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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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2answers
117 views

Testing conductive RF shielding paint with a VOM

I heard it claimed that you cannot test the conductivity of conductive RF shielding paint with a Volt / Ohm meter. This was in reply to someone who had done so and claimed that the paint was ...
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1answer
173 views

USB3.0 Shield connection

In the below image for Amphenol GSB343K33HR, do the 4 rectangular pads in the center of the image signify Shield connections?
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2answers
3k views

CAN BUS cable Shielding effectiveness

I am asking a question on behave of a colleague who's struggling with the following. Does the relocation of the ground bonding point on a CAN bus ground shield make a difference? In the photo below ...
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0answers
156 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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2answers
481 views

Why is a shielded cable not effective with high impedance sensor?

Could some one simplify what this means? Why is the shielded cable not effective with a high impedance source/sensor?
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2answers
1k views

Design Considerations for Electronics in Space [closed]

What additional constraints do we face when designing electronics/microsystems for use in orbit? What kinds of shielding techniques are employed? Is it common to enclose all electronics in a faraday ...
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1answer
433 views

Which isolated ground should I use for an RF can/shield over an optically-isolating component?

I'm building a PCB that uses an optically-isolated voltage-sensor IC which takes an input voltage of -0.2V to 0.2V on one side and generates an isolated, proportional output that ranges from 0V to ...
4
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1answer
1k views

Making aluminium conductive for an RF shield enclosure

I'm not sure if it's appropriate to ask here, but I would assume many people in electronics would have experience with this. I'm enclosing an RF sensitive PCB into an sealed aluminium enclosure. ...
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1answer
997 views

Wireless Power Coil - Is this shielding? Field shaping?

I'm taking apart a Qi wireless power transfer receiver. The coil is etched into the pcb. The entire coil area (approximately 3.75 x 4.5 cm) is covered by a rectangular piece of hard, brittle material. ...
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1answer
3k views

Homemade shielding of a wire to a capacitive sensor

I'm using a capacitive sensor CAP1188 with Arduino, connecting 8 of its touch sensor inputs to 8 copper boards that I want to be the actual touch surfaces. The wires to the sensor are quite long (100 ...
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3answers
7k views

How to Connect USB/Ethernet Shields to Chassis or Digital Grounds

I have a PCB with a few USB and RJ-45 Ethernet connectors on one side. I'm quite confused as to how exactly I'm supposed to be hooking up the SHIELD pins on them though. This is for a host device ...
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2answers
101 views

Shielding effectiveness system

I've been working on a Shielding Effectiveness system of 120dB according to IEEE299-2006 standards. The frequency range covered is 9kHz to 40GHz. I've designed it using an analog signal generator, ...
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3answers
1k views

Are RF shields necessary?

I see that some wireless devices like Bluetooth speakers don't use shields like this one but some do. My understanding of FCC Part 15 is that only modules need shields. So how come some devices use ...
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1answer
175 views

Should cable shield connect to ground plane on hand-held tethered device?

I am designing a hand-held device whose power and signals come from a cable. The device circuit will be +5 volt and powered through the cable. The cable (a re-purposed HDMI cable) has multiple ...
4
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1answer
2k views

What is the effect on noise immunity of a floating shield on a shielded twisted pair

We have an installed system where resistive sensors are connected to some electronics by shielded cables of between 2 and 10 metres. The cable is a twisted pair sheathed in a stainless steel braid. ...
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2answers
918 views

SATA over unshielded cable

I need to connect a SATA device to a development board which does not have a dedicated SATA connector but exposes SATA over a common 2x30 female header instead. My question is what cabling do I need ...
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2answers
771 views

Shielded cables to capacitive sensor?

In a hobby project I am using shielded cable to connect capacitive sensor's electrode (see https://electronics.stackexchange.com/questions/189916/capacitive-touch-not-working-at42qt1011 ) to the ...
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2answers
804 views

Ground loop Isolation transformer, alternative?

Most of those transformers are a bit costly in my region(India). is there any alternative solution that can be employed. Application in audio amp. I was thinking maybe use a step-down and step-up ...
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2answers
2k views

How to shield multiple flat (ribbon) cables properly?

I have a situation where I need to connect 10 flat cables (20 way, 0.625mm pitch) to special PCI-E card in my computer. They go from PCI-E card on back to drive bays in front of computer case. Those ...
3
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1answer
267 views

is it safe to have hot wire connected to ground (metal case, shield) via a capacitor?

I have opened a psu, and I saw a small capacitor is connected between one of the ac inputs and to the ground/shield. We don't have ground in our ac outlet, so a hot 110v ac line could be connected to ...
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1answer
483 views

Don't RF devices need to be shielded to pass FCC?

I'm looking at this device. Internally, the Bluetooth chip isn't shielded but it still seems to have passed FCC. Addition to that, there was no Modular Approval Request Letter, which typically ...
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1answer
69 views

Metal Effect on Trace Impedance and Ground

I am working on a project that will have some impedance controlled traces running next to a large metal plate grounded at 1 point. I wanted to confirm that: 1) The metal plate will still impact the ...
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2answers
2k views

Coaxial cable vs shielded pair

I need to wire a sensor with analog output to an acquisition system, and the presence of a separate "shield" connection on the DAQ made me thinking: why would I use a shielded 2-wire cable versus a ...
3
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2answers
1k views

How to design a metal plate for PCB

I am designing a Esp8266-based WiFi module and I'm not sure if I need one of those metal plates. They are suppose to protect a sensitive area from EMI/RFI, right? Also, how can I design one with ...
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1answer
490 views

Connecting shielding for high and low voltages

I have design a power distribution PCB with high AC(230V) and low DC(<10V) voltage power rails. Both are going to be connected to my board by separate cables. Each of those cables have shielding ...
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2answers
2k views

Why does a radio still work inside a metal box?

I've put a small battery powered commercial radio inside a Quality Street tin. The tin is all metal with rolled joints and the lid is a tight fit. I'd be willing to bet that there are no holes ...
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2answers
564 views

Is this pcb layout good practice?

I saw a PCB with something like this. A trace that connects the four holes on the corners. I assume that they do it to prevent some kind of noise. I am not sure if the connect that trace to GND Also, ...
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1answer
146 views

questions on shielding static magnetic field

It seems that using ferromagnetic materials is the easiest way to shield static magnetic field. But is it still working in strong field strength(up to 5T)? Another question is that are mu-metal (iron-...
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1answer
455 views

Should I using ground pours to surround high speed lines?

Previously I've been using ground plane pours in Eagle to connect ground points and also to surround lines that I feel need protecting from surrounding noise. This is on two layer boards. By drawing a ...
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1answer
1k views

Portable device shielding & ESD

I'm working on a portable battery-powered device with a shielded I/O connector for sensors, but I'm confused about how to properly ground the shield and ESD array. Here is a block diagram of my ...
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2answers
120 views

What can be used for impromptu EMF shielding?

I have a robot with a lot of servos in close proximity and a high-current DC motor powering an airsoft gun. The motor is causing electromagnetic interference with the servos, and we need to shield it ...
2
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2answers
1k views

Sensible standard wiring type for long-range I2C

I'm planning on interfacing with some sensor devices via I2C over a long bus, with devices chained every 2m or so, up to 16m in total. I've seen other questions here referring to this from the "which ...
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1answer
94 views

Shielded sleeve?

Does anyone know of sleeving that is basically a hollow tube with a metal shield? Something like coax but without the core? I need to take some unshielded wires and run them through a flexible RF ...
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1answer
160 views

EM compatibility of single board computers and laptops

Like a lot of people on this site, I own some single board computers (SBC) and microcontroller boards (UDOO, Raspberry Pi, Arduino, Atmel boards, etc.). I wonder about the electromagnetic emissions ...
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1answer
523 views

Can a metal pipe shield wiring against EMP during a nearby lightning strike?

I have a building which regularly experiences nearby lightning strikes. The backup diesel generator is located 10 meters away from the building. Can induced currents from the EMP be reduced within the ...
3
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1answer
420 views

How much shielding does an ungrounded metal box provide?

How much shielding does an ungrounded metal box provide? That is, a circuit is in a metal box but the box is not connected to either circuit ground nor externally earthed
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2answers
1k views

unbalanced audio - shielding and ground loop for 2 ch

I have a 3 conductor wire that are all wrapped in a foil shield with wire conductor, for a total of 4 wires. I am connecting the 3 inside wires to audio left, right, and ground. This is an unbalanced ...
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1answer
275 views

why is the ic rf shielding exposed

I assume this rectangle around the IC is for RF shielding, but why when is it exposed? I have seen this occasionally and I am not sure of it's exact purpose or why its exposed. Googling the title ...
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1answer
1k views

Shielding a long cable

I was reading about the LM35 and i found this, he suggested that i must use shielding over long distances, which makes sense, but then he said i must add a capacitor and a resistor, why did he add ...
2
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1answer
395 views

RFI on the amplifier due to Wifi

I have a board with a sensitive analog amplifier. This amplifier is optical in nature and it has a gain of 6M times. On the same board there is a Wifi module. Somehow when Wifi is transmitting I see ...
4
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2answers
202 views

Thickness of low frequency Mu shield calculation

I am dealing with a low frequency varying magnetic field, say 10 - 100Hz with a magnitude of 0.8T. It seems shielding at this frequency gets tricky. Even though Mu is capable of doing it, there should ...
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1answer
259 views

Shielding not connected to USB connector causes tablet restarts

I have a custom USB cable, USB type A male on one end and a DB-9 connector on the other end (only using 4 pins). The shielding of the cable is connected to the USB connector but not the DB-9 connector,...
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2answers
1k views

How to maintain EMI shielding whilst penetrating the shield with cables?

I'm trying to shield an ip camera from EMI generated image noise for low light photography. It's enclosed within a metal box that is then grounded. The subject is also inside the box. The camera ...
3
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1answer
2k views

Is it OK to place ground plane under transformer?

I have a large transformer (50kHz, ferrite E-core) on the PCB. I want to pass power rails under it on the bottom layer. Should I place a large ground plane on the top layer to shield these power rails ...
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1answer
288 views

Using shielded cable on an ebike hub motor, what ground to use

I have been having strange issues with an ibike that I have built, in that interference keeps being generated from the motors phase wires into the RX/TX lines on the hall sensors. I have been advised ...
3
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1answer
1k views

Passing USB signal over short SATA cable and connector

I am working on a prototype device and I will have a daughter-board mounted at an odd angle in a custom enclosure. I need to get a USB signal, and a few extra GPIO type wires, over to the board. I can'...
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2answers
3k views

Shielding for Load cells

I am currently having a lot of trouble with noise being picked up by load cells. The strain gauges on the load cell are configured in a full-bridge pattern. In a noiseless environment (ie far away ...
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5answers
4k views

What are these metal plates covering parts of PCBs called?

I am trying to fix my wireless router, but one of the parts is under a metal plate. What are these metal plates called? This is what it looks like when it is removed: (The gold coloured plating ...
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2answers
967 views

eliminate noise pickup from shielded enclosure's surface

I have a test instrument that measure spectral energy density versus frequency. The measurement is extremely low noise. The RF input on the test instrument is an SMA-connector where the inner ...
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1answer
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 ...