[sdiy] Hand-matching capacitors for filter stages

[Harry Bissell]

Yes, the difference is in the dielectric. Polystyrene needs to be thicker,
forcing the plates apart and the capacitance down, so you need more area.

Polystyrene also has a lousy soldering temperature range, use is only 85C.
Polypropolene is MUCH better temperature-wise

H^) harry


----- Original Message -----
From: cheater cheater <cheater00 at gmail.com>
To: Tom Wiltshire <tom at electricdruid.net>
Cc: synth diy <synth-diy at dropmix.xs4all.nl>
Sent: Tue, 9 Feb 2010 10:31:58 -0500 (EST)
Subject: Re: [sdiy] Hand-matching capacitors for filter stages

> One of my motivations is actually that 5% polypropylene
> caps are available in convenient 0.2" pitch boxes, whereas the 1%
> polystyrenes are mostly available in a board-hogging almost-20mm axial lead
> format.

Maybe there's a reason for that?

D.

On Tue, Feb 9, 2010 at 16:27, Tom Wiltshire <tom at electricdruid.net> wrote:
>
> On 9 Feb 2010, at 15:14, cheater cheater wrote:
>
>> Tom,
>> good question regarding the tolerance vs material. I'll be thrilled to
>> find out what is going on there.
>>
>>
>> Regarding hand matching capacitors: Is your time worth the price
>> difference?
>
> No, probably not. One of my motivations is actually that 5% polypropylene
> caps are available in convenient 0.2" pitch boxes, whereas the 1%
> polystyrenes are mostly available in a board-hogging almost-20mm axial lead
> format. It might cost me some time, but it'd save me money *and* PCB space.
>
> T.
>
>
>
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-- 
Harry Bissell & Nora Abdullah 4eva