Amplify Pizzo Buzzer
Part 1:

There a couple types of sound-making elements out there. The first is piezo elements. They move when voltage is applied to them. If you have a piezo then I suspect the click you hear is the rising/falling edge of the DC voltage you are applying. To fix this, you will need to apply an AC signal at the frequency you wish to produce. This should be achieved with a PWM signal producing a square wave.

The second is an integrated buzzer. This device will simply make noise when adequate power is supplied. Perhaps your simplest solution is to move to one of these.

Part 2:

In either case above, you may need more current than the Arduino can produce directly. To achieve this you can use the following simple circuit:







simulate this circuit &ndash; Schematic created using CircuitLab