Small glass capacitors polarized?

[tony duell]

> 
> 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?

I am pretty sure they are not polarised, you can fit them either way.

In general capacitors under 1uF are not polarised (I _have_ seen 0.22uF and 0.47uF
tanatulum electrolytics which are, of course, polarised, but they are uncommon). 
Anything over 100uF is very likely to be polarised. Between 1uF and 100uF they are 
likely to be polarised, but non-polarised ones of those values are not uncommon 
particularly not in audio applications (loudspeaker crossover networks, for example).

Incidentally, what are you using those capacitors for? Why not some other type? And
doesn't the supplier offer a data sheet?

-tony