Do you connect PCB mounting holes correctly? | Keith Armstrong |
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- Опубликовано: 27 май 2024
- So, do you only connect one hole or all of them? Do you connect them directly to ground or ... ? Taken from my longer interview with Keith Armstrong.
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- Many EMC Tips to Help You Design Better PCB Boards • Many EMC Tips to Help ...
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I love the highlights format! I find 1 hour videos very difficult to follow.
agree
Agree! Interesting but difficult to get time to see them!
1 hour videos are better, contain more information
for folks looking for a good introductory text on EMC, I can recommend Keith Armstrong's book "The Physical Basis of EMC". It's a complicated subject, and there are probably a half dozen books that would be extremely helpful, but I think this is easily one of the best books.
That was fascinating. I didn't realize how these higher frequency resonances are (should be) impacting design of even basic consumer electronics.
Love the vids and the shorter format ! I hope you can sum things up at the end of the videos. Great videos keep posting 👍
Ever since I figured out that ultra annoying hum in my amplifier comes from the GND loop, i tend to isolate the screws altogether. Now I hope I'll learn doing it the proper way.
this highlights are greats, thanks
Perfect! Really informative.
very informative, thank you!
Thanks a lot. I was eager to learn about this topic.
good stuff as always :D
In some cases where I have sub ns rise time signals I can put inductors to the chassis mounting holes. Then I will remove the solder mask around the mounting hole to solder it to see what works best.
Hi Robert, I connect the 0V on a board to the chassis via a capacitor in parallell with a high impedance bleeder resistor for being able to handle esd-pulses. I understand what you mean by placing a resistor here instead with the purpose to dampen out oscillations. How are your thoughts regarding this? Do you think I should place a resistor in series with my capacitor then? Will I then be able to handle the esd-pulse? Thanks for great videos! /Tomas
I’m in the automotive ECU design world, I use a 10k to 33k bleeder resistor, the ESD/EMI capacitor, and a small (2.2 to 10 ohm) series damping resistor. The trickiest part is to damp the resonance but not create too much impedance for the BCI testing or ESD, I use ESD rated parts here, and the very low value damping resistor does ok in the ESD testing I’ve done on this network. The bleeder resistor is a pretty low value here but the voltages are low. This has worked for me, though the resonant issue I face is not high frequency but rather in the 100 MHz range, it’s the wiring harness loop size which is usually a metre or two long.
@@dale116dot7 Thanks for your share! This is also how I am thinking!
I am confused now. I got the impression like with connecting a USB or other connectors to a board, to connect the shield of a cable or connector to the encasing of the device, not to the reference plane. Analog i thought to not connect the mounting hole to the reference plane; can a metal screw act like an antenna or stub? And is this the reason for the 1/10 lambda rule?
It's all about EMC. The space between conductive planes can be seen as a cavity resonator that generates radiation interference. The conductive posts can conduct the received emissions that causes conductive interference to the reference plane of the PCBs. Damping or filtering the unwanted resonance can significantly reduce the effect of the radiation.
It can of course cause the potential difference between the reference planes, which would be a problem when interface the signals between boards. It is not recommended to directly connect ground in this case as it may cause grounding loop problem. Differential signal can be an ultimate solution in this case.
Something like grounding and earthing involves some knowledge and there are still some research about it. I recommend a book called "The Circuit Designer's Companion".
11:14 sorry sir we don't make 18awg vias we only go up to 0.3mm dia.