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### Topic: 1hz clock (Read 13047 times)previous topic - next topic

#### baum

#30
##### May 27, 2011, 09:22 pm
But where do I get my frequency output from? I would prefer that one, though.

Thanks a lot!
baum

#### baum

#31
##### May 27, 2011, 09:39 pm
OK. and they mention a range for Rf, but for R1 they say it = XC1. What does this mean? Is it the frequency times C1 (which would be 22pf for me)? In that case R1=65,536*2.2E-11= 1.441792x10^-6?!!!!

Help!

#### baum

#32
##### May 27, 2011, 10:17 pm
I see you attached a picture of some oscillators, but these only come in frequencies higher than 1Mhz... I'll try these suggestions when the parts come.

Thanks!
baum

#### baum

#33
##### May 27, 2011, 11:02 pm
But I would need a power of 2 for it to work out. Digikey doesn't have any powers of two oscillators (2^20, 2^21, 2^22, etc.).

#### baum

#34
##### May 27, 2011, 11:21 pm
Excellent! THANK YOU SO MUCH!!!!! But I can use 4.5V (3x AA) still, right?

Also, the crystal datasheet says 12.5pF load capacitance. Should I change that, or leave it how you have it?

Thanks again!
baum

p.s. you are right about digikey, but they generally tend to be the best and easiest for finding obscure components that I can't get at sparkfun or another similar store.

#### baum

#35
##### May 27, 2011, 11:42 pm
But what about the 100pF cap?

Quote
BTW:  I found that circuit simply by Googling for: 1Hz crystal oscillator

I should be sent back to 1st grade for forgetting that. Idiot.

#### baum

#36
##### May 27, 2011, 11:48 pm
Can I just use the formulas form one of the documents CrossRoads posted?

#### baum

#37
##### May 28, 2011, 12:02 am
Quote
underestimating linear circuit design.

What do you mean?

and I will try those formulas some time...

#### baum

#38
##### May 28, 2011, 12:07 am
Are there any other easier ways of getting a 1Hz square wave with 50% duty cycle?

#### baum

#39
##### May 28, 2011, 12:22 am
You win. I'll just get the cheapest RTC they have... but I will feel a little cheated, using the sq wave of an RTC to power a clock...

Thanks for all the help, everyone. I'll try the oscillators that will oscillate some other time....

#### Showlyshah

#40
##### May 08, 2016, 11:49 pm
Just a simple idea.. But dont know if it works for you.. U can take a clock cob board from a clock or alarm.. And loop out the coil connections.. And that will give u a 1hz clock. I have used the same with peojects which needed 1hz clock.. U cant get any simpler than that.!!! Or just in 2 dollars... U cant go further cheep!

#### aarg

#41
##### May 09, 2016, 01:48 am
Just a simple idea.. But dont know if it works for you.. U can take a clock cob board from a clock or alarm.. And loop out the coil connections.. And that will give u a 1hz clock. I have used the same with peojects which needed 1hz clock.. U cant get any simpler than that.!!! Or just in 2 dollars... U cant go further cheep!
Actually, you almost can. RTC modules are down to about US\$2 with free shipping now.
... with a transistor and a large sum of money to spend ...
Please don't PM me with technical questions. Post them in the forum.

#### pwillard

#42
##### May 09, 2016, 02:15 pm
There used to be a chip for this... now its basically unobtanium.

EBAY

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