alarm clock
US /əˈlɑːrm klɑːk/
UK /əˈlɑːrm klɑːk/

1.
despertador
a clock that can be set to wake a person at a particular time by sounding a buzzer or bell
:
•
I set my alarm clock for 6 AM.
Eu ajustei meu despertador para as 6 da manhã.
•
The loud ringing of the alarm clock startled me awake.
O toque alto do despertador me assustou e me acordou.