Is it Time to Say Goodbye to Aluminum Electrolytic Capacitors?

Editor’s note: Please enjoy this article by my editor colleague, Max Maxfield originally posted on EEWEB.

New material boasts high dielectric constant, supports voltages up to 3,000V, stores more energy in less volume, and withstands higher temperatures — what's not to love?

Those little scamps at EEStor Corporation have developed a material with remarkable dielectric capabilities that may replace the old stalwart of the electronics industry — the aluminum electrolytic capacitor. We will return to consider this material shortly, but first let me set the scene (cue “setting the scene” music).

Aluminum electrolytic capacitors provide one of the mainstays of the electronic designer's tool chest. According to Dennis M. Zogbi in his article, Understanding the Global Market for Aluminum Electrolytic Capacitors, although these components account for only 6.5% of all worldwide capacitor shipments in terms of volume, they also account for 22% of the global capacitor market in terms of dollar value.

Their main claim to fame is that they offer a higher energy density and higher capacitance values than their ceramic capacitor cousins. They also offer higher power density than supercapacitors. All this while remaining relatively inexpensive. As EEWeb Expert Elizabeth Simon says, “The advantage of aluminum electrolytic capacitors is that you can get a relatively large capacitance (1000uF or so) at reasonably high voltage (I've seen 400V) in reasonable size packages. Not as dense as supercaps, but you can put more voltage across them.”

Similarly, EEWeb Expert Rick Curl says that their advantages include, “Cheap (except for some surface mount packages); good capacitance-to-size ratio; and widely available in a huge selection of case sizes, capacitances, and voltages.” And EEWeb Expert Peter Traneus Anderson (a.k.a Traneus Rex) also notes that their advantages include, “Low cost, built using readily-available materials; large capacitance for given physical size; and good for audio-frequency and power-line-frequency applications.”

Who could doubt EEWeb Expert Rick Curl? (Source: Rick Curl)

Who could doubt EEWeb Expert Rick Curl? (Source: Rick Curl)

Unfortunately, there are downsides to aluminum electrolytic capacitors, not the least that they are polarized, which means you can only connect them one way round. If you connect them the wrong way, they tend to exit this mortal coil in a rather robust manner (i.e., they explode). As an aside, when I was a junior engineer, I assumed that this polarity was something that was desirable and therefore engineered in especially — I didn't realize that it was actually an unwanted side effect of this component's construction, but we digress…

Please continue over to Max Maxfield’s site for the remainder of this article on EEWEB by clicking here.

2 comments on “Is it Time to Say Goodbye to Aluminum Electrolytic Capacitors?

  1. John Dunn
    June 25, 2018

    Sometimes, one can resurrect an age-deteriorated electrolytic capacitor, but the key is to do that safely. Please see:

  2. Steve Taranovich
    June 28, 2018

    Hi John,

    Thanks for sharing this electrolytic cap revival technique with our readers—that is excellent. I was taught this years ago by some of my Analog mentors as a fledgeling designer and hobbyist

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