[LIVE] How to Achieve Proper Grounding - Rick Hartley - Expert Live Training (US)

That video is good for the water like wave explanation that is a very useful lens. If you want a more in-depth explanation, particularly how the field is in the dielectric and the wires/traces are simply the wave guide, this long presentation by Rick Hartley will help move to the next level. ▶ this video The dramatic shift in behavior above the audio frequency range is where the water wave lens starts to fall down IMHO. I was looking at my brothers memory card from a Cray 1a the other day and that video popped in my head. They had the timing traces snaking through several flat-pack chips legs. No wonder they had to move from parity to Hamming code even with exclusively using differential twisted pairs between modules.

in “Oliver Heaviside and the theory of transmission lines (2021)” · View on HN

This is advanced level PCB design. You need to know proper grounding and differential pairs and length matching to accomplish what is listed in this article. These are very difficult topics, but this 2 hour video should give you an idea of what's going on here: ▶ this video -------- If this is too much for you, then instead stick to microcontrollers and other sub-100Mhz or sub-20Mhz projects. But 500MHz and above that requires length matching with controlled impedances is waaaayyyyy outside the scope for a beginner designer. --------- Beginner design is easier at 20MHz or so. The faster your signals, the more susceptible to noise they are. Those 500MHz+ Linux MPUs may fail to boot or fail spuriously if you make grounding / noise / EMC errors. And it's pretty difficult to explain to a beginner what is going on physically. The PCB board itself needs to be seen as parasitic capacitors, inductors and resistors (especially around Vias, between layers and other elements). But these 500Mhz or so processors here in this blogpost are still easier than Ghz+ chips. ------ The example I always like to point out: 2.4GHz wavelength is just a couple of cm long. That means any trace of ~centimeters can accidentally turn into a Bluetooth / WiFi antenna, which would inject a ton of noise into your circuit (or conversely: 'Throw' your electrons out like a Bluetooth / WiFi antenna). That's why faster speeds are harder. 900Mhz and slower needs an antenna over 30cm long, so staying below this means eve

in “So you want to build an embedded Linux system?” · View on HN

The professionals use PCB-design software with physical modeling / FEA to calculate estimates to all of the important parameters of the circuit board (including how much trace lengths matter... but also board-capacitance, resistances, and resonance frequencies of the board itself, etc. etc.) In contrast, we hobbyists deal with "rules of thumb", because none of us will spend $4000+ on professional PCB software that run these calculations for us. And furthermore, we aim very conservative because its very difficult to debug a PCB layout issue... as we hobbyists are functionally blind to all of these issues (ex: trace inductance, trace capacitance, or other issues). I think spending a good bit of time on PDN / grounding / etc. etc. study is very worth your while. ▶ this video 2+ hour talk on just the issue of good "grounding" design in PCBs, but it does relate to this issue of capacitors, trace-lengths and the like. I feel like you'd benefit from this talk. The "correct" way of thinking is exceptionally complex, far more complex than what is taught in colleges. But you have all the basic ideas thanks to the old rules of thumb. You just need to take the next step to see what the problems are. -------- And as you'll see, traces on the same side of a board are cake. Its things like vias that actually wreck you.

in “I like the RP2040” · View on HN

The article is not that good, but whatever. I am new to electronics myself and quite fascinated how has the art progressed in the past hundred or so years. There are people remembering "we were doing it wrong". Incredible. Anyway, if you are interested in signals traveling inside those cute green multi-GHz boards you make your living off, go watch Rick Hartley. ▶ this video (How to Achieve Proper Grounding) [link] (What your Differential Pairs Wish You Knew)

in “The Mysterious 50 Ohm Impedance: Where It Came from and Why We Use It” · View on HN

> so wouldn't it be better to put power/ground on the outer layers and keep signals in the middle? Signals must never cross a break or split in the plane they're referencing (usually 0V or ""ground""). This creates huge EMI problems. Your proposal would have signals on layer 2 crossing a split in the ground plane on layer 1 (that split caused by power traces). Some interesting material on the subject: [link] [link] ▶ this video [link]

in “The magic of DC-DC voltage conversion (2023)” · View on HN