Hi,i'm implementing a shadow alarm,and i use a buzzer as an indicator.we i branch it to 5V it produces too much sound but when introduced to the circuit it is barely making some sounds.
i think because its output is from an IC so there is some problem of impedance matching.
thanks for anserwing.

 

Based on no information about which IC, which buzzer, or how much current, I'd say you aren't getting enough current to the buzzer.