On Dec 1, 11:27*pm, "Ross, NS7F" wrote:
Dear List,
I am looking for your wisdom and lore regarding uses for some of the
more exotic capacitors found in my junque-box. I have been a ham for a
whole sunspot cycle now. I know what an NP0/C0G capacitor is and when
to use it, I know electrolytics, tantalum, and about the use of
Temperature Compensating capacitors. I have checked the usual places
(books, ARRL TIS, the archives of this list, etc) and none of these
resources tell me several important things: what they look like and
where would I use them in ham homebrew circuits. Here is my list:

UNKNOWN TYPE AND APPLICATION:
1. Blue, really shiny, flat, and small like a disc ceramic.

Probably is a disc ceramic :-). Some makers use blue on their higher-
voltage disk ceramics. Labeling will probably tell voltage and
capacitance.

2. Orange and shiny- definitely not electrolytic or tantalum. Both
bulgy and flattish.

3. Green and shiny- both bulgy and flattish. (I've heard these are
either mylar or polyester film. How do I tell them apart?)

4. Dark orange (maybe brownish?) and bulgy.

5. Yellow rectangular blocks.

All of the above are probably film capacitors of some kind or another.
Color doesn't mean much except maybe to an audiofile.

KNOWN TYPE, UNKNOWN APPLICATION
6. Labeled "monolithic dip"- what do I use these for?

Widely used ceramic capacitors. Small values are good for RF, larger
for bypass. Depending on the dielectric may not be worthwhile for
audio.

7. "Mallory DC Film" (250V)- what do I use these for?

These are higher voltage film polypropylene capacitors.

8. What's the difference between the following three types of mica
capacitors?
* Dipped silver mica
* Old-style micas (colored dots and physically large rectangular
blocks)
* Modern, not dipped-silver micas

All are potentially useful where you need a low-dissipation capacitor.
The old-style micas less so. Sometimes even if it's a rectangular
package with colored dots, they are just ceramic and not micas.

For many modern purposes, modern C0G ceramics will be superior (better
lower tempco) to the long-recommended silver micas.

Tim N3QE