I'm not sure what you're describing. Can you link to a pic of one of these caps? But in general, nothing lower than 1.0uF in value is likely to be polarized, and any polarized cap will need to have a polarity marking for at least one of the leads. Smallest polar cap I've ever seen was a 0.47uF electrolytic. You'll sometimes find a dot or band on a small non-polar cap, but that typically indicates the 'outer' foil of the cap so that it can be installed in the most efficient orientation (outer foil to ground, in an RF bypass, etc). On Sun, Sep 27, 2015 at 1:03 PM, Noel Chiappa <jnc at mercury.lcs.mit.edu> wrote:

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