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Electronics => Beginners => Topic started by: JoeN on August 17, 2016, 12:42:57 am

Title: Help me decide/decypher capacitor types for this schematic
Post by: JoeN on August 17, 2016, 12:42:57 am

This is a circuit I would like to try to build.  I have one problem with this thing, I can't tell what capacitor types Jim wants me to use based on his instructions.  He says:  1) Do not use ceramic capacitors anywhere.  2)  Use Mylar or Silver Mica.  3)  0.01uF=Polystyrene Preferred.  These instructions just don't make sense to me because a bunch of the values are way too big for Mylar/Silver Mica and a bunch of the capacitors on the schematic are polarized, this seems to me he is indicating electrolytic, right after saying not to use them.   I guess you have to.  Here are the capacitors on the schematic, what kind do you think they should be?

10000pF - Use polystyrene like Jim said?  Are there more modern choices that would work?  Could polypropylene be used instead?  How about mica?
5pF - mica?
6800pF - mica?
.1uF - since ceramic is out, I guess we must use aluminum electrolytic?
.47uF - since ceramic is out, I guess we must use aluminum electrolytic?
1uF - since ceramic is out, I guess we must use aluminum electrolytic?
15uF - Aluminum electrolytic?
10uF - Aluminum electrolytic?
47uF - Aluminum electrolytic?
100uF - Aluminum electrolytic?

Schematic:

(https://www.eevblog.com/forum/beginners/help-me-decidedecypher-capacitor-types-for-this-schematic/?action=dlattach;attach=248449;image)

http://cds.linear.com/docs/en/article/ubm_edn_20110811%2018Bit%20ADCs%20Ad%20Free.pdf (http://cds.linear.com/docs/en/article/ubm_edn_20110811%2018Bit%20ADCs%20Ad%20Free.pdf)

Title: Re: Help me decide/decypher capacitor types for this schematic
Post by: Len on August 17, 2016, 06:56:39 pm

It doesn't specifically say not to use electrolytics, only ceramics are completely banned. I think it's obvious that the polarized caps (all fairly large values) are meant to be electrolytic.

Mylar (PET) capacitors are easily available in the microfarad range, I don't see a problem with using those for the 0.1, 0.47, 1 uF values.

Title: Re: Help me decide/decypher capacitor types for this schematic
Post by: SeanB on August 17, 2016, 07:31:56 pm

5pF can definitely be a NPO ceramic, and for the 6n8, 10n, 100n, 470n and 1uF use either polyester or polypropylene, which will work here.

Title: Re: Help me decide/decypher capacitor types for this schematic
Post by: JoeN on August 17, 2016, 10:54:02 pm

Thanks for both replies!