[sdiy] Mystery Caps

[harrybissell]

The zero-ohm resistor has another advantage... It can be used on a double
sided (pre PTH) board to allow traces to run under it without fear of short
circuits...

This was in the days before plated through holes, and soldermask was very
uncommon as well.

Its true the major reason was pick and place... but at that time machines were
available
to insert 22ga wire jumpers (also supplied on tale and reel)

H^) harry

Wayne Dubois wrote:

> We used to see these used alot as the usual bypass cap (.1uf, marked '104').
> Our guess was that the form-factor made it easier on the pick and place
> mechanisms for auto-insertion.
>
> I still get a giggle when I see a 'zero ohm resistor' which, I presume, is
> used for exactly the same reason.  (These will have the same axial pkg as a
> standard %5 resistor, but with a single black band in the middle.)
>
>  - w
> ----- Original Message -----
> From: "Neil Johnson" <nej22 at hermes.cam.ac.uk>
> To: "Michael Ruberto" <frankentron at hotmail.com>
> Cc: <synth-diy at dropmix.xs4all.nl>
> Sent: Sunday, March 16, 2003 10:16 AM
> Subject: Re: [sdiy] Mystery Caps
>
> >
> > > not with a value .47uf.
> >
> > Ah, right :-)
> >
> > > >But my guess is that they could be glass-encapsulted multi-layer
> ceramic
> > > >capacitors.  The "50V"  rating sounds like they might be these.
> > >
> > > hmmm ceramic, so I guess I can assume at least 10% tolerance? is there
> any
> > > benefit to glass encapsulation? good humidity resistance?
> >
> > They look nice?  Seriously though, certainly quite resistant to moisture,
> > as long as the glass-metal seals are good.
> >
> > Neil
> >
> > --
> > Neil Johnson :: Computer Laboratory :: University of Cambridge ::
> > http://www.njohnson.co.uk          http://www.cl.cam.ac.uk/~nej22
> > ----  IEE Cambridge Branch: http://www.iee-cambridge.org.uk  ----
> >
> >