Questions tagged [shielding]

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

41 questions with no upvoted or accepted answers
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103 views

RFI protection for a stepper motor controller

I'm building a remote tuning device for a magnetic loop antenna. It will use a stepper motor to turn the shaft on the mag loop's variable capacitor. The electronics will consist primarily of a ...
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52 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 ...
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95 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
2k views

Understand the shielding of a USB device

I have a GPS PCB which has regular USB pinouts (GND, +5V, DATA- and DATA+), but in addition has one stranded wire which is connected to USB type A plug. Marked as "USB connector" on the image: What ...
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0answers
5k views

Shielding effectiveness calculation

From The Basic Principles of Shielding: Apertures, or holes, have SE. The SE of an aperture and ultimately the entire electronic enclosure is determined by the size, shape and number of the apertures....
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1answer
333 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 ...
2
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1answer
559 views

Advice for Grounding and Shield Placement

I am working on a board design which includes an ADC and a DAC. The board attaches to the headers of the Mojo V3 Spartan 6 FPGA Dev Board. The ADC has to pick up a quiet signal at the same time as the ...
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53 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 ...
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0answers
42 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 ...
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43 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 ...
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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 ...
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1answer
60 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 ...
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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 ...
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1answer
95 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 ...
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2answers
120 views

How can I reduce noise caused by shift register updates?

I have a couple of designs using 74HC595BQ-Q100,115 shift registers. Some are using the SO-16 package, some the DHVQFN16. Some have five shift registers, some have three. ALL have a significant ...
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0answers
312 views

Twisted pair with shield and drain wire

Ive been posed with a problem regarding calculating the characteristic impedance of a shielded twisted pair with a drain wire. While I understand how to calculate this for a "normal" shielded twisted ...
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0answers
202 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
60 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 ...
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0answers
182 views

Why compass module is affected by its x,y position, if my phone's compass work in the same environment?

I am using hmc5883L on an autonomus robot. It shall remain in a 1 meter squared area. I have recently discovered that its reading changes up to 20 degrees on different positions even when it is facing ...
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1answer
77 views

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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0answers
35 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 ...
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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 ...
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1answer
47 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 ...
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1answer
64 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 ...
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1answer
43 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 ...
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0answers
34 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 ...
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0answers
34 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 ...
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126 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 ...
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36 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 ...
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73 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 ...
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1answer
66 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....
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61 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 ...
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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 ...
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2answers
68 views

How to connect a few shields correctly?

There are several shields on my PCB: shield on CAN-bus, on RS485, on Ethernet, on ENCODER motor signals. How do I correctly connect all these shields? If I use the star topology, which filters should ...
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88 views

Connecting TVS diodes to a floating shield

I need a little help with shielding for ECG leads. The design I'm working on has 3 leads, about 60mm in length. We use shielded cable for each lead, which all come to a meeting point at the ...
0
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1answer
104 views

Grounding and shielding between isolated devices

I have a battery operated micro controller with a hall sensor, mounted on a motorbike. The hall sensor has a shielded cable to counteract spark plug induced EMI. By default, the entire setup is ...
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1answer
59 views

ADC wire is picking up noise from cellular antenna [EMC]

I have a 5 wire micro jst cable with a line for ADC readings from an IR sensor that is picking up interference from the cellular antenna of the microcontroller. Will I be able to reduce this noise if ...
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1answer
67 views

Testing the integrity of cable shielding for suitability

I am currently working with an ECG cable, is there a way for me to test the integrity of the shielding of the cable without using it directly on an ECG monitor to check for interference.
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239 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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3answers
59 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 ...
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135 views

Shielding from inductive charging in simple PCB

I am going to design a fairly simple binary LED wrist watch. For a cool feature and a good learning experience I want it to have wireless charging capabilities so I purchased this wireless charging ...