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Dead accurate 1Hz clock signal???


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The most accurate way to do this is to use a crystal oscillator and a divider circuit. It can also be done accurately with a micro, since you program the timing. This is basically the same as a programmable divider since all functions in the micro are based off the clock cycles of the micro.

MP

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Hi,

Lovely TOPIC. there are time signals broadcast  terestrially. like 10MHz, 15MHZ and many other. they provide time ticks at 1sce-- these are controlled by atomic clock .

second , you should have DCXO- which provides a good standard clock and derive 1sec from this clock-- appears foolish is it not-- but when you used dead perfect 1sec pulse-- you may appreciate perhaps

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The most accurate way to do this is to use a crystal oscillator and a divider circuit. It can also be done accurately with a micro, since you program the timing. This is basically the same as a programmable divider since all functions in the micro are based off the clock cycles of the micro.

MP



http://www.electronics-lab.com/projects/oscillators_timers/015/index.html

I built a clock with 555 timer and dual decade counters......But it wasn't accurate obviously because of 555....As MP said crystal oscillator will be better.....the above project can be extended to make hrs/min/sec clock.....u will have to use gates to reset the hours section when it strikes 24.......
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If you're powering your device from the mains, another option is to divide down your 50/60Hz signal to get 1Hz.

Not particularly accurate, as the mains frequency wavers quite a lot. If you assume a +/- 1Hz deviation, that could be 30 minutes off in a day!

Of course, most of the time the deviation is a lot less than that. It's quite interesting to see what happens the the frequency based on demand:
http://www.dynamicdemand.co.uk/grid.htm

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Ok, crystal oscillators it is! Does any one know where I can look at some? Does anyone have any suggestions for what I should look at?


u need a crystal of some frequency,then divide that frequency to suit your need......didn't u look at the project of the electronics-lab project section? .......
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The simple most circuit for this would be to take the circuit chip out of a dead watch or a table clock. They use a crystal oscillator and dividing technique. You need to cut off the coil winding and add two diodes (IN4148) on both the outputs (P side of it) and join the N-side to get study 1-Hz clock.

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The simple most circuit for this would be to take the circuit chip out of a dead watch or a table clock. They use a crystal oscillator and dividing technique. You need to cut off the coil winding and add two diodes (IN4148) on both the outputs (P side of it) and join the N-side to get study 1-Hz clock.


Hi
it is working with a single cell-- you need to level shift to TTL or CMOS in order that it is useful


sarma

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