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Ceramic VS Film

Started by skypn, July 09, 2020, 12:52:32 PM

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skypn

Many schematics show non-polarized caps, but do not tell which kind to use. Consider this Schematic;



Which of the non-polarized caps are which? What is the criteria for the selection?
TIA
Knowledge for Knowledge's Sake

EBK

#1
Generally, choose film caps whenever possible (doesn't matter a whole lot what type of film, as long as it fits your board).  For pF range caps, ceramic are more typical.  If you choose ceramic caps with a NP0 or C0G dielectric, the value will be more stable.

Audio is considered a "general purpose" application for caps, so there are tons of different ones that will work just fine.
"There is a pestilence upon this land. Nothing is sacred. Even those who arrange and design shrubberies are under considerable economic stress in this period in history." --Roger the Shrubber

skypn

Knowledge for Knowledge's Sake

benny_profane

For the pF range, I usually use MLCC instead disk ceramic caps. That's mostly because I have the mouser product codes in a spreadsheet, but others may be able to chime in about the attributes of each (i.e., microphonic behavior, stability, etc.). In either case, the NP0/C0G dielectric indicated by EBK is the way to go.

Aentons

#4
Here is a good visual chart that shows the range of values that each type is generally available in. It's like the other guys said, use film where you can. If film is not available for a certain value, use ceramic for lower values, and electrolytic for higher values. Sometimes there are certain use cases where it's better to use one type over the other, but that's the general rule of thumb. Also, I have heard that tantalum is a conflict material so don't use those if you can help it.

Oh, and there are also mica caps available for smaller values in the pF range which can be used in place of ceramics sometimes but are slightly more expensive.