capacitor value? - Printable Version

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RE: capacitor value? - hornychz - 20-03-2019

(20-03-2019, 18:17)WetCoast Wrote:  my readings. It's kind of hard to read the numbers on the capacitor but it says 104 and the meter reads 43.0 nF
Do you think this is a problem? or will I be OK using these capacitors for the TX board C1, C2, ETC?

Hi again,

Although I am not the author of the involvement, I am convinced that it is without problems. Even if the capacity of the capacitors
was really half, nothing would change the function. Capacitors are probably only used to conduct potential RF oscillations to the ground.

Good luck! 

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RE: capacitor value? - WetCoast - 21-03-2019

Thanks again.
I was hoping the value for these capacitors was not too critical. I'm not clear as to how the values are calculated, is there some sort of formula or ??

Cheers!

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RE: capacitor value? - TassyJim - 21-03-2019

(21-03-2019, 02:53)WetCoast Wrote:  Thanks again.
I was hoping the value for these capacitors was not too critical. I'm not clear as to how the values are calculated, is there some sort of formula or ??

Cheers!

The capacitors across the rain and wind inputs help eliminate contact bounce.
These capacitors also help reduce RF interference, especially from the long leads going to the sensors.
Other capacitor are across the power supply rails to reduce any noise caused by the high frequency switching, something that all processors do.

While you can calculate ideal values for some situations, the usual practice is to add 0.1uF capacitors in all likely places. If very high frequencies are involved, 0.01uF capacitors are often used.
If your capacitors are 0.047uF as your meter suggests, they are perfectly OK to use and will be just as effective as a 0.1uF
I can't see anywhere in the circuit whey capacitors are used for timing (when the value would be significant)

Jim

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RE: capacitor value? - WetCoast - 22-03-2019

Thank you very much.
This is all a learning experience for me.

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RE: capacitor value? - werk_ag - 22-03-2019

(22-03-2019, 00:29)WetCoast Wrote:  ...
This is all a learning experience for me.

Exactly the same for me.
Since I started this project some years ago, it always was (and still is) a learning process. Watch out, the Weatherduino can be addictive.

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