Questions tagged [shielding]

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

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How to calculate the via fence spacing between two differential CPWG?

I designed a very compact 4 layer PCB that has many PCIe 2.0 differential pairs spaced in close proximity. In addition to the internal ground planes, I want to fill the signal layers with copper, and ...
AnB's user avatar
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Is there any practical purpose of placing read only memory (ROM) chip near a hard drive?

Premise: a PCB file has ROM chips (I think they are masked ROMs?) placed beside standard 3.5" HDDs, which has lead me to a few questions. While the product is off, I understand that the magnets ...
CodingFryCook's user avatar
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Calculate RF shielding property of aluminum sheet

I want to quantify the radio-frequency shielding properties of a sheet of aluminum. I have an RFID antenna shooting at 865 MHz and I want to shield the antenna so that I don't pick up tags behind the ...
nndei's user avatar
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Proper shielding of a specific circuit

I have a PCB, that will now be put into a conductive enclosure (connected to PE). The PCB has some power electronics (DC/DC converters, motor controller etc.), some communication interfaces (CAN etc.) ...
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2 answers
36 views

infrequent USB dropouts on SBC

I have a full speed USB audio device connected to the USB port on a SBC running Ubuntu Linux. I'm acquiring data over this connection and I need 24/7 uninterrupted data acquisition. If the USB ...
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RF shield mesh rules of thumb

When you place a RF transmitter within a metal enclosure with openings that can be approximated as a mesh, are there any rules of thumb for either letting the signal pass through or get attenuated? ...
NoobPointerException's user avatar
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Cable / Device Shielding

Is it required to connect Shield cover to the enclosure at several points in a defined way? I am doing EMC simualtion related to this and not sure on what changes I can make.
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EtherCAT - Correct Shielding of Slaves

According to Beckhoff, the EtherCAT Standard needs correct shielding to work reliable, since EtherCAT cannot tollerate a lot of jitter: Beckhoff Shielding Correct shielding means, that the shield is ...
HansPeterLoft's user avatar
3 votes
2 answers
152 views

Density of braid shielding

Does the shielding braid density depend on frequency range to provide good cable shielding? I have read that braiding works well for low frequency but that at high frequency the effectiveness ...
Rishab's user avatar
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Utility of shielding a laptop SSD with conductive foil -?

I recently replaced the factory SSD in my Thinkpad X260. The factory SSD came with one side covered in conductive aluminum foil which is grounded to the chassis via the caddy-screw attachment. The ...
Russ Bain's user avatar
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USB shielding, device or host side?

I have an SBC with a USB host port, but it is exposed as male header pins rather than a female USB port. I have soldered female headers to a USB cable and have a working but intermittant connection, ...
davegravy's user avatar
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Question on the USB connector shileding

I have a USB microphone, based on cm6533 chip, that appears to be in working condition, with the exception of it's fried USB type C connector. Upon closer inspection this is the circuit that houses ...
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Would grounded conductors placed on skin prevent signals from reaching a shielded body part?

Here is the scenario: You are in an environment where there are sources of EM signals that your body will pick up as though it were an antenna via capacitive coupling, i.e. what happens with the 50/...
Zacary Wengdom's user avatar
6 votes
1 answer
221 views

Ethernet cabling: UTP, STP, FTP, etc, when is shielding useful/needed?

When installing cabling for Ethernet purposes, the question often arises: does one want/need simple UTP or any of the shielded variants, i.e. F/UTP, S/UTP, SF/UTP, U/FTP, F/FTP, S/FTP or SF/FTP, often ...
jcaron's user avatar
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What's the intuition behind connecting a wire shield to the ground plane on a bare board?

I have an old (1970s) PCB that generates a (baseband, composite) NTSC video signal. It is a bare board without a containing chassis or case. I am using a shielded cable for the video output line and ...
BZo's user avatar
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Shielding and PCB ground

When should I connect the shield of my cable to the PCB ground plane and what effect will it have? In addition, what effect do those shieldings have on EMI, does the shielding block out HF or LF noise?...
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Why do I have higher noise at far end of a DC power cable even when unplugged at that end?

I have a 750W DCDC converter that is putting out 24v. The converter has a stated ripple max of around 600mV and when measured directly at the output (scope lead tip pin the the output, lead ground ...
Sylvester's user avatar
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Doubt about grounding loop and shielding

Good morning, first at all I want excuse me for my english and my inexperience. I have working with complex setup (osciloscope+SMU+Waveform generator+ some circuits and shielding cage) and now Im ...
Sourc3w's user avatar
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What happens when the attenuation between radios in an RF test bed becomes higher than the RF leakage attenuation of the coax cables?

If I have an RF testbed with radios connected to each other via an attenuation matrix, what happens when that attenuation between radios exceeds the rated attenuation of the braided shield coax cable (...
Macuser's user avatar
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Shielded header cables or alternatives for IDC / 2x8 header cables

For my project I currently use 2x8 IDC cables, all of them carrying digital data, like SPI, I2C and TDM (digital audio). As I have tested, I found that these cables bring in loads of noise to the ...
sandeepzgk's user avatar
17 votes
6 answers
3k views

Failed radiated emissions test on USB cable - USB module hardware and firmware improvements

I posted a few days about ago how our product failed ESD testing. Well, it also failed radiated emissions testing so I thought I'd make a separate post. The product is a 5V USB powered, non-radio, 3v3 ...
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How to connect the shield of a cable only on one side, if I need to transfer GND from one end to the other?

I have one jack output: Left, Right, GND. I am using a shielded cable to transfer this signal to an amp. I've read about ground loop and that I should only wire the shield of the cable on one of the ...
Cătălina Sîrbu's user avatar
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Shielding issues with RJ45 connectors

I've been dealing with a pretty nasty radiated emissions problem at work and I've pretty well exhausted any list of potential solutions/mitigation tactics to resolve this given the design constraints. ...
carbonboy25's user avatar
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Shielding that retains some attenuation as \$\omega \rightarrow 0\$?

I'm new to the world of shielding. It seems that with regular, "Faraday type", shielding you're at the mercy of the skin effect equation: Which blows up as \$\omega \rightarrow 0\$ Are ...
Eriek's user avatar
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2 answers
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Thermocouple readings affected by PE

I designed a controller for an electric pizza oven. The PCB has an MP-LDE03-20B0 power supply module on it. Everything works great except for measuring the temperature in the oven. I use thermocouples ...
Marek's user avatar
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RF noise filtering chassis or power return?

I need to place some filtering on the IO lines of a DC powered device. The RF noise is induced or conducted into the chassis of the equipment and also into the interconnecting cables. The frequencies ...
tarmogr's user avatar
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2 answers
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Does EMI shielding deteriorate with time?

Does EMI shielding sheets gain resistance/impedance with time? I am using a ~2 year old RF EMI Absorb sheet that my roommate found and gave to me because my electronics keep interfering with his radio....
max's user avatar
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Can I use a big piece of ungrounded metal as ground?

There is nowhere to ground; I don't have access to a copper rod that goes into the earth or to circuitry. In this room there are only wall outlets and a Czech hedgehog that is no longer used. It's not ...
max's user avatar
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25 votes
3 answers
3k views

Is twisting a single ended signal with its own GND really useful?

I know that the most robust way of transferring an analog signal over long distances is via differential pairs which are twisted together and then shielded (shield grounded at one end only). But ...
user42875's user avatar
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2 votes
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Do I need via shielding for the GPS antenna trace?

I'm working on a 4 layer board (signal, GND, PWR, signal). I have a NEO-M8P GPS module and the Hardware integration manual says to connect the antenna with a 50 ohms impedance trace to the connector ...
Rodo's user avatar
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1 answer
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Puzzling mains-frequency interference at output of signal generator

The output from the 1940's-era modulated oscillator I'm restoring is being fouled by a 50Hz signal and I haven't been able to find the cause of it - so I'm far from being able to eliminate it. It's a ...
Simon Owen's user avatar
2 votes
1 answer
132 views

What is going on regarding power toroid shielding? (some shielded, some unshielded, no apparent difference)

In this Digikey search for 47uH toroid inductors, the shielding column shows that some are considered shielded, and others are considered unshielded. And even from the same manufacturer (Bourns). A ...
MicroservicesOnDDD's user avatar
0 votes
1 answer
86 views

CNC Servo System Grounding

Here it's a sketch of a simplified CNC servo system. The servo drives are non isolated (Digital GND connected to Power GND, drawn as GND) (My main question on the picture too) #1: Why some ...
Buruhazard's user avatar
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2 answers
80 views

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 ...
timeskull's user avatar
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4 votes
2 answers
120 views

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 ...
NoobPointerException's user avatar
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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 ...
A A's user avatar
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0 answers
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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, ...
HansPeterLoft's user avatar
4 votes
1 answer
486 views

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 ...
hontou_'s user avatar
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0 votes
3 answers
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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 ...
Joshua S.'s user avatar
-2 votes
1 answer
248 views

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 ...
calvinglob's user avatar
7 votes
3 answers
2k 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 ...
Guy Bartkus's user avatar
1 vote
0 answers
35 views

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....
Hari's user avatar
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0 votes
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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 ...
Aniket Kumar's user avatar
2 votes
1 answer
81 views

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 ...
jfowkes's user avatar
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0 votes
4 answers
607 views

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 ...
tobalt's user avatar
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1 vote
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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?
JoeyB's user avatar
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0 votes
1 answer
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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 ...
Varonne's user avatar
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1 vote
1 answer
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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"...
tarmogr's user avatar
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1 vote
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 ...
Ben Booth's user avatar
2 votes
1 answer
374 views

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 ...
Mantabit's user avatar
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