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Questions tagged [interference]

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

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23 votes
2 answers
7k views

Why are many IR receivers in metal cages?

I'm guessing it's a Faraday cage around the receiver, but don't know why they might need one. Is there some sort of common interference around 38kHz (their operating frequency)? It's the only ...
R Zach's user avatar
  • 345
31 votes
5 answers
28k views

What is causing large oscillations in my DC/DC boost converter? Is this ground bounce or some other effect?

I designed my first PCB for a DC-DC boost converter only to find that it produced very noisy output. The design is based around the MIC2253. Here's a schematic: Although my circuit allows for ...
Dave.Mech.Eng's user avatar
7 votes
2 answers
2k views

USB shielding, device or host side?

I have an SBC with a USB host port, but it is exposed as male header pins rather than a female USB port. I have soldered female headers to a USB cable and have a working but intermittant connection, ...
davegravy's user avatar
  • 439
12 votes
6 answers
3k views

How to avoid interference in wireless communication?

I am working on wireless communication system. We are using around 10 pairs of transmitter and receivers. We are using atmega16 microcontroller for encoding and decoding by USART ports. Now we are ...
user934070's user avatar
8 votes
1 answer
3k views

Killing GSM Buzz with Ferrite Beads

I'm trying to rid my speakers of the typical buzz from my iPhone. I get poor reception in my apartment and so it's constantly trying to find a signal, meaning I get a near-constant buzzing when the ...
Luke's user avatar
  • 81
8 votes
1 answer
12k views

Permanent magnets near wifi device

Background I have a small circuit that consists of a microcontroller operating on 14Mhz and a wifi module. This circuit is enclosed in a small plastic box. I am considering gluing a few magnets on ...
Amir Gonnen's user avatar
1 vote
2 answers
2k views

Would twisting 3 wires together be as effective (or close) to a twisted pair?

Would twisting 3 wires together like a twisted pair would be as effective as an ordinary twisted pair? Or at least a definite improvement to not twisting them at all? simulate this circuit – ...
DrakeJest's user avatar
  • 917
1 vote
1 answer
951 views

I2C on FFC or IDE cable - interference?

This is a follow-up question on this answer. I need to communicate with I2C over approximately 10cm and I'd like to use an FFC or IDE cable for that. Earlier, I used an FFC cable to link a segment ...
user avatar
0 votes
1 answer
527 views

What could be causing this interference and how to eliminate it?

(update: Please also see the major edit at the end) A sensitive electronic equipment Device 1 below is basically composed of a power line EMI filter at the mains entry, an SMPS power supply which ...
user1245's user avatar
  • 4,333
-1 votes
2 answers
1k views

Cable type and decreasing EMI/RFI

I am interested which cable/wire type is better to protect against electromagnetic and radio interference/leakage of signal. Is a twisted pair wire better than an untwisted, to protect against EMI/...
Jensen68's user avatar
18 votes
4 answers
10k views

Microcontroller with a long wire for digital input

I have the doorbell button on my house wired into a GHI EMX dev board. The software evaluates the time of day and determines whether or not the doorbell should ring. Side Note: This was ...
Matt Ruwe's user avatar
  • 1,997
18 votes
1 answer
418 views

Unusual interference

I'm experiencing an effect somewhat like GSM frame-rate audio break-through in my audio systems - completely different frequencies but equally wideband. I've noticed it occasionally in the past - ...
Russell McMahon's user avatar
  • 151k
11 votes
10 answers
6k views

EMI: CFLs vs Incandescent Lights in Your Lab?

Being a green-oriented treehugger, I've put in all CFL lights in my house. Just as much light for about 1/4 or 1/3 the power. Nice, but flourescent lights put out a lot of EMI. Does this cause ...
8 votes
3 answers
2k views

What Regulatory Requirements are Really Necessary for Sale in the USA?

I understand that unless you fall into some specific product categories that are exempt from FCC regulations, electronic products sold in the US are legally required to meet FCC EMC limits. However, ...
bt2's user avatar
  • 3,844
7 votes
3 answers
2k views

Sizing an RC snubber

My fridge is sending bad clacks to my loudspeakers when it turns on/off, I fear for the tweeters. I'd add a snubber/suppressor to the compressor but my notions about RC filters from school are 15 ...
Damien Pollet's user avatar
5 votes
3 answers
7k 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 ...
Chris2048's user avatar
  • 415
4 votes
2 answers
4k views

Guitar picks up computer interference

Years ago I bought a computer case because my other one was getting too small for the components. After moving all of the parts and booting up, one of the first things I noticed was that my guitar ...
Alex's user avatar
  • 41
3 votes
2 answers
5k views

Using Cat5 for DSL from NID - good idea to double up wires for signal integrity / strength?

I am doing some rewiring of our internal phone lines (almost entirely removal of unused lines). The issues we have run into is the router will every now and then simply not connect from the house to ...
Simurr's user avatar
  • 145
2 votes
2 answers
623 views

Fixing power supply interference issue (?)

I am working on a project that involves controlling WS2812B led strips using a Teensy 4.0 microcontroller. I got everything working during the testing phase, but now, after transitioning from ...
hmmmniek's user avatar
2 votes
2 answers
372 views

What's the suitable wire size for 9VDC @25 Amps line?

I am trying to put together the requirements for a cable and I was wondering what would be the most suitable wire size to load the DUT with 25Amps @ 9VDC. I will have few other high current lines ...
Rav's user avatar
  • 71
2 votes
1 answer
587 views

Two 2.4GHz radio modules (XBee+Bluetooth) on same PCB. How to minimize interference?

I'm designing a PCB with XBee radio module and a bluetooth module (RFDuino SMD with XBee 2mW Radio). Since both of these modules are using 2.4GHz, are there any special consideration about how to ...
flopr's user avatar
  • 135
2 votes
1 answer
1k views

LC Filter for Phase Control

Can you point me to a good online resource to learn how to understand and design LC filters? The goal is digital forward phase control to dim a light bulb. I've read that the EMI produced by the ...
Isaac Sutherland's user avatar
1 vote
1 answer
184 views

Individual Three Phase Potential Transformers vs Three Potential Transformers in one case

If I had to select between Individual Three Phase Potential Transformers vs Three Potential Transformers in one case for a 600V system (which doesn't require many inches of spacing between phases to ...
VMMF's user avatar
  • 399
0 votes
2 answers
4k views

Stepper motor failing. Electrical interference?

Update: This question is already so long, I'm hesitant to add to it but it occurs to me to ask if electrical interference between the stepper motor wires could cause this sort of behavior (motor ...
spring's user avatar
  • 207
0 votes
1 answer
2k views

Electrical noise resets & chattering in relay modules using ESP8266

I am trying to build my own SONOFF like device by using a Wemos D1 mini and associated circuitry. I am facing an issue with electrical noise where whenever switching of the relay causes chattering ...
Vijay's user avatar
  • 51
0 votes
0 answers
340 views

How to reduce spike in Power Supply and GND (SCR + Ignition Coil)

My circuit: Signal coupled in power supply (3.3V) of STM32F103 during spark: Is there any benefit to using this diode (circled in red) or not (without this diode the snubber circuit will start ...
Fabio CRJ's user avatar
-1 votes
1 answer
6k views

Bluetooth Interference with High Pitched Tone

i'm building a portable stereo system and am having some unwanted noise from the bluetooth receiver. the noise is typically a high pitched tone. please see the attachment for my chicken scratch ...
Jake's user avatar
  • 11