I have an Arduino Pro Mini 3.3v and the voltage is too small for my buzzer to ring loudly. I want to add a 9v battery to power the buzzer.
This is my current circuit:
Arduino (pin 9) => Buzzer +ve
Arduino Gnd => Buzzer -ve
I want to power the buzzer using an external 9v battery but I have no idea how to implement it in the circuit. All I know is that the ground should be common.