply Dumitru On Sun, Nov 8, 2009 at 7:28 PM, Vasile Surducan wrote: > 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 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 >> >> -- >> 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 > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist