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Low speed clock
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Low speed clock

by oxim5 on Tue Aug 24, 2010 5:00 pm

Hi I am looking for a simple way to have a clock about 16 - 20 khz board real estate is limited so it must be small. also I would like to keep the component count to a minimum. I have always used ceramic oscillators. I never really designed any clocks. this clock will be used to drive some TTL chips at 5V.

Thanks for your help
oxim5
 
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Re: Low speed clock

by richms on Wed Aug 25, 2010 1:10 am

The norm for timekeeping clocks is 32768Hz, since you can divide down easily to 1 Hz. you could just divide by 2 to get the approx 16kHz that you need.

Those should be readily available with schematics etc if you have a look around.

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Re: Low speed clock

by oPossum on Wed Aug 25, 2010 2:14 am

A couple of inverting gates (inverter, NAND, NOR, XOR) can be used to make a simple oscillator.

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A Schmitt trigger gate (74HC14 or similar) only requires one inverter.

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Re: Low speed clock

by oxim5 on Wed Aug 25, 2010 9:23 am

Thanks for the tips. It was exactly what I needed!
Are those value used in the 2 gate clock just an example or will that give me 20-16 khz?
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