Alarm Clocks
An alarm clock is a mechanical or electronic devise that is designed to make an alarm sound at a predetermined time. The main use of these clocks is to awaken people from their sleep in order to start their days in the mornings, but they are sometimes used for other reminders as well.
How it works
An alarm clock is nothing but a timing device that can be set to emit some sound at a preset time. This sound can be in the form of a bell or music or any conceivable warning indicator. This alarm will continue to go off until the system is switched off by pressing a button or handle on the clock. Or the clock will continue to sound the alarm for a predetermined period of time and will go silent for a few minutes and then sound the alarm again until some one stops it
Types of Alarm Clocks
Traditional mechanical alarm clocks are constructed with a metal gong on top that rings, but digital alarm clocks can emit almost any conceivable noise. Battery-powered alarm clocks make a beeping sound whereas novelty alarm clocks can speak, laugh, or sing. Many alarm clocks have radios that start playing a specified channel at the set time; these clocks are known as alarm radios. There are even television sets that switch on at the predetermined time and play a music channel or any set channel for the time. Then there are the wind-up, spring-driven alarm clocks. In a mechanical bell-style alarm clock, a spring drives a gear that moves a leaver back and forth between two bells. There are also electric bell-style alarm clocks, the bell rings with an electromagnetic circuit and armature that turns the circuit on and off again repeatedly.
Alarm clocks have become such a common possession that everyone has an alarm today. Alarm clocks are built into wristwatches, mobile phones, portable music systems even cars and all forms of domestic appliances. And the sounds of the alarms are pleaent too. You might choose to awaken to a favorite CD, the sounds of an ocean, a soft radio, or even a gentle tone. If you are a hard sleeper requiring a loud alarm there’s a clock for you too.