Questions tagged [interference]

For questions about electromagnetic interference (EMI); see also the [emc] tag.

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2-stroke engine interferes with Arduino project

I'm currently working on a bicycle project where I have mounted a 25cc 2-stroke (weedeater) engine at the rear of a bicycle. I have also created a speedometer (based on Arduino) which is mounted on ...
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2 votes
1 answer
107 views

PCB Ethernet instability - CM4 Breakout Board

I am creating a breakout board for the Raspberry Pi CM4 which should support Gigabit Ethernet and POE. I embedded a magjack onto the breakout board. I am struggling with the connection stability, ...
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Help with the design of a RF PCB transmitter

Edited with previous suggestions I work for a company that builds (redacted for privacy), and a big company lent us a special GPS anti-jamming device, and I am in charge of implementing and testing ...
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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 ...
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8 votes
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Radio static due to neighbor's shredder

I live in a condominium apartment building. I have a Bose Wave Radio with a dipole antenna connected. I frequently listen to FM radio stations. One of the stations I listen to has pretty good power ...
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Avoid body interference in a parallel plate capacitor

I'm making a parallel plate capacitor. Each plane is 4"x6" and they are separated at about 1cm. I am using an LC meter to measure the capacitance, and the results agree with the parallel ...
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Coax cable 130 dB vs 135 dB, which one is better?

I need to buy some coax cable for TV via satellite. I see they are marked in dB: 135, 130, 120 down to 95. Then there are multiple layers (up to 5) and shielding copper (cu) vs aluminum (alu.) Is my ...
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LCD scrambled by interference from RF plasma

My lab uses a custom-built setup to generate reactive plasma; basically metal plates in a vacuum desiccator energized by a BD-10A. I've built an arduino-based control box for it to allow more precise ...
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Two devices sharing the same coaxial cable, what frequency channel should I chose? [closed]

The 2-stories house is equipped with a coaxial cable that has wall plugs in 1st and 2nd floors (it's also connected to the antenna on the roof). Our IAP installed a modem for Internet (Arris CM820C) ...
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Can inductors interfere with a BLDC motor?

I'm working on a student project. It involves running a brushless DC motor with 70uH external unshielded inductors on each phase. Can the inductors, seeing as they generate a magnetic field, somehow ...
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Interference effects on a wireless signal

I am trying to get my head around the effects of interference on a wireless signal and its signal strength. I do not have an engineering background, but I do have a background in wireless sensor ...
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Can I mix three wires that carry single phase 240V AC and four wires that carry USB signals into a signal custom cable?

I am planning to design a system that requires AC power supply as well as a USB connection. I found a connector that has provision for the same here. If I were to pass 240 VAC single phase along with ...
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3 votes
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Roughly how fast can a constant current LED circuit ramp to 1A without EMI issues?

I have a constant current circuit supplying a 1A LED for a carefully controlled strobing application; for my application the LED needs to turn ON (no dimming) for ~1ms and then OFF (fully off), at a ...
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Is the amplitude of the sum of 2 transmitters of white noise at a given frequency greater than each individual transmission?

If you have two antennas \$T_1\$ and \$T_2\$ each broadcasting 10GHz Gaussian White Noise at the same receiver, each with an EIRP of say 20 dBW with a random phase offset between them, then is there ...
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Running and grounding paired shielded cable thru a connector

I need to run two logic signals around a vehicle, so for good measure, regardless if its overkill or not, I want to use a shielded single pair wire for that job. At one point it should be crimped to ...
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NFC and magnet interference in a concrete piece

Do you know if both NFC and a magnet would work correctly in this scenario? I´m designing small pieces of concrete (imagine chess pieces) with three layers: magnet inside, NFC tag in the middle, and ...
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Flashing random LEDs when multiple wires fished through hole

I've been building a large, 3D printed dodecahedron infinity mirror. Prior to adding the polycarbonate pentagons with mirror film applied, the LEDs worked perfectly in the frame. Once I fished the ...
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What can negatively impact a motherboard's / CPU's clock generator / oscillator?

Is it possible for a clock generator / oscillator to be skewed by something from the electrical grid (e.g. to work perfectly fine at place A, and have issues at place B - all reproducible)? What would ...
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Bluetooth antenna on top of large metal object and other RF questions

I've been doing some research on RF antenna design considerations but haven't really found anything close to the situation my device will be in. I am designing a wireless sensor for my FSAE team that ...
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RF interference in high node density 2.4 GHz networks

These days, there are a lot of products that are working on 2.4 GHz RF - mobiles, laptops etc using 2.4 GHz wifi, earphones using BT, home automation products using 2.4 GHz zigbee. Though these ...
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How best to allocate signal wires to 4 twisted pairs that best reduces inteference

I have to transmit digital signals 30meters including power. I am going to use a cat 6 ethernet cable with 4 twisted pairs (8 wires in total). I can already assure that my signal gets to the other end ...
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3 answers
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Relay is switching by touching optocoupler with finger

To switch a 12V relay with a micro controller, I designed ("borrowed") this schematic. Build the pcb and it works great. But there's a little bug that got me a bit worried. If I touch the ...
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Desktop screen goes black because of radiowaves from phone?

I hope this is the right community for this phenomenon. For some weeks my desktop screen went black for some seconds - no warning prompt no nothing - and then came back to life. I usually change my ...
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How to stop LED EMI on capacitive touch sensor TTP223

I am trying to make a piece of wood touch sensitive. I have a piece of wood carved with runic letters. I inserted LED's inside then filled the letters with epoxy resin. When I touch one I want the ...
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RF line: routing it orthogonal over SPI digital signal lines

SPI will be kept below 1MHz. RF signal is under 434 MHz. Is this crossing fine through the big zero ohm resistor ? Side question: will the outermost SPI line (it is the chip select one), or any of the ...
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Why does analysis indicate that ground lifts do not fix ground loops?

Note: "Ground loop" in this question refers to a ground loop caused by linked magnetic fields. (Sometimes ground loop refers to slightly different scenarios.) Recently I've been looking into ...
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3 votes
1 answer
103 views

Oxygen sensor voltage changes when machine is powered on. Interference?

I built an Arduino Uno based control panel for an altitude training machine, which connects to an oxygen sensor. The value is amplified by an instrumentation amp (INA122P) and read into the analog ...
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3 answers
69 views

Better to Opto-Isolate on Sending or Receiving End? Isolating to Avoid EMI

I am working on an art project using some modified bug zapper circuitry to produce loud and bright sparks. I have the circuit working and the sparks are very impressive, but I'm running into a issue ...
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2 votes
1 answer
70 views

Protecting against static interference/noise for encoder

I have a chassis that is made from box steel beams, they are painted/surfaced. Attached to it is a fiberglass tub which can rotate. Attached to the fibreglass tub are supports and mounts where some ...
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Why does my Ethernet upload speed go to 0 Mbps when connecting an RGB LED strip?

I recently installed the following RGB LED strip on my bedroom's ceiling: The computer and the lights share the same electrical connection. However, everytime I plug the lights into the wall my ...
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2 votes
2 answers
225 views

Best configuration for ethernet-as-speaker-wire?

I'm hooking up a couple of small speakers (3w max each) outside, and I have a small run in my house from inside to out that was done with ethernet cable. There's no way I can pull speaker wire through,...
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1 vote
1 answer
253 views

Power Supply issues with CAN bus

I am currently working on a system using C# for a windows GUI with an Ixxat USB-to-CAN and an STM32F303K8 that runs CANopen, The system itself is running fine I can send and receive messages to and ...
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3 votes
2 answers
267 views

I2C gets Interference from motors in an Arduino project

I built a small Arduino "robot" on a tracked chassis. The device uses MPU-5060 for direction finding (on a prototype shield) and Adafruit MotorShield v2 to control two 320-type motors. The ...
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2 votes
1 answer
140 views

SMPS grounding interference ... ground loop maybe?

I am experiencing a weird phenomenon with my class 1, 15 Volt, 1000 watt SMPS with an isolated input and output grounds. The AC input (PE) ground connection has continuity to the SMPS chassis. When ...
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Is it ok to have two stepper motors right next to each other?

Would there be any issues having two nema 23 stepper motors laying right next to each other, facing opposite ways (see image)? 48v, 4amps.
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3 votes
3 answers
325 views

Decreasing I2C SDA SCL interference

I am setting up a fast I2C communication between a microcontroller (STM32, master) and an FPGA (Zynq-7000, slave). Currently, it won't work correctly because whenever the FPGA pulls down SDA, it ...
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2 votes
1 answer
111 views

DIY electromagnetic shielding (CNC mill)

I'm building a DIY CNC router. I'm running at a low RPM and only planning on cutting soft materials (wood and under, maybe a PCB). I'm currently having problems with magnetic interference. When ...
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1 answer
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LTC5599: why are these baseband inputs passed through 49.9 ohms and the capacitor + SPI

I'm designing a radar transceiver board using the LTC5599. In the datasheet for the part, there is a schematic that shows the circuit configuration for the evaluation board. Here is an image of the ...
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1 vote
0 answers
62 views

IR reciever somewhow being triggered by cell phone screen?

First time asking a question here. I am curious why the TSOP4838 ir sensor is acting eratically when my Google Pixel 2's screen is facing it. As you can see from the schematic, I have a 555 arranged ...
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0 votes
2 answers
76 views

Shielding an RF module from noise

I feel like a fool. As seen in the image below, the nRF module is right next to the VIN terminal. When I powered this up, I was able to communicate with the nrf module via SPI but it wouldn't receive ...
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Cross-Talk/Interference between UART Lines on a PCB

I am wondering at what distance UART lines begin to interfere with each other? And can I expect the UART lines below to function properly? The PCB board below has 6 UART lines running alongside one ...
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51 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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1 answer
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How to know which radio frequency is free to transmit data over a particular frequency to avoid interference

I found that some radio broadcasting stations transmit data at a particular frequency, and I was told that if I were to transmit my own at that particular frequency that I would interfere with their ...
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2 votes
2 answers
287 views

Shielding powerful HF EMI

I'm trying to install a plasma cutter on a CNC machine, but the problem is that the cutter uses a high-power HF start to initiate the cutting arc, and this causes horrible interference with my control ...
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  • 370
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Multiple AC-DC power supplies or use DC-DC converters and one power supply?

I have an electrical control box that needs 48v, 12v, and 5v to power stepper motors, sensors, and microcontrollers, respecitvely. All power items will be mounted on a DIN rail right next to each ...
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0 votes
1 answer
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Correct model for interference from an unterminated transmission line branch

Question about the correct mathematical model for a branched transmission line Baseline Setup Waveform generator: Output 10-60MHz sine wave, 8Vp-p, Output impedance 50Ohms RG58 50Ohm coax: ...
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3 votes
1 answer
2k views

What types of cables do ferrite beads/chokes have a beneficial effect on?

Ferrite beads prevent electromagnetic interference from affecting a cable. Without fundamentally understanding how EMI works, this is obviously a beneficial effect for the stability and integrity of ...
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0 votes
1 answer
35 views

What's the logic inside the formula for the calculation of the maximal envelope modulation amplitude of two temporal interfering electric fields?

Since my question is a bit elaborate, I will first write some details. Thank you all! I refer to the study conducted by Nir Grossman et al. (2017) about the use of the temporal interfering stimulation ...
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0 votes
2 answers
155 views

Arduino resetting or malfunctioning when controlling 48V DC motors with relay module

I'm building an Arduino controlled crane machine out of old crane machine parts. The motors in a crane machine are 48V DC and I am controlling them with an H-bridge configuration using an 8 channel ...
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Do I2C wires and 120W (12V) power wires close together cause trouble?

I'm a beginner with electronics and I'm building my first solar powered robot. I now have a 50cm long (1.6 feet) small pipe through which I want to put four wires; 2 for the power from the solar ...
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