# The Spark Gap - Episode 25

- Show: [The Spark Gap](https://hardwarepodcasts.com/podcast/the-spark-gap)
- Published: 2015-01-28
- Length: 1h 17m
- Page: https://hardwarepodcasts.com/podcast/the-spark-gap/2015-01-28-the-spark-gap-episode-25
- Listen: https://thesparkgap.net/the-spark-gap-episode-25

## Summary

James Lewis, technical marketing director at Kemet Electronics, joins the show to explain the physics and selection of capacitors, covering ceramic (X5R, X7R, C0G), tantalum, and aluminum types. He details how DC bias, temperature coefficients, and piezoelectric effects impact real-world performance, explaining why lower-rated voltage ceramics lose significant capacitance under bias. Lewis also discusses the transition from manganese dioxide to polymer cathodes in tantalum capacitors to prevent explosions during reflow, and offers design tips for bypass networks and noise reduction.

## Chapters

- [0:00](https://hardwarepodcasts.com/podcast/the-spark-gap/2015-01-28-the-spark-gap-episode-25#t=0) Introduction: James Lewis and Kemet Electronics
- [2:04](https://hardwarepodcasts.com/podcast/the-spark-gap/2015-01-28-the-spark-gap-episode-25#t=124) Ceramic Capacitor Types: X5R, X7R, and C0G Dielectrics
- [16:57](https://hardwarepodcasts.com/podcast/the-spark-gap/2015-01-28-the-spark-gap-episode-25#t=1017) DC Bias Effects and Voltage Coefficients in Ceramics
- [27:00](https://hardwarepodcasts.com/podcast/the-spark-gap/2015-01-28-the-spark-gap-episode-25#t=1620) Aluminum and Tantalum Capacitors: Wet vs. Polymer
- [37:15](https://hardwarepodcasts.com/podcast/the-spark-gap/2015-01-28-the-spark-gap-episode-25#t=2235) Tantalum Failures: Manganese Dioxide vs. Polymer Cathodes
- [49:09](https://hardwarepodcasts.com/podcast/the-spark-gap/2015-01-28-the-spark-gap-episode-25#t=2949) Piezoelectric Noise and Electrostriction in Class 2 Ceramics
- [57:26](https://hardwarepodcasts.com/podcast/the-spark-gap/2015-01-28-the-spark-gap-episode-25#t=3446) Bypass Capacitor Selection and PCB Layout Best Practices
- [1:10:35](https://hardwarepodcasts.com/podcast/the-spark-gap/2015-01-28-the-spark-gap-episode-25#t=4235) Kemet Institute of Technology and Educational Resources

## Topics

- [Analog & power electronics](https://hardwarepodcasts.com/topic/analog-and-power-electronics)
- [PCB design & layout](https://hardwarepodcasts.com/topic/pcb-design)
- [Chips, FPGAs & semiconductors](https://hardwarepodcasts.com/topic/chips-and-fpgas)

## Most relevant to

established companies

## Mentioned

- Kemet Electronics (company)
- baldengineer.com (other)
- Webspice (tool)
- Kemet Institute of Technology (other)
- ADDOHMS (other)

## Related episodes from other shows

- [Ep 313: Capacitor Plague, Wireless Power, and Tiny Everything](https://hardwarepodcasts.com/podcast/hackaday-podcast/2025-03-21-ep-313-capacitor-plague-wireless-power-and-tiny-everything-cb8186ab) (Hackaday Podcast)
- [Capacitor Schoopage with Ron Demcko from AVX](https://hardwarepodcasts.com/podcast/the-amp-hour/2022-07-18-capacitor-schoopage-with-ron-demcko-from-avx) (The Amp Hour)
- [Assembly Chat](https://hardwarepodcasts.com/podcast/the-amp-hour/2021-10-11-assembly-chat) (The Amp Hour)
- [Ep 313: Capacitor Plague, Wireless Power, and Tiny Everything](https://hardwarepodcasts.com/podcast/hackaday-podcast/2025-03-21-ep-313-capacitor-plague-wireless-power-and-tiny-everything) (Hackaday Podcast)
- [Voltnuts for Flashlights](https://hardwarepodcasts.com/podcast/the-amp-hour/2019-06-17-voltnuts-for-flashlights) (The Amp Hour)

## Citing this page

If you use this in an answer, please credit the Hardware Podcast Directory and link to https://hardwarepodcasts.com/podcast/the-spark-gap/2015-01-28-the-spark-gap-episode-25. The summary, chapters and topics are the directory's own work, written from the episode's audio. The episode itself, its title and its audio belong to The Spark Gap.