A premium digital clock radio with digital tuning.
An alarm clock is a clock that is designed to make an alarm sound at a specific time. The primary use of these clocks are to awaken people from their sleep in order to start their days in the mornings, but they can also be used for other reminders, such as when timing when cooking. To stop the sound, a button or handle on the clock needs to be pressed, or it stops by itself after a few minutes. A classical analog alarm clock has an extra "hand" that is used to specify the time at which to activate the alarm.
Basic digital alarm clock without a radio.
Traditional mechanical alarm clocks have a bell on top and which rings, but digital alarm clocks can make other noises. Simple battery-powered alarm clocks make a beeping sound whereas novelty alarm clocks can speak, laugh, or sing. Some alarm clocks have radios that start playing at a specified times, and are known as clock radios.
A wind-up, spring-driven alarm clock.
In a mechanical bell-style alarm clock, a spring drives a gear that propels a clacker back and forth between two bells or between the sides inside a single bell. In an electric bell-style alarm clock, the bell rings with an electromagnetic circuit and armature swinging back and forth turning the circuit on and off again repeatedly.
Clock radios
Modern digital alarm clocks typically feature a radio alarm function as well as a beeping or buzzing alarm, allowing a sleeper to awaken to music or news radio rather than harsh noise. Most also offer a "snooze button", a large button on the top that stops the alarm and sets it to ring again at a short time later, typically 10 minutes. This feature is used to gain additional rest.
Newer digital clock radios often use a battery backup to maintain the time in the event of a power outage. Without this feature, digital clocks will reset themselves incorrectly when power is restored, causing them to fail to trigger the alarm.
A basic digital clock radio with analog tuning.
Computer alarms
Alarm clock software programs have been developed for personal computers. A PC acting as an alarm clock may allow an unlimited number of alarm times, personalized tones, online features (such as news and weather reports), and even features for insomniacs. While PCs allow features and flexibility ideal for office reminders, most people still prefer the simplicity and beside convenience that an ordinary alarm clock offers for morning waking.
See Also
- Timer
- Digital clockde:Wecker
es:Despertador
nl:Wekker
pl:Budzik
sv:Väckarklocka