Questions tagged [emc]
Electromagnetic compatibility (EMC) is a branch of electronics related to identifying and solving problems caused by electromagnetic interference (EMI) between devices. It encompasses both attempting to prevent unwanted emissions from a device and also ensuring that emissions from another device will not cause spurious operation. EMC depends upon many system-level details; when asking questions, please provide as much information as possible.
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Inductor of twisted pair cable and of a wire
I found two calculators on internet for calculating the self inductance of a wire and an other calculator for calculating the inductance of twisted pair.
Here are the results for the following ...
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Considerations in board layout for different interface speeds
Currently, I'm working on a design that includes four data buses operating at different datarates.
The signals connect various parts of the system to the central FPGA. I have experience in designing ...
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Monitoring system components affected by interference in EMI testing of wired ethernet
I'm conducting Electromagnetic Interference (EMI) testing on Ethernet setups running Windows and Linux. My primary objective is to identify specific system components affected by interference and ...
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How likely can a Bluetooth IC get damaged if the antenna has a wide bandwidth?
I design a device with a Bluetooth low energy chip (DA14863) that sits at different positions on the human body (minimal distance of 0.7mm). Simulation shows that the human body absorbes up to 95% of ...
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How to perform conducted emission simulations
I am currently attempting to design an EMI filter for an AC/DC power supply that is too noisy to pass conducted EMI testing for MIL-STD-461 (115Vrms, 50Hz).
In the lab I have measured the DM and CM ...
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Ground loop with oscilloscope probes
I am trying to better understand how ground loops affect a circuit and why it is important to do not have ground loop on a circuit. So I am trying to look at systems with ground loop to further ...
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Common mode choke placement for good EMC performance
I am interfacing a deserializer with Quectels smart module.
The CSI lines of the deserializer are connected to the CSI lines of smart module.
A common mode choke is placed in between them. The ...
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Do I need to add a filter for an isolated DC-DC converter?
I have purchased three CUI Isolated DC-DC Converters, the models are VHK50W-Q24-S5, VHK150W-Q24-S12 and VFK600-D24-S24. I wonder you could help / guide me to the correct use of them.
Questions:
I saw ...
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Ferrite Topology For Motor PWM
Brushed motors are pretty noisy devices, especially when driven with PWM. There are a number of techniques to reduce the transmitted noise (twisting wires, shielding etc) - one of these is using a ...
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Digital signal routing for EMI/EMC
REMOVE THIS WHEN YOU ANSWER THE QUESTIONS IT ASKS
YOUR DESCRIPTION IS UNCLEAR. PEOPLE MAY NOT UNDERSTAND THE QUESTION PROPERLY AND SO WASTE TIME ANSWERING IT. You talk about transcievers and devices. ...
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Test lab noise floor variance and emission limits
I have recently taken part of noise floor measurements for emission tests from two separate EMC labs, both well known and international companies. The thing that shocked me is the dramatic difference ...
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Connecting secondary ground with primary ground
My system must be made of 2 DC/DC converters and a battery (safe voltage level). I already have a DC/DC converter that I bought on internet. It is the following. It is an isolated DC DC converter. I ...
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What is the purpose of connecting your reference ground plane to earth when doing radiated emissions testing?
In most standards it's required to connect the reference ground plane to earth.
However in a lot of cases the reference ground plane is elevated above the earth by a set height.
If you left the earth ...
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Tight GND plane Pros and Cons
Imagine a typical 2Oz/1Oz, 4 layer PCB with a stack-up, Sig/Pwr, GND, GND, Sig/Pwr. Your typical trace width/space would be 0.2mm/0.2mm, and a prepreg Dk of ~4, ignore the Core. Fastest signal on the ...
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Avoid ground loop for multiboard high-current device
Problem overview
I am designing a multi-board pulser device for ultrasound, and am encountering a conceptual issue when trying to prevent a ground loop in this device. I added a minimal example to ...
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Can the Antenna Factor of a passive antenna be improved by adding a pre-amplifier?
If so what are the main considerations with respect to the noise of the amplifier?
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Reducing EMI from PWM controlled Led segments
I am currently designing a product that has a ring of LEDs with 7 individually dimmable segments.(all together about 40 standard (blue/white)LEDs max 15mA each) the only supply voltage is 3.3v but I ...
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Ethernet MLT-3 signall probing
I am getting radiated emission failure in my system, where the emissions were out of limit (~5 dB) for frequencies 125 MHz, 175 MHz, 225 MHz, 275 MHz, 775 MHz, 825 MHz. This sounds like the odd ...
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Reducing EMI with ground plane
I came across this post on how to reduce EMI in a PCB. From this, I learned that there actually exist two types of current. The first is the conductive current (the current that flows through a ...
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What is the best practice when replacing a ribbon-cable ferrite clamp with chip ferrite beads?
I'm working on EMC testing a product. We have an internal 30 cm ribbon between 2 boards. One has a MCU and LCD, and the other MOSFETs and a 3 A switching regulator.
We determined that a lot of RF is ...
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Common-Mode or Differential-Mode Choke Circuit
This circuit, located at the entrance of our power circuits in the products produced in the company I work for, caught my attention. The design of the circuit was completed a long time ago, and now ...
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Do I need to connect a resistor at the output of an isolated DC-DC converter module?
I am using D050505S-1WR3 in my design for powering an isolated CAN transceiver. The can transceiver is the ISO1042BDWV from TI.
Below is the schematic of the power supply and CAN transceiver.
During ...
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PCB Bottom layer GND pour some portion not connected to GND plane
Below is the bottom layer of a 4 layer PCB.The stack up is SIG-GND-Power-Signal.
You can see that there is a floating ground whose some portion is not connected to GND plane.
I have shown that in red ...
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230 VAC 16 A relay Circuit for Reduced EMI
I am designing a PCB that will needs EMI testing from a laboratory. I have a 230 VAC 16 A relay in PCB. I am not sure will it cause EMI issues while switching between loads or not. If anyone as better ...
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What is the tension member in IEC 61000-6-8:2020 Table 6?
In IEC 61000-6-8:2020 3.1.10, an optical fiber port is defined as port at which an optical fiber is connected to an equipment. In Table 6 – Requirements for conducted emissions, other wires ports, it ...
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CE Compliance: what is the limit of self-declaration for Industrial Control Panel?
We are a system integrator making custom electrical control cabinets. This is our first time on making panels for European customer, and of course they mandated the CE marking.
The control panel they ...
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Why does switching the winding direction on transformer give me a better conducted EMC meassurment?
I am making a charger and I am measuring conducted and radiated EMC.
The circuit is a flyback and the transformer in mention is a sandwich style transformer with 4 windings. Primary windings, ...
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Can I route PWR signals under RFIC?
I am designing an RF amplifier (< 13 GHz) and want to use a board with two layers. However, the RFIC footprint (16-VFQFN Exposed Pad) has RFIN on the left, VDD on top, RFOUT on the right, and VGG ...
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Correct way of optical input EMC protection
I tried to find an answer online, but didn't find anything that would make my doubt go away.
The thing is: when you want to protect any input, that is referenced to ground, you use ground-referenced ...
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What to expect from adjusting the suggested EMI filter and surge protection on a DC/DC power supply's application note. 61000-4-5
I am trying to make the CQB50W12-72S12 120VAC input capable by adding a bridge rectifier into the design that is already called out in the application note (app note and data sheet found here: https://...
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CMTI of a push pull converter
According to this article, a push converter has good immunity against Common Mode transient :
It is said "The flux generated by the current flowing in one primary coil cancels the flux generated ...
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EMC and Control Area Networks [closed]
With radiated EMI tests, do we need to take into account the communication cabling and its influence on EMI?
I can't seem to find one standard that describes how CAN busses should be configured in EMI ...
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Best placement of bridge rectifier to allow DC/DC convertor to become AC/DC convertor. Does this inhibit surge and EMI performance?
I am trying to use the power supply: CQB50W12-72S12 with AC power without degrading the performance of its recommended filter and surge components. 120VAC peak voltage is 169V and I am worried that ...
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EN61000-4-5 Surge protection of PCB power supply
I am trying to better understand how EMC testing is simulated and passed. The datasheet of the CQB50W12-72S12 says it pass level 4 line to earth 4kV; and +- line to line 2kV with just a TVS diode (...
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EMI emission of the classical smartphone charger
I would like to ask you about the significance and quantity of electromagnetic interference (EMI) that produce classical mobile phone charger (transformer).
I would like to install one in a turntable ...
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Declaration of conformity to EMC Directive
We need to declare CE compliance of a system consisting of pumps, valves, sensors and control cabinets. I am dealing with the EMC element of the certification.
I have collected the manufacturer's ...
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MPQ4470-AEC1 Layout guideline clarification
I am using MPQ4470-AEC1 in my design. In the datasheet page no 18 contains the layout guidelines.
I have some questions about guideline no:2 and no:3 .Those guidelines are given below.
Place input ...
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PCB inside metal chassis. Is chassis ground required?
I have a project that has a PCB housed in a metal enclosure. The PCB is powered by a USB-C connector. Power input is 20 V DC @ 4 A max. Power is sourced from an isolated AC/DC wall wart adapter. The ...
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Is plastic package for oscillator bad for EMC?
I usually use oscillators with metal/ceramic package, but I am inherited with a design that uses plastic package. Now it failed radiated emission that aligns with its harmonics. I understand many ...
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EMC filter for two wire flyback SMPS
I am designing an EMC filter of a two wire (no earth connection) flyback SMPS.
In the EMC filter, AC line usually has two Y capacitors after common mode choke connecting earth (PE). Since this SMPS ...
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VFD interference with microcontroller
I’m doing a project that requires the control of a VFD (variable frequency drive) that powers a motor by using a microcontroller to send the signals.
When the VFD is powering the motor, there is a lot ...
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Differential Mode EMI Filter Design for DC Power Input Noises
https://www.murata.com/en-us/products/productdata/8796777775134/ENFH0008.pdf
https://www.digikey.com/en/products/detail/murata-electronics/BNX022-01L/1825573
Hi everyone, I try to understand this ...
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Load switch unused pin: floating or ground through a resistor
I am using TPS1HA08BQPWPRQ1 in my design. This is for automotive application.
Regarding unused pins TI gave the following recommendations.
May I know which one will be better: floating or connecting ...
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What is the cause of Arduino glitching in this DIY soldering station?
I was following this (Spanish/Spanglish warning) tutorial to create a DIY soldering station. I created the schematic, PCB and ordered the parts to assembly, used a cheapo 5 V and 24 V AC-DC power ...
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Coupling Inductor
I read a paper about EMI in switching power supply from CPES.
This is the paper name "Common Mode EMI Noise Reduction Techniques in Switch Mode Power Supplies"
In the context I am confused ...
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Review Request Schematic - LISN Design
I need help with designing an LISN (Line Impedance Stabilization Network) for pre-compliance testing. This is my first big PCB project. It is not for sale, it will only be used at my job for testing ...
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USB peripheral: connecting USB shield to GND?
I have read through many recommendations articles, and many StackExchange questions, but haven't come up with any clear understanding as there are many conflicting information out there. The simple ...
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Predicting EMI/EMC Issues from Microcontroller AC Spec Rise time fall time
In one of his video Rick Hartley says signals with fast rise time can cause EMI/EMC issues.
I am using FS32K148UJT0VLQT in my design. In my board this controller is working at 5 V supply.
Below image ...
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ESP and a metal cover (but not on every devboad) cover under which it hides
This is regarding the metal cover on the ESP devboards, which covers, among others, the ESP itself, flash memory, etc.:
This topic has been discussed here before, and the reason for this cover is
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Layout guidelines for TCAN1043DRQ1
I am using TCAN1043DRQ1 in my design.
May I know what are the layout guidelines I need to follow.
I checked the datasheet it. It does not say anything about layout guidelines. It tells more about ...
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