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Connecting Crystal Osscilators?

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grrr_arrghh

New Member
Hi

i am trying to make an accurate clock, using a crystal and some cascaded 4017 or 4026 ICs

I can use 10, 16 or 18.432 MHz crystals. The diagram below shows how someone suggested I use the crystal. Could connect the bit marked output on the diagram straight to the input of the 4017/4026?

As my clock needs only to count up in 1/100s of a second, how would i divide/multiply the output of the crystal to get 100Hz?

All help greatly appreciated

Tim
 

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Styx

Active Member
off the top of my head the easiest way to divide a clock is via using cascaded T-type's (toggle D-type registers) You can make a toggle from J-K flip-flop.

By using the output of yr clock as the toggle input to the first T-type. Use the 1st T-type output to be the 2nd T-types input. 2nd T-type output to third T-types input.

Keep this up. Each output will be a factor of 2 in frequency down from the previous output.


However you say you have a MHz range crystal.It will take alot of D-type to sub-divide. Why can't you use a 32kHz crystal. That is the standard value for timing?
 

grrr_arrghh

New Member
oh, ok

thanks - the reason for the values was that they were just what i had to hand, but i can get a 32K if thats what u recomend.

what ICs have JK flip-flops in them? Also, any chance someone could draw me a quick diagram of how to connect them up? (i am in new teritory as far as electronics are conncerned)

How would i divide a 32K to get 100Hz (if divided by a factor of 2, closest I can get is 125Hz, or do I divide to 1000Hz, then divide by 10?)

Last question: if I used te diagrams above, and chose a 10M resistor that was spot on 10M, would the accuracy of the clock be limited to the accuracy of the crystal?

Thank you VERY much

Tim
 

panic mode

Well-Known Member
Did you think of using CD4060 chip and 16.384MHz, 8.192MHz or 4.096MHZ crystals?
 
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