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 ...

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47 views

Will EMI strongly affect my sensor reading

I'm using an Arduino to read analog values from my sensor running at 5V using a voltage divider. The sensor contains a force resistive sheet where the resistance of the sheet decreases as force is ...
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2answers
41 views

How electronic device affected by electromagnetic interference? [on hold]

I want to know how electronic device affected by electromagnetic interference? For example: Touchscreen device scanning as 190Hz, when noise source around (such as power supply) generate 190Hz noise ...
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1answer
31 views

Alternative Gigabit Ethernet Connector - considerations for impedance, signal integrity, and EMC considerations?

I have a design that does not have enough vertical clearance for a standard RJ45 socket. I'm hoping to use a connector like this one from Molex. I will use Cat5e cable when building my cable with the ...
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1answer
23 views

WIre length in Conducted emission test

What should be the Minimum or maximum input power cable length can be used in Conducted emission test. Length from EUT(DUT) to LISN. What if my product come with input cable length out of MAX limit. ...
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2answers
29 views

Transceiver and RF Emissions (Unintentional)

My question is simply what is RF emissions (unintentional) and how does it relate to a device (such as a smart phone) which contains a transceiver or transmitter (baseband IC) ? Which part of a RF ...
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0answers
24 views

Change in EMI receiver Reading

Good morning all I run a Conducted Emission test on ousside EMI lab (15 Dec 2015) on my product at the result were on below graph PIC 1 (with Ambient graph PIC 2). In each graph there are two traces ...
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1answer
44 views

Expanded standard deviation in logarithmic scale [closed]

Hello and good day to all. Referring to picture attached I have a question. . I am working on different measurements and trying to find the mean and standard deviation values of these ...
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2answers
47 views

12V vs 5V servo

I am looking to actuate a throttle on an internal combustion engine. I am using a 5V servo driven by an Arduino Mega2560 at the moment. The throttle is very close to the engines alternator and there ...
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2answers
63 views

Avoid EMI in power circuit controled by MCUs

This is a toy project just for fun. As anybody knows, if I want to control a lamp by a simple switch, the circuit is as follows: However, I want to change the circuit so I can control a lamp with ...
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50 views

Calculating mean and standard deviation of Power values

My question is related to measurements in communication field. I have done some measurements using spectrum analyzer. I did repeative measurements and got 10 values in dBuV/m. Now I want to calculate ...
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3answers
175 views

EMC testing vs. EMI testing

What is the difference between EMC testing (Electromagnetic compatibility) and EMI testing (Electromagnetic interference)
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1answer
122 views

Are these EMI noises?

I have always heard about EMI noises but have not really meet them or measured them. Our system composes a MCU running at 168MHz and a 16-bit DAC which is supposed to provide high-precision voltages ...
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0answers
36 views

Image current and return current

I find I'm a little confused about "image current" and "return current" in PCB/EMI/EMC design. Are they equivalent? Many docs use this model when talking return current Exactly, I will treat the ...
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2answers
70 views

Ribbon Cable Noise Susceptibility

As part of a product upgrade we are looking at replacing looms of wires bound together by cable ties or spiral wrap with ribbon cable. We are doing this to try and cut cost and assembly times. We are ...
1
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2answers
135 views

Signal and power integrity - 4 layer board

Let's assume that we need to design Mixed signal PCB with 2 fast integrated circuits(tr_min = 1ns) operating at different voltage levels(3.3V and 4V). There are however other voltage levels on the ...
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0answers
24 views

Electric Vehicle Temperature Monitoring

I'm looking to implement a system to monitor the cell temperatures of about 80 cells in a 240-cell battery pack for an electric vehicle (yes, at least 80 cells must be monitored). I'm looking for a ...
3
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3answers
127 views

What is the thought process for specifying an EMI bypass cap on line transformer secondary?

Update It turns out I had mistakenly interpreted the role of the capacitor in question here as an EMI filter for line noise. It looks like a capacitor in that position actually serves as a snubber ...
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0answers
46 views

Is 'RFI' a term in active usage, or is it all 'EMI' now?

I'm studying capacitors in some detail just now, and one of their typical uses, of course, is to bypass high frequency interference at sensitive circuit inputs. I want to get my terms straight, and ...
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2answers
53 views

Buck regulator frequency

I am trying to use a buck regulator. Usually I make it use at its Max frequency and then just use it. But now, we want to go for Emi and emc certification. I am hence told that this switching (a few ...
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1answer
32 views

USB 3.0 LC circuit on shield

I am designing a circuit with USB 3.0, and looking at the reference design from Cypress in the link below. http://www.cypress.com/file/133836 I see on page 47., that the USB connector shield is ...
6
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1answer
86 views

Polarity of USB common mode choke

Can I reversely route the data polarity to USB common mode filter below? Namely, connect USB trace D+ to the filter pin D- to simplify layout. ...
1
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1answer
54 views

Switch-mode power supply and EMI on input power line filtering

I'm trying to reduce some switching noise I'm seeing (using LISN & Spectrum Analyzer) on my input power cable. My SMPS operates at 1.2MHz. I have room on the PCB and I'd like to place a SMT common ...
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1answer
43 views

Direction of E1 and E2 in phasor diagram of transformer

The phasor diagram of transformer is a bit confusing. Is E1 and E2 have same direction? Different books mention it differently. Please clarify!!
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0answers
41 views

EMC shielded box with transparent window?

Is there such a thing? I would like to put my board in a box to isolate it from radiated emissions externally and also limit emissions from the board to the outside. I would also like a transparent ...
0
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1answer
17 views

redundancy checks and protection on monolithic and MMICs

I am using the ISL8026A chip for voltage regulation from 5 to 3.3V. The datasheet is - datasheet. Now, this is merely an example circuit. Now, I would like to design a power supply for a hi ...
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2answers
43 views

EMC Filter and Vintage Electronics

Does anyone have any opinions about using an EMC Filter to protect vintage electronics? I'm referring to very sensitive jukeboxes, pinball machines and this kind of stuff. I have some machines that ...
2
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1answer
66 views

Converting a three-wire system's “EMC filtering configuration” to a two-wire one

I'm designing a board which has -48V input. For the power module, I'm considering using KSTW010A0A Barracuda from GE(DOSA compliant 1/16 brick, Isolated DC-DC Converter) In the datasheet, there is ...
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0answers
37 views

EMI RFI housing / protection. capacitive touch

Can i create a effective capacitive touch(hover) button? Since the first day (playing with mcu's) i was impressed about the capacitive touch lib. The first time everything worked perfectly i wanted ...
3
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1answer
75 views

Conducted Emission Fail at High Frequency

Good Morning All We run Conduction emission Test on Lab with the Line filter and without the line filter. Product was 230V 16A welding Power supply. Below are the graph with line filter and without ...
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0answers
28 views

Latch-up and ESD protection for power supply and RS422

I am designing a power supply board that has switching regulator and 4 LDOs. Now, I understand that layout details or practices that will help reduce switching noise from corrupting the ground and so ...
0
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1answer
55 views

EMI protection for unused pins

I am designing a board that has 2 DB9 plugs/connectors. They are used to supply power(Vcc and GND) and data signals respectively. Now, I wont be using all the pins in the DB9. Some will be left ...
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0answers
36 views

EMC Line Filter AND capacitors in main input line

Good morning everyone, The picture below shows the incoming line of a 3-phase 480V circuit that has been modified to satisfy CE standards. It shows the AC line going into an EMC line filter AND tied ...
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1answer
58 views

Do the test operator must hold an antena during the EMC immunity test?

We are doing EMC test the Capacitance sensing Touch panel, pursues immunity issues versus 28MHz noise. We do it in 2 methods: (1) The operator is holding an antenna(which generated 28MHz noise), and ...
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4answers
2k views

Why is it good to slow down digital lines with resistors?

I've heard that sometimes it is recommended to "slow down" a digital line by putting a resistor on it, let's say a 100 ohm resistor between the output of one chip and the input of another chip ...
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2answers
58 views

Bluetooth bothered from the next house … plausible? Solutions? [closed]

I have two computer sitting in a room at one end of my house. I typically connect a bluetooth trackpad to each, and a bluetooth audio box to one. Every so often, bluetooth communications are ...
4
votes
3answers
238 views

MCU - What's going to happen if I put a PWM output pin right next to a bunch of ADC input pins?

I'm currently considering a MCU-driven circuit that will do a variety of things, including drive some BLDC motors and do some analog sensing (of position sensors, temperatures and the like). The ...
2
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1answer
62 views

How to combining EMI capacitor and ferrite bead change filter characteristics

Suppose I want to suppress the noise at around 100Mhz on a signal line. I can do that using a EMI filter capacitor or a ferrite bead. The frequency characteristics for both show suppression of noise ...
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1answer
42 views

How to Select Near field probe

Please guide me select best suitable Near filed probe for my application out of these two. Which will help to troubleshoot the EMI problem. My Product Need to be compliance in range 150Khz -30Mhz for ...
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0answers
92 views

Switching power supply layout review

In a previous question where a SMPS based on an LM5118 was presented, some aspects of the layout were pointed out as being problematic. I've taken another look at the layout of that section of the ...
0
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3answers
66 views

RE Suppression method

I am working on a Single phase Welding machine with a input voltage of 230V and Current of 20A and output ( 100 A and 24 V). Now we are supposed to pass it CE certification, as per standard EN ...
2
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1answer
71 views

EMP Protection of Ethernet Lines

I'm currently working on protecting 1000Base-T Ethernet lines from EMP using filter connectors such as described on page A-7 of this doc: ...
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0answers
27 views

Dammped osillatory protection device

In our design we have 12V EMI EMC filter and RJ45 interface. we have placed common and differential mode MOVs, common mode choke and series ferrites for 12V EMI EMC filer circuit the EMI EMC filter ...
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0answers
81 views

How to shield an isolated battery powered system?

I'm currently in the process of "designing" (selecting) a DC-DC Converter solution for a battery powered widget that will operate in the desert. It has to comply with various aspects of ...
1
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2answers
190 views

How to shield multiple flat (ribbon) cables properly?

I have a situation where I need to connect 10 flat cables (20 way, 0.625mm pitch) to special PCI-E card in my computer. They go from PCI-E card on back to drive bays in front of computer case. Those ...
0
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1answer
49 views

Walk-in EMC testing a Bluetooth speaker

I'm hoping to see if my Bluetooth speaker could pass FCC Part 15. No certification is needed at this point - just to purely see if it'd pass when it becomes ready for certification. I believe this is ...
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1answer
31 views

Output capacitance of H-Bridge IC (DRV8432DKD) for snubber design

all. I have implemented a hydraulic pump driver circuit using a DRV8432DKD (36-HSSOP package). I provided pads for an RC snubber on my PCB, but I am having some trouble coming up with the values for ...
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0answers
91 views

Will the following circuit cause EMI-problems?

I'm trying to get a feel for which circuits will have EMI-problems and which won't. To make things a bit more concrete, I've designed a super-simple LED-blinking circuit using the PIC16F1788 ...
0
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3answers
73 views

Via fences or pickets important parameters for design

What is more important for EMI shielding effectiveness with respect to guard traces and via fences, the width of the copper trace that circles around the area or the distance between the vias to ...
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0answers
40 views

How can I improve conducted emission caused by a bad primary electrolytic capacitor?

I recently got the job to find out how to pass conducted EMI tests with a bad electrolytic capacitor after the rectifier in a power supply. The background is of course, that the new type is cheaper ...
4
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2answers
115 views

Quasi-peak detector

This is the circuit of a quasi-peak detector: simulate this circuit – Schematic created using CircuitLab where \$ V_{\text{sig}}\$ is the input signal. When the diode is open-circuited, ...