[sdiy] Capacitor types - which when?

[Metrophage]

--- Julian <julian at 22host24.com> wrote:
> Im in the process of working on some EFM boards.  In most cases the
> type of
> capacitor is not specified.

Feel free to post which modules and caps you are wondering about! I
have many EFM boards on the bench, quite a few of them done. Also I've
got documentation for nearly every project Tom has posted for the past
six years. Just about every instance of unlabeled capacitors I can
recall was a .1 or .01 ceramic, though I am not completely certain.
With EFM modules the schematic diagram is your most reliable "parts
list".

> Im just wondering as to the pros and cons or various types.  Ceramics
> vs poly layer vs poly film etc.etc.

Ceramics are typically used for bypass caps to reduce noise from the
supply leads, or where accuracy is not very crucial. Mica and Mylar are
general purpose caps which are usually rated about 5% tolerance- more
versatile than ceramic but not as cheep. Polystyrene caps are probably
the most stable that you can find, typically made in small values.
Polyester are nearly as tight as styrene, and made in more of a variety
of values. Polycarbonate exhibit the least leakage, though appear to be
seldom produced.

> Can someone give me a brief outline of whats what, or point me to
> some good
> text to read on the subject (preferable with relation to synth work)?

My fave reads about such stuff are "Electronotes" newsletter, Barry
Klein's "Electronic Music Circuits" book, and Hal Chamberlin's "Musical
Applications of Microprocessors". Also, reading service manuals to
audio equipment can on occaision be elucidating. The searchable archive
to this list is great!
< http://www.buchi.de/sdiy/ >

Enjoy!
CJ


	
		
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