Questions tagged [emi-filtering]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
4 votes
1 answer
351 views

What is meant by the statement "Local bypass capacitors are needed to control EMC coupling with heat sink"?

During a talk, not sure what the speaker meant by the statement " We need to add local bypass caps to control EMC coupling with heat sink" He was referring to the MOSFETs in synchronous ...
user avatar
  • 2,051
2 votes
3 answers
232 views

What is the core material being used in CMC (Common mode choke) and DMC (Differential mode choke)?

The core symbol in below diagram indicates that it is an iron core material but Iam not sure whether it is correct. I see the same representation in many other circuit schematics as well. Below ref ...
user avatar
  • 2,051
2 votes
1 answer
122 views

Why are differential mode chokes (inductors) not generally coupled?

I understand there are both coupled and un-coupled versions of differential mode chokes as shown below. Which one is better? I see most of the designs having un-coupled version. What is the reason? ...
user avatar
  • 2,051
3 votes
3 answers
714 views

How can failure of Class Y capacitors lead to electric shock?

This article mentions "Due to the fact that equipment cases are usually grounded, Y caps require higher safety to avoid risks of electrical shocks to users" How can an equipment with ...
user avatar
  • 2,051
0 votes
0 answers
62 views

What is the purpose of this pad

What is the purpose of this pad, located between the PCB in the picture and a wifi card? It is completely enclosed in Kapton tape and there are no exposed grounds on the PCB below, on the bottom of ...
user avatar
  • 21
2 votes
2 answers
107 views

Power supply noise reduction

I am new to electrical Engineering and would like to know wich noise reduction filter ist better for use in audio equipment. Some decalcifications: VBUS --> 5V from usb-port GND --> Ground from ...
user avatar
0 votes
1 answer
35 views

Finding DC saturation behavior of clamp ferrites

While some chip ferrite datasheets specify maximum current and DC saturation behavior, it seems like many clamp ferrites omit both maximum current specification (which arguably is less critical) but ...
user avatar
-1 votes
0 answers
55 views

Automotive Power Supply Input Filtering Design

i'm looking for some critique and pointers for the power supply and filtering design that I have come up with so far. This is a personal project that I have spent a couple of weeks on in my free time, ...
user avatar
0 votes
2 answers
52 views

EMI analysis for low power low voltage AC/DC

I've designed an 80W 220V-IN 400V-OUT PFC Boost converter in order to analyze its conductive EMI and design the proper active EMI filter for it. but as this is my first implementation project, working ...
user avatar
  • 457
0 votes
0 answers
45 views

Can I use MKT capacitor instead of MKP in the following topology?

The following topology is a boost PFC designed by STMicroelectronics. The input capacitor (C1) is an MKP one. Can I use an MKT (fig2) or polyester (fig3) capacitor instead of that?
user avatar
  • 457
0 votes
0 answers
26 views

Current in inductors of emi filter

I am currently working on an EMI filter for a led driver (constant current). Here you can find the according schematic: My question now is, which (if any) current is going through the inductors/have ...
user avatar
  • 11
0 votes
0 answers
46 views

EMI Filter - current in inductors / part selection

I want to use a NLDD-1400H LED Driver as constant current source with 1.4A ouput. On the last page of the datasheet there are information about an EMI Filter, I want to use. Here is the schematic: ...
user avatar
  • 11
2 votes
1 answer
124 views

Question regarding connecting LISN to a three phase PFC

I am trying to connect a Line Impedance Stabilisation Network (LISN) to a three-phase PFC rectifier simulation model as I want to simulate the common-mode and differential mode EMI. Most references on ...
user avatar
1 vote
1 answer
55 views

Break peak inrush current

I want to renew a 30 Year old line-filter 230V AC for an electronic device. At the end of the filter is a 230V transformer with 9 secondary outlets: 5.8V, 51.4V, 16V, 13.3V, 9V, 9.8V, 18V, 80V, 100V. ...
user avatar
1 vote
4 answers
951 views

How to design EMI filter if you don't have the actual physical circuit ready?

I have a designed a battery charger in simulink and for the sake of completeness and as a learning experience, I would like to explore EMI filtering and design one for it (as a simulation model). I ...
user avatar
1 vote
0 answers
42 views

DC main power fluctuation filter

I want to design a filter at the input of sensor with DC power, this DC power is sourced to this sensor (analog microphone with preamp and 20-20kHz bw and it will be sampled in 12bit) and I have total ...
user avatar
3 votes
2 answers
60 views

EMI filter and bypass capacitors for Mornsun DC-DC

The datasheet for Mornsun K7805MT-500R4 DC-DC module has the usual required capacitors in typical application circuit: And just as pretty much any other datasheet they provide additional schematics ...
user avatar
  • 10.3k
0 votes
0 answers
62 views

Inductor selection for differential filtering

I'm designing a line filter (230Vrms) and I am not sure how to choose the differential filtering inductors. I have calculated/simulated that I need 33µH inductors, but I am unsure how to actually ...
user avatar
  • 65
0 votes
2 answers
52 views

Conducted EMI on power lines filter

I've been looking around for answers for a while now and I haven't been able to find anything. Does anyone know how EMI filters are rated? The only specs I have been seeing use an attenuation curve or ...
user avatar
0 votes
0 answers
82 views

Is this filter burnt and the capacitor damaged?

I'm repairing a Ring Chime PCB and have noticed what looks to be a burnt ceramic filter, and a capacitor next to it which is shorted. The white rectangular component is labelled FL1 which makes me ...
user avatar
0 votes
1 answer
52 views

How do you build a spurious emissions test rig?

Naively, it seems like you could test for spurious emissions by: Placing the device-under-test (DUT) in a grounded metal box with a broadband antenna inside. Hook the antenna's coax cable to the S21 ...
user avatar
  • 774
10 votes
2 answers
237 views

Is a balancing diode really necessary for the Balanced Boost converter?

Please pardon all of the information that precedes the question -- I didn't want you to actually have to go read the paper itself. This question is in two parts, but they are really equivalent, so it'...
user avatar
0 votes
1 answer
63 views

GaN Power transitor said to "reduce EMI"

I have no experience in GaN, I am currently discovering the subject and I was studying a design from Infineon and I found on a GaN power transistor the following benefits: Here is the datasheet: ...
user avatar
  • 1,226
0 votes
0 answers
80 views

How to lessen emission of an enclosure box from I/O ports?

I am designing an enclosure box which will contain motor controllers(TB6600), microcontroller(ESP32 and Arduino Mega) and a 12 V power supply. I have not decided which material will enclose this. My ...
user avatar
  • 73
0 votes
1 answer
68 views

Running and grounding paired shielded cable thru a connector

I need to run two logic signals around a vehicle, so for good measure, regardless if its overkill or not, I want to use a shielded single pair wire for that job. At one point it should be crimped to ...
user avatar
  • 35
2 votes
3 answers
147 views

X2 polypropylene capacitor for DC smoothing after AC rectification

Can a X2 polypropylene film capacitor be used for dc smoothing at the output of a bridge rectifier? I want to use this capacitor at the input of a power factor correction circuit with a switching ...
user avatar
  • 77
-1 votes
1 answer
132 views

Common mode choke and grounding

How would you connect the cable shielding, metal enclosures and power ground on following system: Since I had problems with noise before I wanted to add filtering on power input for "my PCB"...
user avatar
  • 55
0 votes
1 answer
64 views

Leakage current 2-pin usb-c charger [closed]

since I began using a 2-prong usb-c charger, i have noticed a vibrating sensation when moving my hand over the metal body of my laptop. If i ground myself, the vibration gets stronger. If I use the ...
user avatar
1 vote
1 answer
91 views

Burned component on GIGABYTE RTX 2080 GAMING OC 8G

I have purchased an RTX 2080 which contains a scorched component. I have carefully removed it with a heat station. The card is not short and it works, but it is seen with artifacts. As I found on the ...
user avatar
7 votes
2 answers
2k views

Is it a bad practice to use capacitors to GND to prevent long traces from ringing?

Suppose, I have a long trace (e.g. 30 cm) that is driven from one end and that is carrying a DC or LF voltage (e.g. audio signal or power trace). The other end of the trace is high impedance compared ...
user avatar
  • 10.2k
1 vote
2 answers
50 views

Brushed Motor with Wires - Where to put BEMF diode (EMI)?

I'm designing a system that drives brushed motors with PWM, where the motor and the PCB with the drive circuitry is separated by wires. Thinking about the EMI situation, would it be better to put the ...
user avatar
  • 4,729
0 votes
0 answers
58 views

Approach to determine EMI frequencies in another factory

We produce AC-powered devices that connect to PC via USB. One of which was recently shipped to a factory (which is located in another country) in an environment with high enough EMI to make our device ...
user avatar
3 votes
2 answers
690 views

How to design an EMI Filter for AC/DC PSU

I am designing a single phase MIL-STD-461 AC/DC PSU. I have the following requirements to the PSU: It needs to operate with an input voltage from 100Vrms up to 310Vrms. Operating frequency 45-65 Hz ...
user avatar
  • 65
1 vote
1 answer
73 views

Does the negative voltage regulator emit noise into ground

I am designing an inverting voltage regulator using a LT3758 controller to generate -15 V from a 12 V / 5 V input. This is a non-isolated regulator. My biggest concern implementing the design is if ...
user avatar
  • 137
0 votes
1 answer
145 views

What happen when we parallel or series ferrite bead?

If I use ferrite with capacitor as pi network. What happen when I series or parallel the ferrite bead? Which one reject emi better? I known the ferrite bead is not inductance. It act like resistor at ...
user avatar
  • 937
1 vote
2 answers
114 views

Connection of Cx capacitors to neutral in 3-Phase EMI filter

I'm working with a circuit which uses a common schematic for EMI filtering. I simulated the schematic and I added a 200 kHz AC signal to the main 50 Hz line, to model the differential mode noise. In ...
user avatar
  • 166
1 vote
0 answers
54 views

Is this crystal layout OK?

I have a 2 layer board where I have a crystal running at (16.3840 MHz 18 pF). This crystal is used in a component that has internal caps. Does this layout look OK? Or should change anything? On bottom ...
user avatar
1 vote
2 answers
150 views

Will ferrite cores reduce the surge on the 5V line?

I think my ATMEGA AVR MCU is malfunctioning due to 5 VDC line surge. The MCU is installed in a factory and the power line is very noisy. I captured the 5VDC line. There were high frequency (10 MHz) 13 ...
user avatar
1 vote
0 answers
62 views

Will using this mains EMI filter exceed maximum earth leakage when used together with an AC/DC converter

For an industrial piece of equipment with AC power inlet, I want to use this internal AC/DC converter with a given maximum earth leakage current of 2 mA at 250VAC. Now it was suggested to also use a ...
user avatar
  • 10.2k
5 votes
6 answers
1k views

Are anodized fan filters efficient at blocking EMI?

I was looking for metallic fan grills to close a large fan aperture for EMC and found many had a non-conductive finish, e.g. this one claims to have an anodized finish. Doesn't that make them ...
user avatar
  • 10.2k
2 votes
1 answer
142 views

What is the purpose / function of these bypass capacitors in this Isolated Supply EMC Filtering circuit?

I found this EMC Filtering circuit in the datasheet of the RFB-0505S DC-DC Isolated voltage regulator. What is the purpose of C2 (1nF) and C3 (2.2nF)? I don't understand why they are suggested. Is C3 ...
user avatar
  • 333
0 votes
1 answer
62 views

Obtaining EMC measurment equipment

I am an electronics engineering graduate who works on developing the electronics for an EV charger. We are now in the process of slowly getting ready to get the product certified, which includes EMC ...
user avatar
0 votes
3 answers
93 views

Functional ground alternatives in a Class II equipment

Usually we build Class I equipment, i.e. with a ground lead. For EMC purposes we use an input filter (commercially bought). For reference a typical filter is made in this way (source electronics ...
user avatar
0 votes
2 answers
89 views

Split core vs. ring ferrite

I have an Arduino clone with L298P motor driver, which drives a linear actuator with a brushed DC motor and a built-in end of stroke mechanical switches and diodes. Motor runs at about 12V/2A DC, on/...
user avatar
0 votes
0 answers
56 views

Controlling motor EMI - more ferrite turns or shorter cables?

In wiring up a small robot, powered by two BLDC motors (of the "hoverboard" variety), I was going to shorten the leads a bit, and wrap them one turn around a soft-core ferrite for EMI ...
user avatar
1 vote
0 answers
136 views

Can an air core inductor cause a buck converter to malfunction because of EMI?

I am trying to build a buck converter circuit using the LM2596T. While reading its datasheet, it came to my attention that EMI is a potential problem one should not ignore while designing a buck ...
user avatar
  • 553
1 vote
2 answers
136 views

Safety Capacitors; Is it OK to fit an X1 in place of an X2?

I have a PCB which has a 0.010uF X2 safety capacitor fitted. It seems the exact part is now obsolete. Would it be acceptable to replace this part with a 0.010uF X1 safety capacitor? I believe a ...
user avatar
0 votes
0 answers
81 views

How to decide input filter specifications for linear power supply design

I am newbie trying to design a precision linear power supply and I have already chose a transformer which will meet my output requirements. Now, I am not sure how to figure out what parts should I use ...
user avatar
1 vote
2 answers
73 views

Where should I put an EMI filter on a barebones power supply for audio filtering?

I've an audio amplifier that was built from spares from an old kit from 19-something. The power supply for this amplifier is the simplest it could possibly be, consisting of a transformer, bridge ...
user avatar
1 vote
1 answer
283 views

Pi-Filter vs T-Filter for Power Distribution Filtering

When not using power planes, in order to prevent >100 MHz noise from travelling excessively around the board via the power distribution network, one can place filters just outside the decoupling ...
user avatar
  • 10.2k

1
2 3 4 5 6