Yes, I worried about that, and black plastics foam material MAY be a
problem, but in my experience, the conductivity is designed only to
dissipate static. At low voltage/impedances, its conductivity is pretty
negligible. In fact, achieving respectable conductivity in a
soft rubbery plastics foam sheet is quite a trick.
Examples of this are the semi-rigid foam pads used to hold IC's.
Normally its necessary to stuff the foam so full of conducting fillers
that it becomes rather stiff and non-resilient. Thats not what I had in
mind.
I used some soft pink stuff, rather like thick blotting paper, and I
hacked it to avoid bridging terminals at opposite ends of that PC board
holding the relay. So far no smoke, but I agree that a little care is
appropriate. I wish the original TT foam pad was available; it would be
interesting to stick an ohm meter across it and across a piece of the
stuff I used.
John
On 29-Sep-99 Steve Ellington wrote:
>
> Watch out for some of that circuit board foam. IT's made to conduct
> and
> prevent static buildup. Not too good for RF insulation.
>> --
>
> Steve Ellington N4LQ
> N4LQ@IGLOU.COM
>
>
> --
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----------------------------------
E-Mail: John - G3JAG <patents@dx0man.prestel.co.uk>
To: <tentec@contesting.com>
Date: 29-Sep-99
Time: 23:55:17
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