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.
1,160 questions
-1 votes
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EMC requirements for cable trays with shielded cables only
We have installations with several powerful motors and transformers (up to 2 MW) which are driven by VFDs. Due to some geometric constraints the VFDs can't be placed near the motors. To minimize ...
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2 votes
1 answer
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PWM controlled load: EMI best practices
I am driving passive LEDs (24 V, 1 A) through two transistors activated by a ~10 kHz PWM signal. The power goes through a shielded cable from the PCB to the LED module. My wider setup should be CE-...
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0 votes
1 answer
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USB CDC on STM32F4 disconnects when controlling 3-phase motor; STM32 runs, PC can’t detect USB
Here is my setup STM32F401CCU6 WeAct Blackpill, which controls A 3.3V-24V Optocoupler, which controls A Siemens 3-phase contactor to switch a 400VAC induction motor, with flyback diode on the ...
0 votes
1 answer
68 views
LVDS Line EMC EMI protection
I would like to ask you about EMC and EMI improvements for LVDS lines. Let me describe the structure I am going to set up. The cards on a backplane will communicate with a central processor card point-...
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3 votes
2 answers
171 views
Routing techniques for FFC breakout
I am trying to breakout the pins from an FFC receptacle that connects to a 7 inch TFT LCD touch screen to header pins. This is part of a board that I'm designing which is meant to create a working ...
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4 votes
1 answer
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Connection between frame and GND on a robotic system
I am developing a mobile robot that has a battery with a nominal voltage of 24 VDC. According to a relevant norm, there shall be no electrical connection to the frame of the robot, though there are ...
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2 votes
0 answers
63 views
EMC best practices for Eth lines
I am trying to understand and pass CISPR 32 / 35 for a unit I am making, I have the general idea mostly down but I would like clarity on the best practices for attaching my ETH isolation transformer (...
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1 vote
0 answers
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2kV 8/20us surge testing issue with TDK-Lambda CCG30-24-12S DC-DC converter
I am evaluating a TDK-Lambda CCG30-24-12S isolated DC-DC module and have created an evaluation PCB based on the datasheet test circuit. When trying in house surge testing with a Lisun SG61000-5SB the ...
3 votes
2 answers
494 views
Bead vs choke characteristics
I seem to have confused the concepts of beads and chokes. Bead: Operates as an R due to LC resonance, causing heat loss and acting as a filter (hysteresis loss/eddy current loss). Choke: Generates ...
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0 votes
1 answer
107 views
Ferrite core vs nanocrystalline core
I understand that nanocrystalline cores have slightly higher permeability and lower losses than ferrite cores. In a cm-mode choke, I understand the EMI rejection principle as follows: Rapid change in ...
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1 vote
0 answers
80 views
Analog Circuit Decoupling Cap Layout
Most EMI decoupling capacitor questions on this site pertain to bypassing digital ICs with fast rise times and specific routing constraints. In the context of no such ICs or routing constraints ...
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0 votes
1 answer
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Metal shield near field far field
I'm researching metal shielding. Near-field, electric/magnetic fields: absorption (skin effect) Far-field, working waves, plane waves: reflection (impedance work) This is what I understand. However, ...
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0 votes
1 answer
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What is the relationship between attenuation and impedance with these common mode chokes (CMC)?
I have a question regarding 2 CMCs. We want to filter some common mode noise from 150 kHz to roughly 700 kHz. Trying to resolve some AC mains conducted emissions measurements. The two CMC we ordered ...
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1 vote
1 answer
89 views
Mounting Hole Grounding Strategy for High-Current PCB With AC Earth and DC Ground
I'm working on my first PCB that integrates both an AC source (with protective earth/PE) and a DC ground plane (GND). This board is designed for high current (up to 10A), so good layout and grounding ...
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1 vote
2 answers
103 views
EMC Emissions and Immunity Relationship
Currently working on a Radiated Immunity problem on one of our products. The product falls over at multiple different frequencies when exposed to 10V/m field. Failures occur at various frequencies ...
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