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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Why is it bad to have unconnected metal areas around PCBs/enclosures for EMI?
I've heard that it is generally bad to have unconnected metal around PCBs due to both safety reasons of charge buildup, but also EMI in the sense that these metal pieces can act as antennas and re ...
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Visualizing 2 Layer PCB Return Currents
Hobbyist moving a manhattan-style prototype of an analog FM radio to a PCB for ease of assembly and access to SMT parts. I have attempted a 2 layer FR4 board with a 1.6mm thickness, as I feel that ...
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Recertify against EMC (automotive E-Mark) due to software changes
There is a digital output control module with a CAN interface that I will be working on. Its already certified against EMC, e-mark (UNECE 10).
As the previous contractor will no longer support the ...
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Telecom Lines Conducted emissions noise travel
I am seeking an explanation of how conducted emissions on telecom lines are measured.
The frequencies of interest are at 150kHz to roughly 850kHz.
The size of the unit is 30cm by 30cm by 15cm. The ...
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Does LISN eliminate differential mode noise?
Do I understand correctly that this LISN circuit doesn't eliminate differential mode noise? And when I get a spectrum, there are two parts of noise: differential mode (DM) and common mode (CM)?
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LDO vs voltage reference when input signal is noisy
I am designing an active EMI-filter (AEF) with an op amp (LTC6227). The AEF suppresses noise from a DC/DC converter. Ther op amp requires a supply voltage of 9V and a reference voltage of 4.5V at the ...
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GND plane between tracks or tracks closer enough to remove the GND tracks
I am working in a design with many signals, no high speed signals, just some switches signals and encoders tracks. However I had problems with the ground uniformity sometime ago, therefore I would ...
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Telecom Lines Conducted emissions [closed]
We have rented a Telecom line ISN to conduct some in-house pre-compliance testing. The test setup closely follows the CISPR32 standard. We encountered issues with conducted emissions in the lab, which ...
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Ground plane for SMPS EMI-Filter?
I am designing a board including various switch mode power supplies, e.g. Buck, boost, and so on. The application notes recommend using split ground planes for power and analog parts, however after ...
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Why is my encoder showing abnormal spikes on the oscilloscope readings? Any suggestions on what might be causing it?
So to summarize, I have these winch drives that I've put together. One of them went berserk during testing and now I'm diagnosing the problem. I have attached an oscilloscope to where the KEB servo ...
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EMI/EMC: Connecting PCB mounting holes to chassis in multi-board system
I am working on a system which has a metal chassis connected to the earth. The system gets power from a dedicated PSU. The power lines of the PSU (VCC_PSU / GND_PSU) are fed into a master PCB and ...
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Is there any issue when mixing low frequency power with high frequency digital in a single board? [closed]
Summary
In a board is it okay to just join low frequency power(>10 Hz, 1-15 A, 24 V) with “high” frequencies(~100-480 MHz), being supplied by “different” power supplies but referenced with the same ...
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What differences in terms of fields does a grounded metal and an unconnected metal object have
I previously asked a question regarding absorption and reflections of waves to metal. But id like to know the differences that say a PCB metal pour that is connected to a signals return path, and a ...
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Choosing Y-capacitor value for isolated DC-DC
In an isolated DC-DC converter datasheet (link), the Y-capacitor recommended is 270 pF. How is this value arrived at? And would the intended use of the Y-cap be achieved if a higher value like 1nF is ...
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How to connect heaters and RTD sensors from an EMC perspective
I have a PCB that drives an external system with simple resistance heaters and Resistance Temperature Detector (RTD) sensors for temperature readings placed close to them. The PCB includes a typical ...
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