Date:         Thu, 17 Aug 2000 14:41:17 -0400
Reply-To:     David Beierl <dbeierl@attglobal.net>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Beierl <dbeierl@attglobal.net>
Subject:      Re: Capacitor fix questions
Comments: To: Brian Cirulnick <techrat@vm.com>
In-Reply-To:  <450BF163A931D4119C2B00D0B774183DE83D@exchange.vm.com>
Content-Type: text/plain; charset="us-ascii"; format=flowed

At 13:02 8/17/2000, Brian Cirulnick wrote:
>Here are the available choices:
>10 microfarad 16WVDC Tantalum Capacitor
>22 microfarad 35WVDC Electrolytic Capacitor
>
>Can I substitute the Electolytic for the Tantalum?

Ye-e-e-e-e-essss -- but bad idea.

>Or is 10microfarads okay instead of 22?

That was tried, not big enough.  Also the 16WV is probably enough, but 25
gives better margin.

Radio Shack has it as an RSU (special order) item, have them look it up in
their RSU book.  Where I live they get special orders in 2-3 days.


>I know that the Electrolytic has completely different properties than, say,
>Ceramic caps, but I don't know the differences between Elec and Tant - I'm
>just not enough of an EE to know this stuff - and it wasn't covered in Art
>School...


Capacitors achieve capacity by the inverse product of plate area and plate
separation.  An electrolytic cap achieves enormous plate area and miniscule
separation by chemically etching a foil and then causing an oxide film to
form on it.  The "ordinary" ones use aluminum foil.  Tantalum caps use
tantalum foil instead, and better packaging.  They have less leakage,
better stability, longer life, blah blah blah.

david
David Beierl - Providence, RI
  http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage"
'85 GL "Poor Relation"