Questions tagged [shielding]

Questions regarding shielding devices against noise, interference, or ESD. Not to be confused with arduino-shield.

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CAT6a Shielded Home Network Installation and Shielding

I am about to run the cables for my new home network. I've chosen to use CATa Shielded Cable with a rack mount setup as follows. The questions I have regard the shielding. Thank you in advance. The ...
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LCD scrambled by interference from RF plasma

My lab uses a custom-built setup to generate reactive plasma; basically metal plates in a vacuum desiccator energized by a BD-10A. I've built an arduino-based control box for it to allow more precise ...
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When to employ RF shield cover on PCBA?

During reparations and teardowns I have frequently come across PCB-mounted RF shields and covers. While I don't typically work with GHz processors or design RF modules I wonder if such covers could be ...
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When the electric field EMF radiation hits tin foil why does it result in a magnetic field?

I have a cheap Erickhill EMF reader that measures “electric field” and “magnetic field”. I’ve been experiencing an odd phenomena that I can’t quite explain of a electrical sound emanating from a ...
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Correct shielding in different situations

For me shielding is always a difficult question. I'm sometimes really unsure how I should connect the shield. What I know is that the shield should be connected with very low impedance, that for sure, ...
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How does electromagnetic shielding work?

How does electromagnetic shielding work in cables? I learned from school that foils are used as shields in coaxial cables to "shield" them from external electric and magnetic fields. It also ...
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Tips on designing a shielded stepped linear resistance box

I need a shielded, linear, stepped resistance for an experimental setup. Requirements: 1000 Ohm to 1 MOhm Resistance accuracy is not of high concern: +-1000 Ohm is acceptable BNC in and out 50 kHz ...
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Do I need EMI shielding for a 5V signal PCB placed beside high powered DC cable 48V 50A?

I have PCBs located just below the high-powered DC cable at 50A 48V. My PCB has input-output from 5V signal cables from all over the place. The 5V signals are for: 12V and 5V Signal driving the EM ...
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Help with providing a ground to an external circuit without compromising shielding

As per my previous post, I am attempting to use a lock in amplifier to detect changes in impedance across a small wire gap (probe) boxed with a dotted line as shown in the drawing below. I would like ...
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5 votes
3 answers
775 views

Does a shielded inductor store less energy than an unshielded one?

As you can see in the image above, the magnetic field of the shielded inductor looks smaller, but does this mean the unshielded inductor can store more energy? (This all assuming the inductors are ...
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Optimizing Precision Photodiode Sensor Circuit Design-keep-out around the trace calculation

I am going through this document from Analog devices to learn more about different guarding methods.(https://www.analog.com/en/technical-articles/optimizing-precision-photodiode-sensor-circuit-design....
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Is it possible to shield a metal ball with electrostatic shielding, or any other way?

Is it possible to shield a metal ball by the electrostatic shielding such that metal ball doesn't suffer electrostatic induction? There is an electric field present near the metal ball but I want that ...
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2 votes
1 answer
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How should non-shielded connectors be handled in a casing design?

Assume a design with a mix of shielded connectors (e.g. USB, HDMI) and non-shielded connectors (e.g. standard 0.1" headers) A metallic casing is designed to mesh with the shielded connector ...
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How did using the shield as signal return end up as a common practice in audio?

Or in short: was cost the only motivation? Because the major reason against this practice must have been already plain obvious in the mid of last century. Namely, using the shield of a cable as signal ...
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USB C 2.0 Receptacle shield connection [duplicate]

I want to know if I should also connect the shield pin (Pin S1) in my schematic to GND or should I leave it not connected?
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Running and grounding paired shielded cable thru a connector

I need to run two logic signals around a vehicle, so for good measure, regardless if its overkill or not, I want to use a shielded single pair wire for that job. At one point it should be crimped to ...
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Common mode choke and grounding

How would you connect the cable shielding, metal enclosures and power ground on following system: Since I had problems with noise before I wanted to add filtering on power input for "my PCB"...
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1 answer
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How to protect the signal quality of LVDT input and output?

I am designing a 6 wire LVDT. I need to know how to protect the signal quality of both the primary excitation input and secondary coil outputs inside the LVDT, and inside the device in which the LVDT ...
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2 votes
1 answer
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Shielding AC magnetic field using cable shield connected to two grounds

I am currently reading a book about electromagnetic compatibility but I am confused about a section that talks about reducing the coupling between an external magnetic field \$ B_{ext}\$ and a circuit ...
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2 answers
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How bad will leaving a USB 2.0 cable's shielding disconnected be?

I have a keyboard with a fixed cable that I'm looking to reconfigure into a detachable one. It's a hefty cable that contains two separate USB 2.0 cables and some shielding. The shielding connects to ...
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Does a certain cable arrangement that reduces the generated magnetic field improve shielding properties as well?

If I arrange a three phase cable via phase-split into an arrangement that reduces the generated magentic field, does this affect shielding properties as well? To reduce the generated magnetic field of ...
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How can a cable tester verify correct shielding/twisting of wires?

Background: The company I work for makes a variety of special-purpose cable assemblies to go with equipment we make. The people who build these cables aren't doing a 100% reliable job, and nobody ...
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3 answers
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Better to Opto-Isolate on Sending or Receiving End? Isolating to Avoid EMI

I am working on an art project using some modified bug zapper circuitry to produce loud and bright sparks. I have the circuit working and the sparks are very impressive, but I'm running into a issue ...
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2 answers
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How to isolate leaky LO and antenna for FM radio?

I am building an FM receiver. My problem is that when powering my antenna circuit or LO circuit one at a time, I get the output of those circuits appearing very strongly on my power supply lines. When ...
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1 vote
1 answer
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Is metal casing always recommended/expected for audio devices (for EMI protection)?

I am considering using a wooden enclosure for several homemade audio devices such as DI boxes and isolation transformers but I know that most all commercial products use metal casing. I have noted, ...
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1 answer
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Need tips on creating a custom usb cable

In short, I have two questions: Does shielding matter for a USB2.0 cable inside a computer? The length is about 50 cm. Is the requirement that data wires should be thicker than data ones still valid ...
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Why should the "shell" of an XLR connector not be connected to pin 1?

I don't quite understand the grounding strategy of XLR connectors. The Wikipedia article on XLR 3-pin says the following: AES standards mentioned above recommend that shells of cable-mounted ...
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5 votes
2 answers
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Is removing noise with shield/capacitor making communication fail in this circuit?

We are puzzled by a surprise communication failure between our controller PCB and sensor PCB. Circuit Diagram for Sensor Communication Failure: The communication fails unless we do one or more of the ...
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Schematic notes: Place capacitor as "close" to pins: Is this a necessary note? Is it a significant point?

Background I am building a ATMega4809 board that allows the board to be programmed using the Arduino IDE. While examining the following schematic I noticed that where the caps are placed the author ...
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1 vote
2 answers
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Best shielding material for a Faraday cage against 36kHz electric fields?

I have a room aka cuboid with 4 x 3 x 2.5 meters. In the 3D center is a device under test. To shield against 36kHz electric fields I want to build a Faraday cage. I learned the hard way that aluminium ...
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2 answers
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Enhancing faraday cage

I have a room aka cuboid with 4 x 3 x 2.5meters. In the 3D center is a device under test. To shield against 36kHz electric fiels I have built a faraday cage by sticking 0,012mm thin and 30cm broad ...
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2 votes
3 answers
299 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 ...
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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 ...
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3 votes
1 answer
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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 ...
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15 votes
5 answers
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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 ...
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1 vote
1 answer
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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 ...
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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 ...
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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 ...
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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 ...
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2 votes
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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 ...
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1 vote
0 answers
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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 ...
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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 ...
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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 ...
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9 votes
4 answers
1k 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 ...
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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 ...
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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 ...
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1 answer
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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 ...
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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
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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 ...
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1 vote
1 answer
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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-...
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