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.

Filter by
Sorted by
Tagged with
1
vote
2answers
66 views

Electromagnetic compatibility problem with an hairdryer

I wanted to ask you if you could give me an explanation of this electromagnetic compatibility problem. I connected my (fully working) TV to a certain electrical socket in my house. I have also a ...
0
votes
1answer
51 views

4 layer PCB controller below layer query [closed]

I have designed in 4 layer PCB. My Controller placed on the PCB top side / first layer. 2nd layer full ground plane. 3rd layer Power plane (fill or not? please confirm.) 4th layer ground fill.
0
votes
0answers
63 views

How to read/understand Bode plot of Insertion loss in EMI Filter

I am designing a noise filter with a Target frequency for noise reduction =100KHz and with the help of Murata Noise Filter Designer website. Recommended circuit from Murata with component value is ...
2
votes
2answers
67 views

EMC - conducted emissions - unused wires in cable - puzzling coupling

I am trying to understand the impact of unconnected wires in a cable for EMC conducted emissions tests. My product has a shared unshielded cable for supply and communication (I know it's bad practice....
0
votes
1answer
54 views

Where to connect TVS clamping Diodes

This question just came up during the review of a design. Should the TVS rather be placed before the feedthrough-cap or after? I would place the TVS before the cap (see A in schematic) because TVS ...
1
vote
1answer
189 views

Strange noise at peaks of measured sine waves STM32F103

Please look at this picture: I'm using STM32F103, a popular Blue Pill module. What you can see in the picture are three signals, from bottom: green - AC voltage of 14V RMS, measured with step down ...
0
votes
0answers
15 views

Application circuit G3NA-210B

Simple doubt about EMC directive on page 15. Should I use the varistor, cap and toroidal core on non UTU model? I want it to be compliant with safety directives, but I dont want to interfere with ...
2
votes
1answer
68 views

LTSpice - Problem Wurth filter

I am trying to simulate the 810911001 line filter (Wurth Electronik) on LTSpice which I downloaded on the following link : https://www.we-online.com/catalog/en/WE-CLFS/ I tried to simulate the ...
1
vote
1answer
159 views

Is it better to route Ethernet on the top layer, or to use vias?

I'm making a circuit board with Ethernet (PoE if that makes a difference) coming in through an M12 connector, passing through magnetics and a PHY and going to a micro. I've always heard that there are ...
1
vote
1answer
77 views

How to know if test points can introduce EMC problems

After getting some advices from my PCB manufacturer and from people here, I decided to change the PCB design I'm working on so the PCB could be tested using a bed of nails. To do so, I added test ...
0
votes
2answers
72 views

Parallel power traces with PWM and unwanted EMI

I'm in the process of designing a PCB for an RGB LED light source that will allow me to dim each color channel separately using PWM. To help manage the thermal output of the LEDs I'm trying to use an ...
0
votes
1answer
132 views

Common Mode Noise filtering for Diff Mode Circuit

I have a circuit that has only two pins and there is no earth ground. However, I have to test it for BCI and design a common mode filter with diff mode. Designing diff mode filter is simple but common ...
0
votes
0answers
68 views

Relay contact side protection

Do we need any protection on the contact side of the relay (Ex: form C 240V 3A) if the contact side is not powered by the circuit. if we have to protect, then how(Please provide an example). Also, ...
1
vote
1answer
250 views

Shielded Ethernet Cables in Office Buildings - Ground Loops?

I have a question related to shielding and grounding of ethernet cabling in industrial environments, offices and datacentres. What I assumed as correct so far (please correct me if I’m wrong): In ...
2
votes
4answers
59 views

Solutions to fix LED light RFI/EMI?

Almost every LED light I've tested (hold an AM or shortwave radio antenna nearby) emits RFI or EMI across a vast frequency range. The EM noise comes either from the base of the bulb, or from some box ...
1
vote
1answer
149 views

PWM motor control - weird voltage ringing issue

I'm having some issues with a specific 24V brushed DC motor I'm PWM controlling. I'm seeing some rather nasty voltage spikes and ringing on every PWM on and off cycle. All scope measurements are ...
3
votes
1answer
279 views

Routing strategy - 24-bit RGB display on a 4 layer PCB

I'm routing traces between a microcontroller and a TFT display (24-bit RGB, clock frequency at 18 MHz).The stackup is: L1 - Signal L2 - GND (solid layer) L3 - PWR (solid 3.3V in the region of ...
1
vote
0answers
21 views

Questions about grounding schemes when converting a double-insulated audio amplifier into a power supply for a 90vdc treadmill motor

I was given a free Denon AVR3311 AV receiver (a.k.a. audio amplifier) which I immediately gutted and converted to a bench power supply. I combined the "B+" and "B-" rails into a single, ~130Vdc output,...
0
votes
1answer
39 views

RF shield needed for BLE SoC in PCB design

I´m checking the implications of using BLE in a new design. This design will include in the same PCB a BLE SoC, the specific matching network and an anetnna (still checking if I´m going to use a ...
1
vote
0answers
60 views

Need to branch USB data lines… what to do with unused ends?

I have a USB 2.0 low-speed connection design with an unusual constraint. On the host side the D+ and D- lines have a branch, a requirement of the connector and this cannot be changed. On the device ...
0
votes
2answers
82 views

How to reduce EMI susceptibility for board to board connectors?

I am planing to design an MCU based board. Although I don't need all the GPIO's, SPI's, PWM pins, etc. I like many of them to be connected a card edge connector or board-to-board connector. So, I can ...
0
votes
2answers
35 views

EFT Simulator Duration Time Setting / IEC 61000-4-4 / KeyTek CE 40

I've got an antique EFT simulator, it's a KeyTek CE-40. I'm debugging a device for EFT as per EN 61000-4-4. The manufacturer doesn't provide support for the device anymore and I don't have a product ...
3
votes
2answers
125 views

EMC testing of devices with Ethernet

I've made a board with two Ethernet ports on it and so far when testing it for EMC I've been connecting them together with a single cable. My assumption was that since there are constant keepalive ...
0
votes
1answer
38 views

Does a load reactor eliminate the need for EMC cabling?

The company I work with installs ventilators driven by VFD's. To save on cost of EMC cabling we use load reactors at the VFD outputs. (Other considerations for not using EMC cabling have to do with ...
3
votes
2answers
183 views

How can I fix EMC problem over my PCB?

Here is my PCB drawing that couldn't fix EMC problem. There are peaks at 120-130 MHz at radiated measurement. Are there anyone who have any opinion to fix this? Note: My circuit behave as led driver ...
10
votes
2answers
2k views

Hobby breadboard wiring guidelines to stay within legal RF/EMI limits?

Assume a middle school or home hobby lab with a bunch of breadboards, jumper wires, and 3.3V microcontrollers fast enough to toggle IO at RF frequencies (if not at the fundamental, at lower harmonics ...
0
votes
0answers
47 views

USB Charger Voltage Specification - Transients

Is there a specification for a USB charger that discusses whether voltage transients are acceptable, is if so, under what conditions? Specifically, I know a USB charger needs to have a voltage of 5V +...
0
votes
1answer
59 views

Electroluminescent wire and EMC

I have been thinking about using EL wire in our house as a night light but I am concerned about electromagnetic compatibility and possible adverse effects on the inhabitants (we). You can see these ...
1
vote
1answer
56 views

Decoupling capacitors on opposite side of board when using PCB mount EMI shield

When using a PCB mount EMI shield, can you put decoupling capacitors on the back side of the board? Well of course you can put them there, but will it make the shield essentially useless? Or will ...
0
votes
1answer
97 views

Caseless PC - should I be concerned about incoming EMI

This is a follow-up to this question. I have built a custom PC case that is essentially cardboard. Are the components likely immune to ambient EMI or do they build them under the assumption that a ...
0
votes
1answer
58 views

Syfer (now Knowe) X2Y EMI filter

I struggled to compare the EMI filter needed for 24V to 5V non-isolated BUCK DC/DC (running 300KHz to 500KHz) to ensure it passes CE conformance. I wish to keep switching noise within the DC/DC area ...
0
votes
1answer
286 views

How to design this filter?

I've a full bridge dc-dc converter and I'm trying to understand it. It has 48V input and 400V output with 1600W rating, 30kHz switching frequency. At the input of this SMPS there's a filter ...
0
votes
0answers
86 views

RS485 - Comunication lost during EFT IEC 61000-4-4

I'm having throubles with communication over RS485 in harsh industrial environment. We perform test in EMC lab, acording IEC 61000-4-4 = Fast transient (also known as Burst). We used burst generator ...
0
votes
2answers
120 views

How can I easiest (cheapest) I'm within EMC regulations?

I'm a hobbyist that's currently developing a simple clock and hoping to make it into a small scale sellable product. It's a simple 5V USB clock with a ATTiny84 8MHz clock, a RTC-module and some WS2813 ...
0
votes
2answers
62 views

Very long PCB trace causing microcontroller to wakeup?

I have a design where I'm using an ESP32 as the device's main controller. The system is battery powered, so the ESP is in deep-sleep a lot. It can be woken up with a simple button push (detecting for ...
0
votes
0answers
109 views

Radio static caused by windscreen wipers

I was driving past a radio station transmitter of the radio station I was listening to. I turned on my windscreen wipers, which caused a noticeable static to be emitted through the speakers for the ...
0
votes
0answers
67 views

Experimenting with a Walkie Talkie

This is one weird bizarre thing which I noticed while I was in the electronics lab. I had this Power Supply and a walkie talkie similar to this I have not ventured in RF side yet. The power supply ...
1
vote
1answer
122 views

Purpose/Difficulties of having a common mode choke

This question is related to common mode choke. I know I have asked this question a couple of times in this forum and I have also read related questions and answers. But I am not able to get the total ...
0
votes
3answers
143 views

Is EMC shielding of a grounding wire required?

Consider the following 2 use cases: Fully electric vehicle with 2 different insulated voltage systems: 1 high voltage @1000V DC insulated from chassis and 24VDC system with minus pole (-) at chassis. ...
0
votes
1answer
61 views

Low Frequency EMI

I was wondering if low frequency EMI can occur with PWM or other sub MHz signals. I am aware that harmonics of these signals can generate EMI but I was wondering if the fundamental frequency can ...
0
votes
1answer
158 views

Emi Filter Design with Tracopower isolated power supply in railway application

I'm designing, for a railways application, the power supply circuit on a pcb board that supply 5Vdc starting from a 24Vdc(coming from a not clearly defined source, sure a 24Vdc line). I'm using the ...
0
votes
1answer
46 views

EMC issue on isolator part

I have used two X1 safety capacitors in series with an isolator (ISOW7842DWE). I have fault on EMC test on 64MHz. When I remove the capacitors, the EMC issue is reduced by 6dB. I have used two safety ...
0
votes
0answers
45 views

RF output power too high because of PSU cable

We have a situation where an integrated 868-920MHz RF chip is programmed to output the chip maximum of 14 dBm power. From professional chamber/measurement equipment 16 dBm is measured in the carrier ...
1
vote
0answers
49 views

Voltage spikes caused by stray wire

I recently had a PCB designed which has several analog, digital, and power elements. The board is powered by 24Vdc which is stepped down using an LDO to 3.3V and 5V. These voltages are used to power ...
0
votes
2answers
98 views

EMC issue on 6 layer PCB design [closed]

I have EMC issue and there is spike at 64 MHz on my 6 layer PCB design. I have used many decoupling capacitors and ferrite beads according to the datasheet. Is there any cad tool to measure on which ...
0
votes
2answers
83 views

Proximity of a DC / DC converter and operational amplifier

There is an operational amplifier LM258WYDT, which outputs a signal with a frequency of 1 kHz. It is powered by an TMR1222 isolated DC/DC converter, which produces +12/-12V. For example, the DC/DC ...
2
votes
0answers
33 views

What could potentially affect some specific LoRa frequencies among others and how to mitigate it?

I have started a small LoRaWAN network. I already have setup: 1x LoRaWAN gateway (LAIRD RG186, using EU863-870); 4x T/RH Nodes (Dragino LHT65, same standard); LoRa ...
0
votes
0answers
138 views

Relay Switching MCU Hanging/Reset

I am working on samD21 MCU to control the 16 relays. I am also using a circuit to detect the input AC switch status On/OFF (Connected serially to the relays). This is connected through optocoupler ...
1
vote
1answer
118 views

DC brush motor EMI

What kind of frequency does a DC brush motor generate? There are a few explanations online as to what causes EMI in DC brush motors (commutator sparking for example) and how to reduce it, but no ...
0
votes
0answers
46 views

EMI Filter - DC DC Converter No Differential Mode Filter Outlined

I am currently looking at installing a DC-DC Converter. https://www.xppower.com/Portals/0/pdfs/SF_QSB300.pdf The datasheet outlines a recommended EMI filter as so: My question is as the datasheet ...

1
2
3 4 5
13