Sounder: A sounder is an electrical device that produces sound. It is commonly used in alarm systems, as well as in other applications. Sounders typically consists of an electromechanical transducer, such as a bell, buzzer, or piezo element, driven by a signal from an electronic circuit. The sounder may also contain an amplifier that increases the volume of the sound.
Buzzer: A buzzer is an electronic device that produces an audible sound, usually in the form of a buzzing or beeping noise. It is commonly used in warning systems, alarms, and other applications. Buzzers typically consist of an electromechanical transducer, such as a piezo element, driven by a signal from an electronic circuit.
Microphone: A microphone is an acoustic-electric transducer that converts sound into an electrical signal. It is commonly used in recording and sound reinforcement applications, as well as in telephone systems. Microphones typically consist of a diaphragm, which vibrates when sound waves hit it, and a transducer, which converts the vibrations into an electrical signal.