Let's Talk Capacitors

[speakerguy79]

OK, I am a COMPLETE newbie to *real* electronics. I'm an EE, but unfortunately all that means these days is that I can code and know some basics about electricity. I'm starting to play around with PCB design programs and would like to make some simple projects - active crossovers at first, progressing from there to digital stuff eventually. One of the things I find bewildering is the array of capacitor types.

So... the basic capacitor types:

Electrolytic - chemical caps. Based on some oxide layer forming on an anode IIRC, which requires a certain voltage to make form, which means they have a voltage offset. Useful for big values, DC work.

Film caps - polystyerene/propylene/whatever - I use them a lot in speakers. A generally good capacitor? I've only experience with radial leaded caps, no smt stuff. No idea what use they are in actual circuits other than loudspeaker XO's.

Ceramics - mainly used for bypass stuff? Are SMT ceramics/multi-layer ceramics as good as the disc kind? I think they are good at HF but small values for their size.

Tantalum - I have no idea what these are for

Mica - ditto

'Super' capacitors - the new ones that do 1000F at like 2.5V - I also have no idea what these are for, but they are expensive

Teflon - film cap I guess. Uses?

I know there are more, but I'm really just looking for someone to say "these are good for X" or "these are sucky for Y". Also, are SMT parts as good as ones with leads? I would like to do SMT stuff to keep board size down but not if audio quality would suffer.

Thanks!

[SY]

Do not hesitate, run right out and buy Bob Pease's "Troubleshooting Analog Circuits," which has answers to most of your questions and much, much more. Great for adding the practical knowledge of a bench guy to the very theoretical orientation of modern academic EE.

[jarthel]

Originally posted by speakerguy79


Film caps - polystyerene/propylene/whatever - I use them a lot in speakers. A generally good capacitor? I've only experience with radial leaded caps, no smt stuff. No idea what use they are in actual circuits other than loudspeaker XO's.

polypropylene are used extensive in amplifier circuits. teflon has the same uses as well.

polypro is good. teflon even better. but some has said teflon might not be suitable in a particular circuit so this varies.

you also have paper-in-oil which are mainly used in tube circuits.

[jarthel]

also what are solid-state capacitors?

I found this on Gigabyte's website (the motherboard manufacturer) and searching the internet gave no useful sites.

thank you.