What is inside the electronic buzzer

I just connected my door buzzer to the Internet, by Henry

Buzzer, BreadFruit Electronics

What is the working principle of the buzzer? - Quisure

Piezo Electronic Alarm Buzzer - Alphatronic

Buzzer : Working, Types, Circuit, Advantages & Disadvantages

Buzzer Interface with Xilinx Spartan FPGA - Pantech.AI

Probots Piezo Electric Buzzer Alarm 5V 12V Continuous for Arduino

Passive Buzzer AC 12MM*8.5MM 12085 16R Resistance 3V 5V 9V 12V In Common , 5V 2 Terminals Passive Electronic Buzzer

Passive Electronic Buzzer Piezo buzzer 12085 3V 5V 9V 12V

220v Ac Cylindrical Piezoelectric Passive Discontinuity Beep Buzzer Pack of 2pcs

Electronic Spices 220v Ac Cylindrical Piezoelectric Passive Discontinuity Beep Buzzer Pack of 2pcs

What is the purpose of a buzzer in a circuit?

Piezo Electric Active Big Buzzer B27

MEETOOT Piezo Electric Tone Buzzer Alarm DC 3-24V 30x15mm High

6PCS DC 3-24V 85DB Small Enclosed Piezo Electronic Buzzer Alarm

How does a buzzer work?