Thanks @MarkT. It turns out that I had not check the datasheet of my passive buzzer; it has a 30V input. I have therefore ordered the following SMD Diaphram External Piezo Buzzer Transucer (https://docs-apac.rs-online.com/webdocs/14f7/0900766b814f7168.pdf). Resonant Impedance is 500 ohms with 20nF capatictance. How do I need to use a resistor for this?