Jump to content
Electronics-Lab.com Community

Dead accurate 1Hz clock signal???


Recommended Posts


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

Link to comment
Share on other sites

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

Link to comment
Share on other sites


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.......
Link to comment
Share on other sites

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

Link to comment
Share on other sites


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? .......
Link to comment
Share on other sites

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.

Link to comment
Share on other sites


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

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
  • Create New...