From: firstname.lastname@example.org (N. Thornton)
Subject: Re: Wrestlemania Royale: Tantalum vs. Electrolytic Vs. Polys, etc.
Date: 25 Oct 2002 05:20:48 -0700
NNTP-Posting-Date: 25 Oct 2002 12:20:48 GMT
Dan Charette wrote in message news:...
> Hey Folks!
> On the subject of capacitors in a nutshell, what are the main
> selection points why one would choose say an electrolytic over a
> tantalum? i.e. Aside from ESR criteria, in say a decoupling situation
> on the power supply pins of an op-amp, what would be the couple of
> reasons why one would choose electrolytic over tantalum or vice versa?
> And on that same note, say the same op-amp used in a simple amplifier
> scheme with a HF rejection cap across the feedback path, what would
> you choose there, polypropylene, polyester, ceramic, foil, etc. and
> why? And say in a digital scheme on the decoupling caps, what
> there... ceramic...metalized polyester film... etc.?
Dont forget glass, mica, silver mica, oil, paper, electrolytics, wet
electrolytics, tantalums, and several types of plastic films and
ceramics. And I suppose one should mention pith balls too :) And
perhaps PCB stray capacitance, and air and plastic spaced variable
caps and trimmers... The choice is mind boggling if you dont know
where to start.
> While on the subject of caps, why not discuss resistors too. Metal
> oxide film, carbon film or carbon composition?
Or wirewound, carbon pile, and a goodly list of non linear resistors
too. And conductive plastic resistors, thick film, thin film, and the
once popular pencil track, much used in the war to patch up bad pots.
Carbon composition arent much used these days, carbon film behave much
> Given an unlimited budget on a circuit design, what are the high
> performance materials in the way of capacitors and resistors that one
> would use in say an audio amplifier circuit or a high speed digital
Metal film resistors are good and distortion free.
Most plastic film caps are good for audio too, the ones to be
suspicious of when used in the signal path are ceramics and
electrolytics, which aren't distortion free at all.
> I say the most colorful components are the ones that are the most
> worthy of selection.
Sometimes thats true, though mostly it doesnt matter a bit.