Questions tagged [shielding]
Questions regarding shielding devices against noise, interference, or ESD. Not to be confused with arduino-shield.
244
questions
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3answers
56 views
Extra pin for shielding with CAN bus connector
I am presently using a 4 wire bus for CAN (CANH,CANL,PWR,GND). This is used all across the design for various boards. Now the cable needs to be shielded.
Would this imply using 5 pin connectors and ...
0
votes
1answer
51 views
What's are the material properties that distinguish a magnetic containment disk from an induction cooker?
My picture below shows a coil carrying AC current, generating an alternating magnetic field. On top of the coil I've drawn a disk of high-permeability metal. Such as carbon steel, or mu-metal.
If the ...
3
votes
1answer
85 views
What is the plastic barrier surrounding this choke for?
I disassembled the mains power supply from an audio mixing desk. Immediately after the switch and inrush protection NTC is an Epcos B82722 10mH / 1A choke (the blue component in the photo below).
The ...
15
votes
5answers
2k views
Cable shielding adequate for video, but not audio frequencies
I am no expert in audio equipment, but to educate myself I have been studying. In the process, I came across a video which tests the audio frequency shielding of a purported shielded video cable. (I ...
1
vote
1answer
55 views
Why do (magnetic) absorber sheets work?
I understand how/why graded absorbers work - you achieve a match with free space by gradually varying the electromagnetic properties from "almost air" to strong absorption (either ...
0
votes
2answers
94 views
Holes in RF shield, what frequencies can escape?
So this is part of a theoretical design problem that I've come across not too long ago, and still can't find a satisfactory answer for it.
Assume a large (infinite) metal plane with a round hole in it ...
0
votes
0answers
30 views
Raspberry Pi : White/Blank screen with new shielded cable
I'm currently passing EMC tests at a test lab. For the purpose of the tests, I made a custom DSI cable for the official Raspberry Pi 7" screen with shield against EMI as the PCB of the official ...
1
vote
0answers
51 views
Cable Issues with USB HS
We’re working on a product that makes use of USB HS, and are having some connection and consistency issues.
Originally, our product was USB FS-based and we had no connectivity issues; with this second ...
1
vote
0answers
47 views
What metal(s) are old game console RF shields made of and coated with?
I'm restoring my old game consoles (like NES) and am having trouble finding what the RF shields are made out of and coated with so I can sand out the corrosion and re-plate them.
I thought it might be ...
1
vote
0answers
39 views
Wireless charging with metal plate on back of phone: eddy currents wasting energy and heating up?
I just got a car mount for my phone which uses a small magnet stuck to the back of my phone. I'm not sure the material, but I'm guessing it's conductive.
My concern is with wirelessly charging my ...
0
votes
0answers
39 views
Basic shielding practice for simple passive audio project in an enclosure?
I'm a tinkerer but not an electrical engineer. I'm constructing a stereo->mono summing box for my stereo (to listen to Beatles LPs properly, natch). I'm using the design & schematic here for ...
0
votes
1answer
45 views
Connecting USB shielding of two hosts and one peripheral
I'm making a simple project regarding switching USB connection between two computers. I would like to know if it is safe to connect USB shielding for pc1, pc2 and peripheral together, while keeping ...
8
votes
4answers
612 views
Active guard shielding for instrumentation amplifier
I want to use the the AD8221 amplifier as a conditioner for my load cell. I saw that to reduce noise I can use an "active guard shield driver" between the "REF" of my amplifier and ...
0
votes
1answer
51 views
Avoiding ground loop through d-sub like connector shield over metal enclosure
I have to pass a couple of analog signals between separately grounded systems over a HPDB68 cable. Ground loops have been a major issue previously, so the signals are passed differentially and ...
0
votes
2answers
90 views
RFID antenna beam direction and how to control it
I've been working on some RFID stuff lately and I'm wondering if someone could help me understand how the beam direction works?
I'm having problems with my RFID reader picking up signals from tags ...
0
votes
1answer
41 views
How to connect interfaces' shields?
I am designing a new PCB board these days, and I am confused about how to connect interfaces' shields. The interfaces on the board include USB, RJ45 and D-SUB, should them be connected directly to ...
0
votes
2answers
38 views
In wifi modules what does the shield have to protect?
All wifi modules have a shield over the chip but what I’m wondering is if the track to the antenna need to be shielded or is it just the chip that needs shielding ? Thanks Ben
0
votes
0answers
32 views
Should via-stitched polygons connect to adjacent analog grounds?
I am putting together an analog PCB. I am reading an audio signal and using large gain to clip it (effectively a crude digital signal 0-5V) using a differential amplifier. It is a 2-layer PCB with the ...
1
vote
1answer
266 views
Is an aluminum foil wrap working as a shield in my spliced USB cable?
I'm preparing to cut apart a non-trivial $ device and try to extend a 4-conductor cable, so I have been practicing my splicing skills. I figured a USB cable would be a good test.
I spliced, heat-...
0
votes
1answer
225 views
How to shield your microphone the best way
I hope this is not a too simple question for this forum.
I have an issue with EMI/RMI on a microphone I am building. It's picking up noice from wifi hubs, computer screens and mains. I do not want to ...
0
votes
0answers
28 views
Wiring Stepper Motor / Placement of Stepper Motor Driver
I'm making a CNC-like machine and I'm in the process of designing PCBs for the head assembly. Currently I have stepper motor driver (with 100uF caps on the power line) on the head assembly and I'm ...
0
votes
0answers
100 views
Where to properly terminate 4-20mA cable shield in ungrounded low voltage DC system?
Preface:
I read both: ungrounded chassis shielding
and: RS485: Where to connect the cable shield in a battery-powered system?
A sensor system I'm working on is getting installed in a 20x20' cement ...
5
votes
7answers
319 views
Frame grounding, data & power - EMI
I'm looking into building some large robotics with (ofcourse) a frame, (shielded) data/communication cables - EtherCAT, and power lines.
Now different 'experts', websites and people say all different ...
1
vote
1answer
134 views
Does alumide provide any electromagnetic shielding?
Alumide is a new 3D printing material that contains aluminium dust. It is mechanically stiffer, but little is said about its conductivity and electromagnetic shielding properties. There is probably ...
2
votes
1answer
359 views
Basics of board level shielding and grounding
I have been designing MCU based PCB that must be withstand hard EMI tests. This PCB includes ethernet transceivers, can transceivers, rs485 transceivers, II2 chips, 25MHZ oscillators, optoisolators ...
0
votes
1answer
116 views
Ethernet connectors shielding/ grounding
I am currently trying to derive the relevance of ethernet connections shielding and grounding. This is regarding the robustness of the design (in terms of communication) and eventual ESD ...
0
votes
1answer
52 views
How good is the idea to place mostly entire copper layer up and down the functional layers in PCB?
My PCB contains PWM - driven LEDs. The specs says the internal oscillator runs at about 5.6 MHz, with currents of 30 mA per line and there are 56 lines in total. As the indicators are very large (10 ...
0
votes
0answers
33 views
Adding Ground or Earth to the shielded cable
I am using 8 core shielded cable to transfer I2C signal along with analog sensor data. We have connected earth to the shied cable, we have option to connect DC ground also. Everywhere I have read ...
0
votes
0answers
65 views
Should I (and in what degree) be concerned about EMI/RFI shielding?
I am starting on designing a sort of HAT (like used on the RPi) for the Nvidia Jetson Nano. As I am on my third year of electrical engineering I know little to nothing about EMI and shielding. Should ...
1
vote
1answer
42 views
Shielding a signal with both GND and supply? [closed]
What happens if a net is shielded by GND on one side and VCC on the other side inside an IC? Assume that the 3 lines are on the same metal layer.
This is an interview question and I would like to know ...
1
vote
1answer
77 views
Which parts of this U.FL laptop wifi antenna need to be exposed?
I got these wifi antennas for use in a small metal computer case. I'm cutting some holes in the case to give the antennas exposure, but I'm not sure what parts of the antenna need to be exposed. As ...
0
votes
1answer
61 views
Which side is the shield's drain cable connected and why?
I have 2 PCBAs connected using a shielded cable. The cable is transmitting an SPI signal from master PCBA to the slave at 30MHz. I have previously been advised to shield on the driving circuit (master....
1
vote
0answers
36 views
Advice on Bulk Current Injection Testing
I am having trouble getting a new product I'm working on to pass Bulk Current Injection Testing. I had trouble on the 50mA test at around 30MHz where the Ethernet link was not functional.
I have a 6 ...
4
votes
2answers
160 views
Amp circruit from PC speakers, why the connection to cable shielding?
I've taken apart some Logitech PC speakers in order to use the amp inside an bartop Raspberry Pi arcade game I'm making. There's something I don't understand. The donor speakers work as follows: R ...
2
votes
2answers
701 views
CAN Bus on PCB traces instead of twisted pair cable - points to consider
In order to save cost on the system in one of my current projects (no cables) I would like to eliminate the CAN cable and add traces to the PCB (one pair from left to right to connect the connectors + ...
0
votes
0answers
60 views
Will a vacuum tank shield against microwaves?
I am working on an experiment that involves 50-250W of microwave radiation. The antenna will be inside a small vacuum chamber (~2ft Dia x 3ft long) with ~1.5" steel walls. There are a handful ...
1
vote
1answer
72 views
Would there be a significant difference if a metal shield is connected or not to the circuit ground?
Assuming that we have a sensitive electronics that is battery powered, which consist of a very sensitive 32 bit adc is reading a voltage from a chemical reaction and you place it inside a chunky 1 ...
0
votes
1answer
59 views
I/O panel filtering for shielded room
We are looking into setting up a very basic shielded chamber inside a small room at my company to be able to perform some basic relative radiated EMC measurements.
We will buy a somewhat cheap ...
4
votes
4answers
2k views
75 Ohm Coaxial Cable Used On a 600 Ohm Output
I'm working on restoring an HP 211A square-wave generator and I'm looking to add a shielded cable to the 600 ohm output. I've got some spare 75 ohm RG59 cabling and I was wanting to know if using that ...
0
votes
1answer
103 views
How does the shield of a coaxial cable work?
let's consider a coaxial cable with only two conductors (the core and the external metallic shield), and let's consider the case in which it propagates TEM mode at a certain frequency:
My question is:...
1
vote
1answer
186 views
Electromagnetically shield guitar pedal
I've built a few guitar pedals using op-amps, transistors, etc. (with supporting resistors & capacitors of course), and I've generally 3D printed the housing for the components for custom designs. ...
-4
votes
1answer
87 views
What degree of magnetic shielding does a Kozyrev Mirror require? [closed]
After learning about kozyrev mirrors, I’m curious what types of fields they’re designed to shield. “The earth’s electromagnetic field” was all I could find. But does that mean just earths magnetic ...
1
vote
1answer
54 views
Self solder 8-pin din cable
a bit of specific question. I want to build my own cable based on pins stated in the manual of an old camera, so I can capture the video (composite video) and audio signal.
Question: Is there ...
0
votes
1answer
198 views
What is the “leakage current” between signal and shield?
Consider a coaxial cable with shield not connected to anything. My textbook seems to suggest that there will be leakage current between the "signal" and the "shield".
I have two questions:
1) ...
1
vote
1answer
548 views
Shielded Ethernet Cables in Office Buildings - Ground Loops?
I have a question related to shielding and grounding of ethernet cabling in industrial environments, offices and datacentres.
What I assumed as correct so far (please correct me if I’m wrong):
In ...
1
vote
0answers
45 views
Prevent Reception from an Extended Distance (Beyond Design)
I have a magnetic field that is being induced onto a power line by a transmitter, which is following the length of the power line to the receiver. The receiver communicates via a loosely coupled coil ...
2
votes
5answers
293 views
Considerations for transmitting the signal from a MEMS microphone over a short cable?
In my application I have the signals from 6 analog MEMS microphones (CUI Devices CMM-3729AT-42108-TR), each amplified by a pair of op-amps in a voltage follower -> inverting amp configuration. The ...
0
votes
0answers
51 views
Can current absorbed by a shield of a cable be harmful to a human?
I wonder if I should isolate shielding everywhere throughout the system. It is a bit costly because shields are on the outside and tend to touch a bunch of outer metal parts. But then humans can touch ...
1
vote
1answer
84 views
Decoupling capacitors on opposite side of board when using PCB mount EMI shield
When using a PCB mount EMI shield, can you put decoupling capacitors on the back side of the board?
Well of course you can put them there, but will it make the shield essentially useless? Or will ...
2
votes
1answer
61 views
How do I shield PLB signals?
I am trying to refurbish an electronic personal locator beacon (for rescue callouts for stranded hikers/sailors/pilots).
To do so to spec most devices require a GPS signal test (activation). There is ...
