If you just want to amplify tones generated by the Arduino, try the attached schematic. It will deliver about 0.3W into 8 ohms. If you need more volume than that provides and you want to run the amplifier from 5V, then I suggest this chip http://www.ti.com/lit/ds/symlink/lm4871.pdf of someting similar.[EDIT: corrected transistor types]
It's simple because it only has to amplify square waves of a fixed amplitude
I use LM386N8's...
2SK1058 is one type power MOSFET suitable for audio power amplifier, and it has very high Ron (~15 Ohms).
I studied some electronics YEARS ago so I can get a feel for some of his design but I can't see what is gained by dropping half the power across a 40W resistor.
that and the cost of a 40 watt resistor could feed your family dinner
Please enter a valid email to subscribe
We need to confirm your email address.
To complete the subscription, please click the link in the
email we just sent you.
Thank you for subscribing!
via Egeo 16