Questions tagged [shielding]
Questions regarding shielding devices against noise, interference, or ESD. Not to be confused with arduino-shield.
199
questions
2
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5answers
252 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
49 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
45 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
57 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 ...
0
votes
3answers
121 views
Is EMC shielding of a grounding wire required?
Consider the following 2 use cases:
Fully electric vehicle with 2 different insulated voltage systems: 1 high voltage @1000V DC insulated from chassis and 24VDC system with minus pole (-) at chassis. ...
0
votes
2answers
59 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 ...
0
votes
1answer
36 views
4 Pole Connector and USB cable compatibility
USB 2.0 Cable to pass through enclosure boxes.
Are such cables able to be cut and connected (soldered) to the connectors pictured, and used without effect on their performance.
Are there specific ...
3
votes
1answer
59 views
Shielded Twisted Pair noise immunity
If I am correct in assuming a twisted pair cable is used to provide reduced susceptibility to noise. What is the benefit in having the cable twisted when it is inside a foil screen/shield?
Would ...
0
votes
1answer
51 views
Purpose of metal sheath in display cable?
I want to repair a display cable which I suspect has some broken wires. The cable seems to be wrapped in a metallized fibre cloth. (I don't know the correct name for it).
What purpose, apart from ...
1
vote
2answers
76 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 ...
1
vote
0answers
97 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 ...
1
vote
2answers
90 views
Shielding and Ground Loops - RF panel jacks for GPS
I've been working on a design that requires me to pass an RF signal through a conductive panel. I'm using SMA jacks for that purpose as they're readily available and also available in an isolated ...
0
votes
0answers
38 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 ...
1
vote
1answer
114 views
Faraday cage - reducing EMI?
I am curious about the working of a Faraday cage as the shield for EMI in many systems. As far as I studied, it depends on Faraday's and Lenz's laws.
When the electromagnetic waves are incident on ...
0
votes
1answer
67 views
How to use shielded audio cable with micro-fit molex connector?
This is typical shielded audio cable which I’m supposed to use with micro-fit molex connector. The problem with that cable is that the ground cable/the shield is not insulated and I found it very ...
3
votes
0answers
48 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 ...
0
votes
1answer
56 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 ...
2
votes
3answers
81 views
If a PEC surface completely reflects an EM wave, why doesn't an ungrounded shield work?
I was thinking about shielding and its effectiveness.
An ungrounded shield doesn't work well for either inductive or capacitive coupling.
However, if you think about plane wave theory, a PEC surface ...
0
votes
1answer
85 views
Could shielding (not grounded) affect signal integrity?
I'm trying to shield 6 flat cables that give me some communication issues because I thought that there might be cross-talk or other sources of interference that cause the problem.
The shielding is ...
2
votes
1answer
158 views
Motor / VFD / Protective Earth
I have little experience with AC motors since I'm majoring in Mech.E. My team is setting up an AC motor with a VFD to control the movement of an airfoil inside a metal cage we built. I understand the ...
0
votes
1answer
121 views
Shield ground to metal body or signal ground?
I have a question about grounding.
I will have two short shielded cables with signal wires inside, located at the top of a tower. The cables have a grounding wire inside shorted to their foil shields ...
4
votes
1answer
325 views
Ground planes disposition in Ethernet connection
I am designing a board that will have sensible analog signals and a processor communicating with the external word via Ethernet and I want to avoid that common mode currents couple into my analog ...
2
votes
1answer
140 views
Voltage detected across Micro USB cable shielding
I designed a Keyboard PCB using an ATmega32U4 with the data lines wired up to a Micro-USB B Receptacle. Brand: Molex; part number: 1050170001. The USB ground is directly connected to the Micro-USB B ...
0
votes
1answer
111 views
4 pin connector is melting even with 5 volt and 0.1 amp power supply, Why?
I am using a connector as shown:
.
I am using this to connect to my camera, which works at 5 volts and 0.1 Amp. But this connector works only for few days and then the plastic portion of the ...
4
votes
2answers
84 views
Why is shielding effectiveness different for various hole geometries?
I have run into the equation below in various literature/app notes. (example). I have never seen the derivation for such an equation and don't understand why round apertures are more effective at ...
0
votes
3answers
198 views
RS422 Full-Duplex Cable Shielding
I need to interface two PCBs via RS422 (250kbps) in full-duplex mode (4-wire, 2-twisted pairs 100ft cable). This system will operate in a noisy (CNC) industrial environment, ie, industrial controls ...
3
votes
1answer
156 views
Analogue (or digital) signal integrity with multiple sources of noise
tldr: Can I transmit an analog signal through a noisy environment without it being corrupted, or should I use a digital signal instead?
My requirement is to transmit a signal from a MA3 absolute ...
0
votes
2answers
180 views
Should I use shielded RJ45 plug by the computers? [closed]
If I have shielded cables, jacks and plugs and I ground the shielding properly, then should I use shielded plugs at the computer's site too? I mean if I do so, then the shielding will be connected to ...
0
votes
1answer
45 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 ...
0
votes
2answers
562 views
How close to a stepper motor do I need to shield the wires?
I am trying to shield the cabling on my CNC mill. The motors, unfortunately, do not have connectors but instead have wire leads coming out from the motor housing. I can cut those wires about an inch ...
0
votes
2answers
120 views
Strategies to reduce EMF radiation
During a long-term, almost six month long, data acquisition in a proximity of scanning electron microscope I have found a significant source of magnetic field noise, which is altering the results. I ...
0
votes
1answer
373 views
Effects of Neodymium magnets on PCB
I'm currently doing a project that consists of:
Arduino Nano.
Battery.
Buck Boost converter.
GPS module.
TSL2561 light sensor.
BH1750FVI light sensors.
LSM6DS3 Accelerometer.
HDC1080.
MicroSD shield ...
-3
votes
1answer
93 views
how can i attenuate mobile signal completely(maybe 90%) and please suggest me the wall thickness ,as i want to use copper or aluminium [closed]
please help me as i want to make a den for my dog that completely attenuates em waves of phone
1
vote
1answer
834 views
Why is the usb shield always tied to ground (GND pin)?
The shielding on a cable is to avoid interference from the outside world however it is always tied directly to the GND pin. Not inside the cable itself but inside a device. Every single device I take ...
0
votes
1answer
47 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.
4
votes
2answers
1k views
Long wires causing Raspberry Pi to die?
I've been working on a simple project involving a Raspberry pi and some switches.
I would never thought I would have any problem for something as simple as a switch, but here I am.
The 2 wires from ...
1
vote
1answer
770 views
Why do USB data cables have 5 wires, what is the use of shielding wire?
I have always been curious about the 5th wire(aka shield wire) in USB cables. What is its purpose? Does it anyhow affect charging speed for mobiles or data transfer?
I do know that it carries the ...
1
vote
1answer
202 views
USB shield for analog and digital ground?
I'm new to Mixed-signal design and I'm having trouble deciding how to connect my digital and analog ground. I'm doing a 4 layer design, so I have a split ground plane.
As I understand, since I'm ...
3
votes
2answers
61 views
Help Shielding RF Anechoic Chamber - FM Stations
a collegue and I acquired a surplus small anechoic chamber (8 ft x 8 ft) for making some pre compliance test measurements, and we're running into the issue of FM Stations being only attenuated around ...
1
vote
3answers
345 views
Using shielded audio cable for potentiometer sensor
I'm trying to measure a potentiometer from an Arduino's ADC. The potentiometer has a maximum value of 100k ohms and is located about 1 meter from the Arduino. The potentiometer's wiper is wired to the ...
1
vote
0answers
45 views
How does the size of a conductor affect a driven voltage?
I'm designing a capacitive sensor which uses an active shield to focus the sensing field. This much works well.
Now, in order to most effectively protect the active signal from noise I'd like the ...
2
votes
1answer
696 views
SD card connector chassis grounding
I have been designing a PCB which includes an SD card connector. As I'm not a PCB designer expert, I was looking for a reference design when I came across with the circuit bellow, extracted from Texas ...
1
vote
2answers
104 views
What does metal to metal bottoming mean?
Some connectors datasheets specify the following:
Metal-to-metal bottoming for maximum EMI shielding under extreme vibration
Reference: Dualok Connectors
I have also encountered the following for ...
1
vote
2answers
140 views
Does burying a cable shield it?
TL;DR: Does burying a cable provide shielding? I.e., is a shielded cable in air equivalent to an unshielded cable buried ~ 6 inches in soil?
Long:
I'm a technician at a university. I don't have ...
2
votes
2answers
954 views
Shielded cable, to ground or not, in amplifier
I have been looking for an answer on the net about this question but not found it fully answered. The topic has been up here a few times (see links below) as well but I find the answers lacking.
My ...
1
vote
1answer
173 views
How to shield a battery powered instrumentation with USB interface?
I would like to ask for advice on shielding the following setup.
I have a measurement target sitting inside a Faraday cage, connected through a shielded cable to a measurement circuit. The cable ...
1
vote
1answer
80 views
dip switch electric shield
I have ordered a Reed Relay with a diode and electric shield, but I am not sure how to connect the shield to the rest of the circuit because I do not know what the shield does and how does it work in ...
1
vote
3answers
101 views
Is there any sense in carrying assembled enclosed electronics in a static-shielding bag?
Say I have a Raspberry Pi enclosed in a metal case, such as this:
Would it offer any additional level protection if I put it in a static-shielding antistatic bag whenever I carry it around (e.g. ...
3
votes
2answers
287 views
How should I use a static-shielding bag prior to opening, and why?
After grounding the ESD mat and wearing the properly grounded anti-static wrist strap, what is the correct process to take the contents out of the static-shielding bag and take it onto the antistatic ...
0
votes
0answers
184 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 ...
