thank you so much! I was giving up on my tiny speaker which was soooo quiet. And now it is LOUD. I did use a 2N2222A .. not sure what the A means but it works great

how about bc548 transistor? how much loudness will i get using the bc547?

thanks for posting it was i m looking for few days

So I have the adafruit hooked to a 50w amp. How do I turn the boards volume up. Just volume+ and ground? How will I know when it's up all the way?

I’ve seen a version of this with a capacitor and resistor added to the circuit. Are these necessary?

HMMM cant seem to get this to work using a BC547B. Trying to boos the sound from a piezo buzzer a little bit for an Arduino EMF detector I made but with the BC547B in line as i this video no mater what way it goes in the buzzer is canstantly sounding

Thank you so much

How can do siren sound

connected to piezo speaker, sound output more quiter....any suggestion, please help? ^_^

cool stuff big guy

Would this work on a piezo disc ?