# How does an alarm digital clock work?

Ramned
Science 14 Mar '08 21:08
1. Ramned
The Rams
14 Mar '08 21:08
A) How does the digital clock work in terms of electrics?
B) How does the actual alarm work? In terms of electricity?

(I am pretty clueless.)
2. sonhouse
Fast and Curious
14 Mar '08 22:54
Originally posted by Ramned
A) How does the digital clock work in terms of electrics?
B) How does the actual alarm work? In terms of electricity?

(I am pretty clueless.)
There is an oscillator inside, usually 32400 hertz (cycles per second) something like that frequency anyway, a quartz crystal oscillator that keeps pretty good time. The digital part comes just from counting the number of cycles the oscillator makes and converting them to seconds, minutes, hours, days, etc. The alarm is just a count of a future tic of the quartz, so one day later, you want to alarm in exactly 24 hours, the tic is set to 32,400 times 86,400 (thats the # of seconds in one day) or 2,799,360,000 tics later, tics being each cycle of the quartz oscillator. So its basically a counting timer. Then there are the extras like chronograph functions, counting hundreths of a second and the like. One hundreth of a second would be the quartz oscillator ticking off 324 beats.
3. 15 Mar '08 14:011 edit
4. sonhouse
Fast and Curious
16 Mar '08 01:48
Originally posted by kbaumen
bad idea about what? BTW, I happened across a book at work today about piezoelectricity which is what the quartz oscillator is and found the right frequency for the watch, 32,768 Hz. I have been trying to figure out just why that number, anyone have a clue about that?
5. coquette