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Questions tagged [shielding]

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

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EMC pre-compliance grounding issue

During pre-compliance EMC tests in an accredited testing house, I have faced a weird issue which convinced me to isolate the system ground from chassis ground. The system is a DC-powered INS with ...
M.A.T's user avatar
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1 vote
3 answers
135 views

Shield termination techniques on military-style connectors

References such as PT06A-10-6S (see image bellow) are military-style connectors. I would like to connect my cable's foil and braid shielding to the chassis ground of my connector pannel via the PT06A ...
Tommy95's user avatar
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1 answer
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Cable type selection for 128 channel signal transfer [closed]

I want to use a cable to be connected (soldered) to my PCB, my PCB has 128 pads on it as follows: The signal that will be transfer to cable is @3 MHz to 6 MHZ, in range of 150 uA. The width of the ...
Andromeda's user avatar
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0 answers
38 views

Battery powered IoT lightning sensor shielding

I have a low-power wireless solar powered IoT sensor that has a Geiger counter (400V SBM20 tube) on board and is controlled by ATmega328P, sitting outside. This set-up has been working great for ...
bobnecat's user avatar
2 votes
1 answer
57 views

How can I shield electronic devices against interference from a plasma cutter? [closed]

I am trying to build an NC plasma cutter with a 3D printer. This was the setup: To do some tests I've mounted the plasma torch (Parkside) to the printer's (Creality CR-10) carriage. The button on the ...
big_bear's user avatar
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4 answers
89 views

Should I use a metallic enclosure for my low-noise circuit?

I am trying to design an ultra-low-noise pre-amplification stage for a MEMS. The amplification consists of a non-inverting amplifier specifically chosen to have less than 4 nV/sqrt(Hz) as input ...
jrad's user avatar
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2 votes
0 answers
23 views

Better to terminate guard ring to cable shield or leave shield unconnected at load?

I am working on designing a precision rectifier and charge amplifier for a small-signal piezo transducer. This tiny board will be a sensor "load" sending a mV-to-1V amplified analog signal ...
Matt001's user avatar
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2 votes
1 answer
67 views

Cable shield connection to metal enclosure on rolling stock

It's standard practice to ground cable shields at both ends to prevent EMC issues. I am uncertain if this practice applies to enclosures installed on train roofs. In my setup, I have an I/O cable ...
M.A.T's user avatar
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1 vote
1 answer
37 views

Board-To-Board Connector : Shield Pins : Voltage Bus?

Question On a board-to-board connector, can the shield pins be used as power pins to carry bus voltage, or should shield pins always be tied to return? Specific Connector In my specific case, the ...
kando's user avatar
  • 437
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39 views

How can I insulate cables using a copper braid too thin to sheathe them?

I have high-voltage SHV cables that I need to shield using a copper braid. I am using sensitive electronics and these cables appear to be a source of noise. The only copper braid that I have available,...
C. Crt's user avatar
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7 votes
2 answers
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Is using the shield in a CAT cable for return current a bad idea?

Consider a PoE solution that uses shielded CAT cables and where the shield is connected to signal ground on both the PSE and the PD side. In this case, the shield is most probably presenting a lower ...
FreddaH's user avatar
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How do the currents induced by the E-field and H- field flow? Which of the two currents induced by E or H has the larger amplitude?

I came across this problem for an exam preparation question, which I am struggling to answer. Consider a sphere made of thin metal, with a radius of 1 m, at 20 km distance from an AM transmitter ...
HAPU's user avatar
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2 votes
1 answer
182 views

Where to connect shielded cable when you have no chassis?

I joined a project after some of the initial design decisions were made, so it’s not quite how I’d like it, which now presents me with a bit of a problem. I have two power cables that are emitting ...
Sylvester's user avatar
1 vote
0 answers
39 views

Proper bending of trace in high frequency coupler question

A coupler 32-38 GHz was designed. I need to bend the legs in an optimal way so I won't get reflections. My bend is 45 degrees. Is there a logic I could use to find the optimal distance of the bended ...
Josh23's user avatar
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1 vote
1 answer
91 views

EMC: PWM signal: Signal return vs ungrounded return

When there will be many (48) long (200 mm) overlapping PWM-signal traces driving separate LEDs, which merge together in a pad post-LEDs to then share a long (200 mm) trace back to a MOSFET switch ...
kando's user avatar
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3 answers
130 views

Can I use a USB C connector?

In my system, one of my modules operates at 36V, 500mA. I use Harwin power connector M80-8980405 (cable side), M80-8820442 (PCB side) to interface. These connectors are not shielded. I am looking for ...
NICEGUY NICEGUY's user avatar
1 vote
1 answer
158 views

Ethernet circular hybrid connector grounding and shielding

I have developed a board based on STM32F207ZG MCU with Ethernet interface using: LAN8742A TVS diodes device for differential pair signaling Magnetic-transformer device Hybrid circular connector from ...
Suvi_Eu's user avatar
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0 answers
81 views

How to connect cable shield when receiver side powers signal source?

I have element 'A', the receiver, connected to earth, which powers modules 'B' and 'C', the signal sources, unconnected to earth. 'B' sends a differential line signal, and 'C' sends an analog signal. ...
Tommy95's user avatar
  • 179
12 votes
4 answers
4k views

Cable shielding (best practices)

I am making a cable to connect two boards as shown in the image below: The cable will be around 25 cm long and will be in an electrically noisy environment (consider 220 VAC house wiring lines ...
Whiskeyjack's user avatar
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How to shield a wireless microphone receiver from hdmi cables running under it?

We have some wireless microphones set up with the receivers in a confined space. After adding some HDMI cables (for streaming purposes) we now have an interference problem. While the transmitter is ...
Louis Somers's user avatar
0 votes
1 answer
265 views

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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1 vote
1 answer
74 views

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
1 vote
1 answer
229 views

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
  • 11
2 votes
2 answers
362 views

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.) ...
HansPeterLoft's user avatar
1 vote
2 answers
48 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 ...
davegravy's user avatar
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0 answers
22 views

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.
Rishab's user avatar
  • 31
2 votes
0 answers
109 views

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
201 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
  • 31
2 votes
2 answers
941 views

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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7 votes
2 answers
2k views

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
  • 439
0 votes
1 answer
85 views

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 ...
shklj's user avatar
  • 27
0 votes
1 answer
49 views

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
420 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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1 vote
1 answer
253 views

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
  • 2,131
4 votes
4 answers
1k views

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?...
JoeyB's user avatar
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1 vote
0 answers
35 views

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
0 votes
2 answers
285 views

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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0 votes
0 answers
35 views

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
  • 83
0 votes
1 answer
189 views

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 ...
Geo's user avatar
  • 754
0 votes
1 answer
273 views

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
1 vote
0 answers
202 views

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
0 votes
1 answer
50 views

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
  • 133
0 votes
2 answers
447 views

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
  • 163
0 votes
0 answers
59 views

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
  • 181
1 vote
2 answers
96 views

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
  • 123
0 votes
1 answer
871 views

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
  • 123
26 votes
3 answers
4k 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
  • 1,344
3 votes
1 answer
221 views

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
  • 1,130
1 vote
1 answer
127 views

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

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