¿What is the difference among capacitors?

Here is a good place to start:

for

ute

Capacitance value for one thing. Ceramics cover from 1pF up to just short of 1uF. Then, there's some overlap as electrolytics and tants take over for larger values. Tants tend to be physically smaller than electrolytics for the same capacitance / voltage rating. For really large values, electrolytics are your only choice.

Another difference: ceramics are not polarity sensitive.

Those three are not the only types: there's polystyrene, polyester layer, monolithic ceramic .... each offering different performance in terms of precision, temperature stability, physical size, voltage rating, self-resonant frequency ....

If the capacitance and rated voltage match, it may be possible to substitute an electrolytic for a tant, or vice-versa.

for

ute

Minor nit - I use 100uF ceramics (Panasonic). Not suitable at anything approaching a high voltage, but great below 5V.

Whether devices can be substituted depends where it is used. All caps have other specifications, such as ESR (equivalent series resistance), ESL (Equivalent series inductance), leakage, ripple performance, surge performance, rms current handling and a host of other variations due to environmental conditions as well as the ones listed by Andrew.

In feedback loops esr, in particular, becomes a critical issue. See for instance, the datasheet linked here:

In the application hints, you'll find the output esr and input C - esr are considered (and important for loop stability).

The other characteristics of the various types of cap can become issues in other circuits.

Another quick example: tantalums have relatively poor surge performance (they can become spectacularly pyrotechnic), so choosing one where such a surge may exist is not as simple as looking at rms handling and capacitance.

So the answer is not a simple yes or no - as always in engineering 'It Depends'

Cheers

PeteS

There are more than that

A few that come to mind:

Polystyrene Mica Mylar Air (used to see them in old radio sets) Oil (really! I've used them) Polyester Polyphenylene sulphide Polypropylene Niobium Oxide Polymer tantalum (a variation on a theme) Then there are things like the Sanyo TPA POSCAP (Solid electrolytic, sintered tantalum anode, Polymerised organic semiconductor electrolyte)

Ceramics themselves have some variety Disc and plate Multilayer (I am sure the crowd will join in and add things I have forgotten to add or simply not come across)

Each has their pros and cons - Mylar for instance, has superb dielectric characteristics across temperature amongst other things.

Cheers

PeteS

ceramic: low incuctance, low resistance, suited to radio frequency work. tantalum low-ish resistance, compact, high-ish capacity electrolytic, moderate resistance, large capacity, cheap.

for filtering often a ceramic is paired with a tantalum or electrolytic. the ceramin deals with the sharp spikes and the other one absorbes the blunter surges.

waxed paper often used alongside air and mica caps. (obsolete)

glass (leyden jars used in some home-made tesla coils and the back half of a CRT)

I've also seen some with bitumin (I think) in them used for powerfactor correction (PFC) in some old fluorescent lights.

Bye. Jasen

Mebe. But mylars have huge amounts of parasitic inductance, making them pretty hopeless for RF applications. As someone else said, the choice of capacitor type is governed by the intended application.

Good point. This often confuses a lot of folks. They see a 100nF in parallel with a 4.7u and can't understand why the design doesn't simply specify one capacitor of equivalent value. This example illustrates that cap choice often goes way beyond just the desired value.

your joking rite?

Because 4.8u caps are hard to find ;)

--DF

I have designs that are 100% ceramic, as far as the caps go (Not all designs, but there are times it can work). Makes the power supply loop a little difficult to compensate, but definitely worth the effort. Even so, I agree on the confusion - and I still bypass my 100uF ceramics with a 0.1/0.01uF on occasion. Most cap mfrs now now give Z vs. F curves for each cap (although you may need to dig that out of their web sites) which can make life somewhat easier.

Artificial intelligence is no match for natural stupidity

Cheers

PeteS