# The Spark Gap - Episode 30

- Show: [The Spark Gap](https://hardwarepodcasts.com/podcast/the-spark-gap)
- Published: 2015-04-08
- Length: 57m
- Page: https://hardwarepodcasts.com/podcast/the-spark-gap/2015-04-08-the-spark-gap-episode-30
- Listen: https://thesparkgap.net/the-spark-gap-episode-30

## Summary

Hosts Carl and Corey discuss methods for switching and routing power in embedded electronics, starting with the limitations of microcontroller GPIO pins and the distinction between high-side and low-side switching. They analyze the trade-offs between P-channel and N-channel MOSFETs, explaining why N-channel devices are often preferred for high-side switching when paired with gate drivers to overcome threshold voltage issues. The conversation covers the problem of body diodes in MOSFETs, the use of dual-FET configurations or solid-state relays (SSRs) to block reverse current, and the specific advantages and disadvantages of mechanical relays regarding contact resistance, capacitance, and signal integrity.

## Chapters

- [0:00](https://hardwarepodcasts.com/podcast/the-spark-gap/2015-04-08-the-spark-gap-episode-30#t=0) Introduction and Microcontroller Limitations
- [3:05](https://hardwarepodcasts.com/podcast/the-spark-gap/2015-04-08-the-spark-gap-episode-30#t=185) High-Side vs Low-Side Switching Basics
- [10:18](https://hardwarepodcasts.com/podcast/the-spark-gap/2015-04-08-the-spark-gap-episode-30#t=618) MOSFET Selection: P-Channel vs N-Channel
- [16:01](https://hardwarepodcasts.com/podcast/the-spark-gap/2015-04-08-the-spark-gap-episode-30#t=961) Gate Drivers for High-Side N-Channel Switching
- [28:34](https://hardwarepodcasts.com/podcast/the-spark-gap/2015-04-08-the-spark-gap-episode-30#t=1714) Body Diodes and Dual-FET Solutions
- [36:05](https://hardwarepodcasts.com/podcast/the-spark-gap/2015-04-08-the-spark-gap-episode-30#t=2165) Solid State Relays (SSRs) vs MOSFETs
- [44:08](https://hardwarepodcasts.com/podcast/the-spark-gap/2015-04-08-the-spark-gap-episode-30#t=2648) Mechanical Relays and Signal Integrity

## Topics

- [Analog & power electronics](https://hardwarepodcasts.com/topic/analog-and-power-electronics)
- [Microcontrollers & dev platforms](https://hardwarepodcasts.com/topic/microcontrollers-and-platforms)
- [PCB design & layout](https://hardwarepodcasts.com/topic/pcb-design)

## Most relevant to

makers and hobbyists

## Mentioned

- DigiKey (company)
- Bosch relay (product)
- Reed relay (product)
- Triac (chip)

## Related episodes from other shows

- [Moore's Law, GaN and SiC devices - Gallimaufry GaN Gabble](https://hardwarepodcasts.com/podcast/the-amp-hour/2011-09-20-moores-law-gan-and-sic-devices-gallimaufry-gan-gabble) (The Amp Hour)
- [Mute Button Discipline](https://hardwarepodcasts.com/podcast/the-amp-hour/2022-05-16-mute-button-discipline) (The Amp Hour)
- [Ep. 6 | Crucial Trade-Offs in Automotive Power Design with Tesla and Vicor](https://hardwarepodcasts.com/podcast/moores-lobby/2020-07-23-ep-6-crucial-trade-offs-in-automotive-power-design-with-tesla-and-vicor) (Moore's Lobby)
- [Inventing the Power MOSFET with Alex Lidow](https://hardwarepodcasts.com/podcast/the-amp-hour/2026-03-20-inventing-the-power-mosfet-with-alex-lidow) (The Amp Hour)
- [Microcontroller Showdown: Selecting the Best One for Your Project](https://hardwarepodcasts.com/podcast/predictable-designs-podcast/2023-01-04-microcontroller-showdown-selecting-the-best-one-for-your-project) (Predictable Designs Podcast)

## Citing this page

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