> On Sep 27, 2015, at 2:03 PM, Noel Chiappa <[email protected]> wrote:
>
> Hey, everyone: those little glass capacitors (well, the casing is glass - I'm
> not sure what's inside) that one often sees used as per-chip noise/spike
> supression caps (often 0.01 uF or some such size) on 1970s/1980s vintage
> boards: are those things polarized, or can I put them in either way around?
Glass? Do you mean ceramic?
The only polarized capacitors in the sense that they suffer damage if installed
backwards are the various flavors of electrolytics.
There are a few other capacitor types that come with a recommended installation
direction; paper-insulated wound foil ones are a classic example. But that's
because the way they are constructed means that one plate ends up being the
outer layer of the assembly, which means that's the side that should be
grounded for best noise reduction in bypass applications. That's a functional
difference, not a reliability issue. Another example are the classic tubular
ceramic capacitors I remember seeing in Europe (but not in the USA) for the
same reason.
Anything with flat layers, like mica, ceramic disk, or surface mount ceramics,
isn't going to care at all about polarization for either of these reasons.
paul
