A few years ago, I started using solid aluminum polymer capacitors for most projects involving power conversion or digital circuits, either new designs or repairs.
Somehow, I never thought about measuring the parameters of this capacitor type. By hazard, one day I measured a 100 uF / 25 V Kemet polymer capacitor, and it gave a reading of exactly 100.1 uF. That made me curious enough to start collecting some data.
Unfortunately, at the moment, I don't have that many polymer capacitors in stock. Normally, I buy capacitors only when I need them. And generally speaking, I am so excited to advance with my projects that I will use them within 24 to 48 hours from their arrival. But I think I have enough to start the database.
I plan to regularly update this article as long as I order new parts. In general, I use OS-CON, Kemet, and Nichicon, in this particular order. Sometimes, I use capacitors from other reputable brands as well.
Disclaimer: As before, I am in no way affiliated with any brands mentioned in this article, nor do I gain anything from them for writing this essay. I just strive to use the best electronic components for my hobby projects. Thus, this kind of research is mandatory.
Without further talk, let's get straight to the results. Once again, I will use the Hewlett-Packard 4276A LCZ Meter, letting it warm up for half an hour before taking the measurements.
Even though the settings are stored in battery back-up memory, I re-zeroed the unit with both open and shorted test terminals. The DC bias was turned off and the measurements were taken at 120 Hz.
I took the readings during a hot summer evening, using the old way of noting down on paper whatever the instrument displayed. During warm-up, I repeatedly took measurements of the same 150 uF / 400 V standard electrolytic capacitor that consistently reported 130 uF. Normally I use a hand selected 1 uF / 50 V film capacitor that gives a capacitance reading of exactly 1000 nF and an ESR of 0 Ω. But I was lazy enough to go to my parts drawer and just took whatever I had around. As a side note, this capacitor is going to be installed in the IBM eServer xSeries 330 power supply.
Once the capacitance and ESR display readings stopped fluctuating, I started measuring the polymer capacitors. I sorted the collected data by capacitors manufacturer and series so that we can have a better overview.
I will occasionally update this article, as I order new capacitors for my projects.
The Kemet A759 series designates long life capacitors that can withstand 125 °C. I tend to use these mostly in power conversion circuits.
KEMET A759 SERIES CAPACITOR DATA | |||||
---|---|---|---|---|---|
Brand | Type | Style | Rating | Capacity | ESR |
Kemet | Polymer | Radial | 10 uF / 63 V | 10.85 uF | 1.52 Ω |
Kemet | Polymer | Radial | 10 uF / 50 V | 11.33 uF | 1.51 Ω |
Kemet | Polymer | Radial | 10 uF / 50 V | 11.35 uF | 1.57 Ω |
Kemet | Polymer | Radial | 10 uF / 50 V | 11.45 uF | 1.52 Ω |
Kemet | Polymer | Radial | 10 uF / 50 V | 11.51 uF | 1.61 Ω |
Kemet | Polymer | Radial | 10 uF / 50 V | 11.52 uF | 1.57 Ω |
Kemet | Polymer | Radial | 10 uF / 50 V | 11.76 uF | 1.51 Ω |
Kemet | Polymer | Radial | 10 uF / 50 V | 11.96 uF | 1.52 Ω |
Kemet | Polymer | Radial | 10 uF / 50 V | 11.75 uF | 1.51 Ω |
Kemet | Polymer | Radial | 10 uF / 50 V | 11.45 uF | 1.52 Ω |
The Kemet A758 series offers long life capacitors that can work up to 105 °C. I use these in power conversion circuits and general computer-related hardware. These A758 capacitors are miniature variants of the A755 series.
KEMET A758 SERIES CAPACITOR DATA | |||||
---|---|---|---|---|---|
Brand | Type | Style | Rating | Capacity | ESR |
Kemet | Polymer | Radial | 680 uF / 10 V | 741 uF | 0.02 Ω |
Kemet | Polymer | Radial | 680 uF / 10 V | 742 uF | 0.02 Ω |
Kemet | Polymer | Radial | 100 uF / 16 V | 110 uF | 0.08 Ω |
Kemet | Polymer | Radial | 22 uF / 25 V | 23.32 uF | 1.05 Ω |
Kemet | Polymer | Radial | 22 uF / 25 V | 23.42 uF | 0.87 Ω |
Kemet | Polymer | Radial | 22 uF / 25 V | 23.37 uF | 0.93 Ω |
Kemet | Polymer | Radial | 22 uF / 25 V | 23.17 uF | 0.92 Ω |
Kemet | Polymer | Radial | 22 uF / 25 V | 23.20 uF | 0.90 Ω |
Kemet | Polymer | Radial | 22 uF / 25 V | 23.23 uF | 0.91 Ω |
Kemet | Polymer | Radial | 10 uF / 25 V | 10.95 uF | 2.13 Ω |
Kemet 755 series capacitors have a long life at up to 105 °C, and are advertised as good for LED driver power supplies, general computer-related power supply designs, and medical equipment. And that's why I use them for; well, except for medical equipment, as I don't have any experience with that.
KEMET A755 SERIES CAPACITOR DATA | |||||
---|---|---|---|---|---|
Brand | Type | Style | Rating | Capacity | ESR |
Kemet | Polymer | Radial | 100 uF / 25 V | 103 uF | 0.13 Ω |
Kemet | Polymer | Radial | 100 uF / 25 V | 103 uF | 0.13 Ω |
The Kemet A750 series designates radial capacitors with an operating temperature up to 105 °C, and are typically used in the computer hardware field, both server and consumer grade.
KEMET A750 SERIES CAPACITOR DATA | |||||
---|---|---|---|---|---|
Brand | Type | Style | Rating | Capacity | ESR |
Kemet | Polymer | Radial | 470 uF / 25 V | 530 uF | 0.06 Ω |
Kemet | Polymer | Radial | 47 uF / 25 V | 50.15 uF | 0.34 Ω |
Kemet | Polymer | Radial | 47 uF / 25 V | 50.62 uF | 0.32 Ω |
Kemet | Polymer | Radial | 47 uF / 25 V | 51.14 uF | 0.30 Ω |
Kemet | Polymer | Radial | 47 uF / 25 V | 51.85 uF | 0.32 Ω |
Kemet | Polymer | Radial | 47 uF / 25 V | 51.92 uF | 0.32 Ω |
Kemet | Polymer | Radial | 47 uF / 25 V | 52.01 uF | 0.32 Ω |
Kemet | Polymer | Radial | 47 uF / 25 V | 52.43 uF | 0.30 Ω |
Kemet | Polymer | Radial | 47 uF / 25 V | 51.68 uF | 0.30 Ω |
Kemet | Polymer | Radial | 47 uF / 25 V | 51.44 uF | 0.31 Ω |
Kemet | Polymer | Radial | 47 uF / 25 V | 51.72 uF | 0.29 Ω |
Kemet | Polymer | Radial | 47 uF / 25 V | 51.98 uF | 0.32 Ω |
Kemet | Polymer | Radial | 47 uF / 25 V | 51.59 uF | 0.31 Ω |
The FP series from Nichicon stands for functional polymer. The RNL series designates large sized, high capacitance parts with operating temperatures of up to 105 °C. I use these for power supply repairs and computer mainboard restoration.
NICHICON RNL SERIES CAPACITOR DATA | |||||
---|---|---|---|---|---|
Brand | Type | Style | Rating | Capacity | ESR |
Nichicon | Polymer | Radial | 1200 uF / 16 V | 1156 uF | 0.03 Ω |
OS-CON SEP capacitors are rated for around 3,000 h. at 105 °C. I use these for computer-related hardware repairs, and new designs.
OS-CON SEP SERIES CAPACITOR DATA | |||||
---|---|---|---|---|---|
Brand | Type | Style | Rating | Capacity | ESR |
OS-CON | Polymer | Radial | 22 uF / 20 V | 23.50 uF | 0.45 Ω |
OS-CON SEPC capacitors are advertised as super low ESR (5 mΩ max.) and are available up to 2700 uF at 2.5 V. Capacitors of 470 uF and below are available up to 16 V. These are my go-to capacitors for all digital circuits, especially computer-grade hardware.
OS-CON SEPC SERIES CAPACITOR DATA | |||||
---|---|---|---|---|---|
Brand | Type | Style | Rating | Capacity | ESR |
OS-CON | Polymer | Radial | 1000 uF / 6 V | 908 uF | 0.03 Ω |
OS-CON | Polymer | Radial | 1000 uF / 6 V | 913 uF | 0.03 Ω |
OS-CON | Polymer | Radial | 1000 uF / 6 V | 901 uF | 0.03 Ω |
OS-CON | Polymer | Radial | 1000 uF / 6 V | 911 uF | 0.03 Ω |
OS-CON | Polymer | Radial | 1000 uF / 6 V | 903 uF | 0.03 Ω |
OS-CON | Polymer | Radial | 1000 uF / 6 V | 910 uF | 0.03 Ω |
OS-CON | Polymer | Radial | 1000 uF / 6 V | 890 uF | 0.03 Ω |
OS-CON | Polymer | Radial | 1000 uF / 6 V | 885 uF | 0.03 Ω |
OS-CON | Polymer | Radial | 1000 uF / 6 V | 890 uF | 0.03 Ω |
OS-CON | Polymer | Radial | 1000 uF / 6 V | 889 uF | 0.03 Ω |
OS-CON | Polymer | Radial | 820 uF / 2.5 V | 797 uF | 0.39 Ω |
OS-CON | Polymer | Radial | 820 uF / 2.5 V | 759 uF | 0.40 Ω |
OS-CON | Polymer | Radial | 820 uF / 2.5 V | 764 uF | 0.40 Ω |
OS-CON | Polymer | Radial | 820 uF / 2.5 V | 720 uF | 0.37 Ω |
OS-CON | Polymer | Radial | 820 uF / 2.5 V | 776 uF | 0.38 Ω |
OS-CON | Polymer | Radial | 470 uF / 16 V | 475 uF | 0.04 Ω |
OS-CON | Polymer | Radial | 470 uF / 16 V | 460 uF | 0.04 Ω |
OS-CON | Polymer | Radial | 470 uF / 16 V | 475 uF | 0.05 Ω |
OS-CON | Polymer | Radial | 470 uF / 16 V | 468 uF | 0.04 Ω |
OS-CON | Polymer | Radial | 470 uF / 16 V | 489 uF | 0.04 Ω |
OS-CON | Polymer | Radial | 470 uF / 16 V | 489 uF | 0.04 Ω |
OS-CON | Polymer | Radial | 470 uF / 16 V | 491 uF | 0.04 Ω |
OS-CON | Polymer | Radial | 470 uF / 16 V | 484 uF | 0.04 Ω |
OS-CON | Polymer | Radial | 470 uF / 16 V | 479 uF | 0.04 Ω |
OS-CON | Polymer | Radial | 470 uF / 16 V | 472 uF | 0.05 Ω |
OS-CON | Polymer | Radial | 470 uF / 16 V | 479 uF | 0.04 Ω |
OS-CON | Polymer | Radial | 470 uF / 6 V | 445 uF | 0.03 Ω |
OS-CON | Polymer | Radial | 470 uF / 6 V | 465 uF | 0.03 Ω |
OS-CON | Polymer | Radial | 470 uF / 6 V | 453 uF | 0.03 Ω |
OS-CON | Polymer | Radial | 470 uF / 6 V | 452 uF | 0.03 Ω |
OS-CON | Polymer | Radial | 470 uF / 6 V | 466 uF | 0.03 Ω |
OS-CON | Polymer | Radial | 470 uF / 6 V | 463 uF | 0.03 Ω |
OS-CON | Polymer | Radial | 470 uF / 6 V | 466 uF | 0.03 Ω |
OS-CON | Polymer | Radial | 470 uF / 6 V | 468 uF | 0.03 Ω |
OS-CON | Polymer | Radial | 470 uF / 6 V | 456 uF | 0.03 Ω |
OS-CON | Polymer | Radial | 470 uF / 6 V | 461 uF | 0.03 Ω |
OS-CON | Polymer | Radial | 470 uF / 6 V | 456 uF | 0.03 Ω |
OS-CON | Polymer | Radial | 470 uF / 6 V | 473 uF | 0.03 Ω |
OS-CON | Polymer | Radial | 470 uF / 6 V | 462 uF | 0.03 Ω |
OS-CON | Polymer | Radial | 470 uF / 6 V | 468 uF | 0.03 Ω |
OS-CON | Polymer | Radial | 470 uF / 6 V | 481 uF | 0.03 Ω |
OS-CON | Polymer | Radial | 470 uF / 6 V | 458 uF | 0.03 Ω |
OS-CON | Polymer | Radial | 470 uF / 6 V | 436 uF | 0.03 Ω |
OS-CON SEPF capacitors come in large capacitance, high voltage flavours. As above, I use these for computer hardware repairs and new designs. ESR is a bit higher than that of SEPC series, but still low enough for switched mode power conversion circuits.
OS-CON SEPF SERIES CAPACITOR DATA | |||||
---|---|---|---|---|---|
Brand | Type | Style | Rating | Capacity | ESR |
OS-CON | Polymer | Radial | 120 uF / 20 V | 113 uF | 0.15 Ω |
OS-CON | Polymer | Radial | 120 uF / 20 V | 111 uF | 0.15 Ω |
OS-CON | Polymer | Radial | 120 uF / 20 V | 109 uF | 0.15 Ω |
OS-CON | Polymer | Radial | 120 uF / 20 V | 112 uF | 0.18 Ω |
OS-CON | Polymer | Radial | 56 uF / 25 V | 55.65 uF | 0.32 Ω |
OS-CON | Polymer | Radial | 56 uF / 25 V | 56.91 uF | 0.32 Ω |
Even though I plan to add more data, the overall picture becomes clear. These polymer capacitors are good. I've had some of the smaller capacity Kemet parts since 2019, and they still measure well within their rated specifications.
The process of collecting and sorting all this data was interesting. I was expecting lower capacitance values, as this appears to be common practice for standard electrolytic capacitors, even for those coming from quality brands. But the readings were pretty consistent. At least almost all Kemet and OS-CON capacitors have either spot on, or close to the advertised capacitance.
For some reason, the Nichicon capacitors report a slightly lower capacitance value. Alternately, some Kemet capacitors have a higher capacity than what's printed on the can.
The low ESR is no wonder as it was quite expected. I randomly analyzed the datasheets for some of these capacitors and the ESR values match or are lower than advertised.
I hope you found this research useful.
This essay is provided as-is and is not for commercial purposes. It reflects my experiments and research and should be treated as such. I release my work to the public for educational purposes. I did all this at my own expense and in my free time. So if you like my work, or find it useful or inspiring for your projects, please consider making a donation.
Copyright © 2004- Alexandru Groza
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