Questions tagged [shielding]
Questions regarding shielding devices against noise, interference, or ESD. Not to be confused with arduino-shield.
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1answer
97 views
USB shield for analog and digital ground?
I'm new to Mixed-signal design and I'm having trouble deciding how to connect my digital and analog ground. I'm doing a 4 layer design, so I have a split ground plane.
As I understand, since I'm ...
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2answers
45 views
Help Shielding RF Anechoic Chamber - FM Stations
a collegue and I acquired a surplus small anechoic chamber (8 ft x 8 ft) for making some pre compliance test measurements, and we're running into the issue of FM Stations being only attenuated around ...
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3answers
88 views
Using shielded audio cable for potentiometer sensor
I'm trying to measure a potentiometer from an Arduino's ADC. The potentiometer has a maximum value of 100k ohms and is located about 1 meter from the Arduino. The potentiometer's wiper is wired to the ...
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0answers
44 views
How does the size of a conductor affect a driven voltage?
I'm designing a capacitive sensor which uses an active shield to focus the sensing field. This much works well.
Now, in order to most effectively protect the active signal from noise I'd like the ...
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1answer
109 views
SD card connector chassis grounding
I have been designing a PCB which includes an SD card connector. As I'm not a PCB designer expert, I was looking for a reference design when I came across with the circuit bellow, extracted from Texas ...
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2answers
78 views
What does metal to metal bottoming mean?
Some connectors datasheets specify the following:
Metal-to-metal bottoming for maximum EMI shielding under extreme vibration
Reference: Dualok Connectors
I have also encountered the following for ...
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2answers
123 views
Does burying a cable shield it?
TL;DR: Does burying a cable provide shielding? I.e., is a shielded cable in air equivalent to an unshielded cable buried ~ 6 inches in soil?
Long:
I'm a technician at a university. I don't have ...
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1answer
151 views
Shielded cable, to ground or not, in amplifier
I have been looking for an answer on the net about this question but not found it fully answered. The topic has been up here a few times (see links below) as well but I find the answers lacking.
My ...
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1answer
54 views
How to shield a battery powered instrumentation with USB interface?
I would like to ask for advice on shielding the following setup.
I have a measurement target sitting inside a Faraday cage, connected through a shielded cable to a measurement circuit. The cable ...
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1answer
43 views
dip switch electric shield
I have ordered a Reed Relay with a diode and electric shield, but I am not sure how to connect the shield to the rest of the circuit because I do not know what the shield does and how does it work in ...
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3answers
66 views
Is there any sense in carrying assembled enclosed electronics in a static-shielding bag?
Say I have a Raspberry Pi enclosed in a metal case, such as this:
Would it offer any additional level protection if I put it in a static-shielding antistatic bag whenever I carry it around (e.g. ...
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2answers
68 views
How should I use a static-shielding bag prior to opening, and why?
After grounding the ESD mat and wearing the properly grounded anti-static wrist strap, what is the correct process to take the contents out of the static-shielding bag and take it onto the antistatic ...
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62 views
Can a grounded static-shielding antistatic bag be used as a circuitry work surface to protect from ESD?
Basically, I have looked around about how to take proper care with respect to ESD and I am quite confused. I know an antistatic bag of any type would not provide additional protection from ESD if used ...
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1answer
40 views
A question about AC Ground and Shielding
I see this question on EE but reading those I am not sure they answer what I am asking here.
This is the problem. I am designing an audio device that is powered by an external 15VDC adapter. This ...
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5answers
238 views
Electromagnetic shielding and EMP
I've asked several related questions, but I'm afraid that some of the answers that I received, while great answers, might be skewed because of incorrect assumptions or unclarity in my questions.
The ...
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2answers
73 views
Is it easier to attenuate a sine wave or a more complex wave?
All other variables being equal, how does waveform complexity of a plane wave affect shielding effectiveness? Is it easier to attenuate a sine wave or a complex waveform?
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0answers
79 views
Skin effect of copper in a high-strength AC magnetic field
I'm trying to determine the thickness of copper foil required to construct an enclosure that attenuates a very fast-rising, very brief pulse of AC magnetic field at a frequency of 1 MHz and field ...
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0answers
63 views
How to calculate attenuation of two layers of RFI shielding material
I'm developing a type of enclosure that provides EMR shielding. It's constructed of two layers of shielding material. I don't have access to professional test equipment, so my dynamic range is ...
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1answer
74 views
How to build EMF radiation protection [closed]
I've recently started to use my laptop more and more on my lap and I'm worried about exposire to radiation emmited by the laptop.
I keep it at a distance of about 10cm but still...
I was wondering if ...
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2answers
135 views
What are the limitations of “fake” balanced audio cables?
I have an AV receiver providing amplified outputs and preamp outputs.
The pre-amp outputs are in the form of (unbalanced) RCA jacks. My speakers are amplified and have a balanced input.
I was ...
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3answers
545 views
Why is a caseless PC not an EMI problem?
As I understand it, the case of a PC is metal so that it can form an EMI enclosure around the electronic parts. My view is reinforced by there being conductive fingerstrips around the mating edges.
...
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4answers
108 views
Blocking cell phone interference on LM386 amp
I built a small amplifier using an LM386 on a protoboard. The problem I have however is that it makes those typical cell phone sounds if my mobile phone is close to it.
Since I want to 3d print an ...
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2answers
471 views
DMX: What should I do with ground and shield?
I'm currently developing a DMX interface (master interface) with USB and Ethernet connections. The power for my device I'm retrieving from the 5V of the USB connector.
The shield of the USB connector ...
6
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2answers
777 views
How can I make a diy anechoic chamber?
I'd like to make a small anechoic box for RF measurements. I need roughly a 30x30x30cm cube of usable space, and I'd like the reflections from the walls to be attenuated by 10dB or more from 100MHz ...
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1answer
51 views
If I run electrical current through the conductors in a magnetic shield, can It be used to shield stronger magnetic fields?
I'm wondering if running electrical current through a shield amplifies its effect to a significant extent, effectively making it into a shield you can "turn on and off" for stronger magnetic fields ...
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1answer
36 views
Current Rating of Stepper Shield Ground Wire
I have a 2 phase bipolar stepper motor;
https://catalog.orientalmotor.com/item/all-categories/20mm-pkp-series-2-phase-bipolar-stepper-motors/pkp214d06a-2
Its 4 power wires are wrapped in a shielded ...
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3answers
131 views
EMI shielding without shield? [closed]
Hi I sorted of had an epiphany when thinking about EMI shielding a PCB...
If the frequency of the system on a PCB was constant ( lets 20MHz digital system or something) could I take advantage of that ...
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2answers
407 views
Confusion in grounding shield wires of transducers
There is a 6-wire Wheatstone bridge type load-cell and one of the wire is called shield and it is electrically connected to the metallic case of the load cell as below(I marked that with yellow ...
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0answers
71 views
How to check if the isolation room is causing noise in MRI images
The schematic shows how an MRI shielding is supposed to be done. You have (1) the physical room where everything is installed, (2) isolating materials to isolate the main room from the MRI room, and (...
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1answer
75 views
Which one of these shielded scenarios is correct?
I have a system were both the signal generated and the sensing equipment is sharing the same ground.
Which one of these shield terminations scenarios is correct? (if any). I searched the internet for ...
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1answer
63 views
How should I connect a braided shield 2-core cable with a headphone plug with three cores
I'm a beginner in Electronics.
The cable has two cores and a braided shield. What should I do about the ground?
2
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1answer
52 views
Unshielded RJ45 connectors on SFTP Cat5e
I have "inherited" an old SFTP Cat5e cable connecting the basement of my house to the upper floor. There seems to be a break on some of the wires (6 and 7) so it won't even function at 100mbps.
I ...
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1answer
295 views
ungrounded chassis shielding
I'm looking into whether an ungrounded metal box provides good/bad EM shielding.
This thread seems like a definite "good", for reasons of the box acting as a faraday cage : How much shielding does an ...
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1answer
329 views
Shielded breadboard jumper cable wires
Does it exist a shielded version of 2.54mm pitch breadboard jumper cable wires?
Thin flexible wires, Gauge AWG 24-28. I want use shielded wires for JTAG cable, to reduce electrical noise from ...
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2answers
225 views
How to determine quality of headphone earbuds by spec sheet?
I have been doing some work with cheap headphone earbuds for quite a while now. I was wondering, when buying earbuds in bulk, if there was any way to tell what the sound quality would be before ...
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1answer
246 views
USB OTG Cable Shielding
I just soldered a USB OTG cable to connect a keyboard (regular USB-A) to a Raspberry Pi Zero (micro-USB).
How to wire the VCC, GND, D- and D+ pins was obvious and the cable works. However both ...
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1answer
144 views
Cable shielding groundloop
I am trying to connect a encoder to a motor controller which runs very close to the motor that it controls (30+ amps). Due to the risk of high EMI of the motor inducing on the encoder signals, we send ...
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3answers
519 views
Why does my GPS and Wi-Fi work inside a sealed copper clad box?
I have just finished assembling a Raspberry Pi-based project into a DIY box made from copper clad FR4 PCB, with the edges soldered together and the copper surface connected to ground.
I expected, ...
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1answer
118 views
Should it be expected that some shielded wire is not good at data transmission?
I have recently purchased a reel of this specification screened wire from RS Components to use in I2C communications, expecting it to be very well suited to purpose. I am running at approximately 400 ...
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0answers
136 views
How do I choose a twisted pair shielded cable?
The charging/discharging of a battery (1u to 30 mA) and remote voltage measurement is to be performed over 2 pairs of 2 m cable. In order to reduce picked up common mode noise I intend to use shielded ...
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1answer
299 views
Encapsulating an inductor with epoxy and ferrite powder
Say I have some SMD inductors and I'm trying to limit their EMF from the rest of the board, can I simply potty it with epoxy mixed with ferrite powder (or perhaps iron filings), if I make sure the ...
2
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3answers
344 views
Connect signal ground to safety ground?
We are designing a product which has to meet EMC directives. It consists of metal backplate folded into a chasis (the front is open). on the backcover there is a SMPS mounted. and on top of this we ...
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2answers
872 views
Should I connect a cable's shield to the ground layer of board when it's isolated from earth?
I have a controller board powered by DC that may or may not be isolated from earth ground. The chassis of the device is non-metallic.
This board connects through a long (30-40m), shielded cable to a ...
2
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1answer
48 views
Calculate field strength for shielded isotropic transmitter
How to calculate the field strength of a shielded theoretical isotropic transmitter, if there is a hole in the shield for example.
I am looking for a complex formula that also takes into account the ...
0
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3answers
93 views
Is the “antenna aperture” the same as the “hole in the shield”?
Is the concept of the "Antenna Aperture" the same as a hole in a electromagnetic shield? The wikipedia article is quite vague, and I am a newbie in this field.
For example if we have an electric ...
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2answers
705 views
Purpose of bare copper perimiters on HF PCBs
I have seen many RF PCBs with a thick, rounded area of exposed copper going all around the PCB, like in this example:
My intuitive thought is that this is for some kind of grounding or shielding can, ...
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4answers
186 views
Can an alternating magnetic field be “informationally” shielded?
I have asked previously about the properties & shielding of the "static" magnetic field previously, where I have determined that static fields are hard to shield.
However what I am really ...
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4answers
184 views
Can a “static” magnetic field carry Information? [closed]
Information is electronically represented as some energy that is changing, therefore we measure an on state (1) and an off state (0), to create a (0,1) binary representation of the information.
Now a ...
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3answers
1k views
Does Shielding “Electrically” shield “Magnetically” too?
I know it sounds like a newbie question but I can't wrap my mind around it. An electromagnetic field is electric + magnetic field.
So this means that when shielding an equipment offensively, for ...
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3answers
52 views
Is better to have holes on different sides of the shield instead of the same side?
I suppose the best is to have no hole on the shield, but that is practially impossible if you have to let cables come out of it.
So I read somewhere that having the holes on different sides of the ...
