How does Tantalum Capacitors work?

Hi,
I'm working on a school project and wanted to use tantalum capacitor. To be honest, I know how to connect but I would really like to understand what I'm doing, how it works? Before landing here I was reading this article Tantalum Capacitors - Overview and Explanation - DERF Electronics which is very easy to understand but the given information is detailed. Any detailed information or resource would be helpful !

Which are you interested in (capacitors or tantalum)? We are more equipped to talk about capacitance
since this is General Electronics, whereas Tantalum is more about a process than electronics. You might find more info on google if it’s tantalum your interested in. As a technician I can only tell you that we use tantalum when we want better quality and reliability (more stable supply voltage)
Tantalum

You are using your tablet to post, and posted the "mobile" page link as well as the annoying line wrap. :astonished:

The full page is here, and the reference to capacitors.

Might help asking specific questions about your project or situation, your question at this point can lead to an immense amount to conversation without answering your specific question.

It works just like all capacitors: it stores energy in the form of an electric field. The main difference of tantalum vs other types of capacitor is the physical size of the part.

There are numerous advantages to using tantalum capacitors over other types of capacitors. First, tantalum capacitors have a higher volumetric efficiency (CV/cc) when compared to other types of capacitors. For instance, a 10-microfarad tantalum capacitor can replace a 100-microfarad aluminum capacitor. Tantalum capacitors are easily mounted onto circuit boards, and give engineering designers the ability to place these components in closely-confined printed circuit board space, as well as utilizing tantalum capacitors' excellent power dissipation characteristics. Second, tantalum capacitors have superior frequency characteristics than many other types of capacitors, including aluminum electrolytics. A comparable CV tantalum capacitor has an ESR ten times better than an aluminum electrolytic capacitor. Third, tantalum capacitors are highly reliable – electrical performance qualities do not degrade over time. Tantalum capacitors do not lose capacitance unlike electrolytic capacitors – in fact, the shelf life for tantalums is regarded as unlimited. Fourth, tantalum capacitors don't wear out – in fact, if there is an imperfection in the dielectric layer of a tantalum, the resistance of the manganese dioxide layer will typically convert to a form that is even more resistive. The new oxide form plugs up the faulty region and results in a reduction in current flow. Finally, tantalum capacitors have an excellent wide operating range, from –55 degrees Centigrade to +125 degrees Centigrade, with a minimal amount of degradation in electrical properties throughout this range.

Main downside of tantalum over aluminium electrolytic (and which is probably why you see the latter so often): price. Tantalum caps cost a lot more.

IIRC tantalum caps may explode in fire when not used properly. Some people claim to avoid them for that reason.

Tantalum when wired the wrong way around will catch fire. Aluminium electrolytic caps tend to simply explode. I've seen both happen.

The tantalum self-extinguished quickly after disconnecting the power, just leaving some smoke and a bad smell.

The electrolytic failure was more spectacular, the cap dented when it hit the wall on the other side of the room (some 4m away, as the innards were turned into dust. This happened to me over 30 years ago, with an old paper based cap.

in both cases the caps were connected the wrong way around.

raschemmel:
For instance, a 10-microfarad tantalum capacitor can replace a 100-microfarad aluminium capacitor.

Interesting! How might it do that?

Paul__B:
Interesting! How might it do that?

Due to lower ESR and better response at higher speed. For example some regulators want "some value tantalum or some higher value aluminium cap" on output for stability.

These days few people use tantalums, their tendency to explode after a voltage transient (such as nearby
lightning), put them out of favour for one thing, and MLCC ceramic caps are available much cheaper in
much higher capacitance values, so its common to see an MLCC cap either on its own or in parallel with
a cheap aluminium electrolytic to get the same sort of performance.

Tantalum failures are high temperature metal fires, which can destroy a lot of nearby components too.
See Are tantalum capacitors safe for use in new designs? - Electrical Engineering Stack Exchange

Tantalum when wired the wrong way around will catch fire.

I'm afraid, it's far more insidious than that. A certain percentage of tantalums will operate normally at first when reverse biased, and gradually degrade until they begin to get warm. Of course, that causes them to degrade further and launches a catastrophic cascade to meltdown and fire. I know this because it was a common defect in a product I worked on. Because the reverse leakage current could be zero initially, the product could pass all production tests and go out the door in a compromised state - likely at some point it would fail and require factory repairs. Probably one of the sneakiest problems I've ever seen.

Tantalum capacitors are a subtype of electrolytic capacitors. They are made of tantalum metal which acts as an anode, covered by a layer of oxide which acts as the dielectric, surrounded by a conductive cathode. The use of tantalum allows for a very thin dielectric layer.

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