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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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682 views

Magnetic shielding

http://www.kjmagnetics.com/blog.asp?p=shielding-materials I understand from the diagrams that the magnetic field is redirected through the shield (and not canceled out.. etc) Suppose I cover one ...
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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 ...
2
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0answers
4k 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 ...
3
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2answers
3k views

Does the “drain” wire in a microphone audio cable serve any purpose the shield does not?

I'm helping a friend with an audio installation, and he asked about the requirements for the microphone cable: "Wiring Requirements: 2 Conductor shielded cable, 22 gauge with a 24 gauge drain wire. ...
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1answer
2k views

Does it matter if I shield the antenna wire or the interference source

I have a problem. My car radio is picking up interference when ever I plug a device into the power outlet/ cig lighter. I know that the solution would be to put shielding around the antenna wire, but ...
4
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5answers
6k views

Shielded vs Twisted cables

For some reason low voltage, high quality audio interconnects seem to be made of 3 wires braided together, when normal low voltage audio wires are two wires surrounded by a grounding sleeve. I'm a ...
4
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1answer
619 views

Shielded cable vs. unshielded in underwater environment

I know basic electromagnetic theory very well and understand why this works but I'm not sure about one thing regarding usage of coaxial (shielded) cable vs. unshielded (normal conductor) cable when ...
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1answer
2k views

Noise reduction in physiological measurements (EEG/ECG) [duplicate]

I am building a hobby EEG and I am interested in quantifying how effective are the various noise reduction techniques. The basic circuit would be two electrodes going to an instrumentation amplifier. ...
15
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2answers
2k views

Grounding PCB to enclosure

I am designing a small sensor which fits into a custom aluminum enclosure. The sensor uses CAN bus and a long cable to connect it to the host and power. The shield of the cable will ground the ...
4
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2answers
1k views

Where to connect shield and ferrites in PCB with isolated planes

I have a device which has two sections of the PCB completely isolated form each other, but connected by an isolator IC (PN: ????). I think I need to shield the whole device for reducing EMI because ...
2
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1answer
2k views

Digital Compass: Can it be calibrated/shielded to prevent normal operation in the presence of ferromagnetic materials

I am currently working on a hobby project, for which I would need a reliable compass that should work in as wide a range of environments as possible (i.e.: In a field, in a car, on a train, possibly ...
3
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1answer
1k views

Benefits of top and bottom ground pour in multilayer boards with proper ground plane layers and stackup

I'm trying to get some analytical feeling for the use of ground pours on bottom and top layer in multilayer boards with proper stackups such as (for example). Top Gnd Sig1 Power Power Sig2 Gnd ...
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3answers
2k views

Can I safely enclose battery-powered electronics in an antistatic bag to protect it from static electricity?

I am building an enclosure for a Beaglebone and external circuit that I want to be able to wear, and therefore want to be lightweight and somewhat comfortable. I power the Beaglebone using a battery ...
2
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2answers
6k views

Help with the design of a rectangular loop antenna for the PN532 controller for NFC communication

I am currently designing an NFC reader in the context of my PhD thesis. The NFC reader will use a PN532 chip from NXP (which is one of the requirements of my circuit). I plan to draw a rectangular ...
6
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2answers
2k views

Faraday cage mathematics

We all know the Faraday cage effect: light waves get through the screen on the front of your microwave oven, because their wavelength is much less than the size of the holes, whereas the microwaves ...
9
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7answers
7k views

Why does an XLR connector use 3 pins instead of two

Why does XLR connectors use 3 pins instead of just 2. The wiring is Pin Function -------------------------------- 1 Chassis ground(cable shield) 2 hot 3 cold ...
4
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4answers
262 views

Energized circuit in a 3M Static Shielding Bag (silver color)

I'm wondering if it's safe to put an energized circuit in a static shielding bag...as part of a high altitude balloon project. I'm not too sure how these work, so I tried seeing if either the outside ...
31
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3answers
4k views

Correct place to attach shields for twisted pairs

I have two PCBs connected by a cable containing 5 sub-cables: 6v power through a custom made coaxial cable (similar to that found on laptop power supplies). 2x 100mbps LVDS through 100ohm impedance ...
4
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2answers
5k views

EMI/RFI emissions and computer cases

I have designed a computer case (enclosure) for mini-itx motherboards. Its bottom and rear are made out of 2mm thick aluminium and the sides and top out of 4mm plastic (ABS). I'd like some advice ...
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3answers
216 views

Why would this wire be shielded?

I'm trying to work out how I might emulate this assembly to replace the seat weight sensors below. I'd guess the sensors are just strain gauges, so a variable resistance or maybe capacitance. ...
6
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2answers
1k views

How is this crystal / ferrite bead / ground shield connected?

This is part of the schematic for a TI TAS1020B USB Streaming Controller MCU that I don't quite understand. Obviously the shield connects to one end of the ferrite bead, but what else? Are the XTAL ...
2
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1answer
1k views

Connecting the Shield of a strain gage cable connector to PCB with ADC

I have a half-bridge strain gage sensor (pre-assembled product) with a 30cm cable, which I am trying to interface with my PCB containing a 24-bit ADC. The connector at the cable end toward the ADC (i....
8
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1answer
2k views

Proper shielding techniques for chassis grounded equipment located 30 feet apart

I am just hoping to get some best practices out of this discussion: I have two pieces of equipment that are located about 30 feet apart and bolted to a metal frame (chassis ground). They interface ...
4
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1answer
922 views

Best practice design ground and shielding

Case: I design a pcb with a microprocessor and a adc (I'll leave out the details). Is this correct: The digital ground and the analog ground should be connected, but by a small passage. Next ...
5
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3answers
168 views

Running router out of its case

I'm currently building a robot, and as part of its spec it must connect to a wifi network. I have a Belkin wireless router, which I have taken out of its case to expose the PCB. My question is: Is ...
9
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2answers
2k views

How to check whether a component can work in strong magnetic fields?

I want to design my PCB to operate nicely even when we place it next to a neodymium magnet. How to check whether my component can work in such condition without shielding? Edit: I haven't face any ...
4
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1answer
4k views

How can a shield winding in the transformer be helpful without fully covering the core?

This article describes the Apple iPhone charger circuitry in great details. It mentions the shield winding in the flyback transformer. The shield winding is simply an extra most outer winding and the ...
9
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3answers
22k views

How important is the shield on an RJ45 connector?

If I am going to use a PCB mount RJ45 connector for 100mbps Ethernet, does it need to be a shielded connector, or can I get away with using an unshielded one? Is there some standard which deals with ...
4
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5answers
13k views

How do I shield a card like Visa payWave and MasterCard PayPass to block its communication?

This is basically a replication of this question on Personal Finance SE. Suppose there's a wireless smart card like Visa payWave or MasterCard PayPass or MIFARE Ultralight. The owner wants to ...
4
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1answer
1k views

DVI Shield pins

Should I connect the Shield pins 3, 11, 19, and 22 on my DVI connector to GND on my PCB? What consequences might I expect if I leave the shield pins floating?
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2answers
2k views

How can extend the cable distance from a condenser microphone to the ADC without loosing fidelity?

I am new here so please forgive me for a vey basic question. I have a TASCAM iM2 in my possession. This is a stereo condenser microphone coupled to an ADC that connects to the the latest iPhone models ...
10
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3answers
2k views

Shielding and Ground loops

I have various pieces of equipment that all need to be connected to GND (Chassis GND). The issue I'm having is that I'm connecting an ADC card inside a computer through a metal box with custom ...
29
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6answers
12k views

Noise reduction strategies in electrophysiology

When recording electrical signals from cells (in a dish or inside a living human or animal body), one major problem is to increase the signal to noise ratio. These signals are usually in the 10uV ...
6
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2answers
2k views

Aluminum project box: should BNC conenctors touch it?

I want to make a aluminum shield box (this is my first time!), I made some holes to host some female BNC connectors. Now my question is, should I isolate the BNC connectors from the box? Or should the ...
0
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1answer
313 views

Coaxial and Triaxial connectors

Can the coaxial cables be connected to a triaxal connector and other way around? I am asking this because I have a instrument that has BNC connectors, but I want to use triax for extra shielding. If ...
19
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1answer
2k views

Shielding can, what is the proper way?

I like to protect a sensitive circuit of mine with a shield. I don't have a picture but basically, I have put together a 1 mm thick ground rectangle on the top layer, and I will place the shield ...
4
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2answers
733 views

What types of Shielding and Filtering would allow devices to be used in a MRI environment?

I'm working on a respiration monitor and I was wondering what area of electronics I would need to get familiar with to design the hardware filters that would stop the RF/EMI from frying the system. ...
6
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1answer
6k views

How do I shield my pc-speakers from mobile interference? [closed]

I have a budget (not cheap :P) pc-speaker set from Logitech (2.1) at home which are extremely sensitive to cellsignal interference. My iPhone is about 1m from any part of the set - including the ...
11
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2answers
2k views

Can a shield propagate EMI?

At a job site we typically have 10 vehicles connected to a single vehicle (star layout) by a 100m 5 conductor cable carrying power(unused), ground, shield, CANH, and CANL. The shield is grounded on ...
6
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1answer
1k views

Running network cable near X-Ray equipment

My mother runs a small veterinary clinic. She is getting a new X-Ray machine that will need a network connection to send digital copies of the X-Ray to the server. I will be installing a wall plate ...
53
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12answers
64k views

How to connect USB Connector shield?

How should I route USB Connector shield on PCB? Should it be connected to GND plane right where USB is placed, or should the shield be isolated from GND, or should it be connected to ground through ...
5
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3answers
5k views

Non-metal cases

This question is really aimed at computer cases, but I suppose it also applies to other PCB cases. Most of the Computer cases I come across are aluminium, or else some other metal; As I understand it ...
6
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6answers
1k views

Shielding Techniques for Digital Sensor

What shielding techniques would be best suited for a digital sensor (3 wires - Pwr, Gnd, Sig) in a noisy environment (specifically fluorescent lighting)? Twisted pair (trio in this case) works well ...
6
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3answers
229 views

Wire to use with Sensors

I am trying to minimize interference in a sensor project. Can anyone recommend a good shielded wire I can solder into my board?