Questions tagged [emi-filtering]

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34 views

Good solution for TPS54202 input filter design?

I trying to make tps54202 switch regulator for esp32-wroom which would pass EMC test. https://www.ti.com/tool/TIDA-00948 By reading guidelines of designing they say that to pass EMC test you need to ...
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2answers
53 views

Is the TPS54202 buck converter a good solution to pass the FCC SDoC?

I want to design a PCB with the ESP32-WROOM module which has bluetooth. I want to pass the FCC verification. I would use a linear regulator, but it makes too much heat. My input is 14V car battery, ...
0
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1answer
30 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 ...
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5answers
2k views

On the possibility of steel nails as EMI filters

I live in a place where ferrite beads for EMI suppression are hard to get. I thought steel had a very high iron loss, especially at high frequencies. So is it possible at least theoretically to use ...
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2answers
79 views

Noise on stereo summing circuit from LED's

I've been a tinkerer and hobbyist for 20 years now, but mostly in software. I've done my fair share of simple soldering (replaced controller ports on an original Xbox with actual USB ports, for ...
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1answer
44 views

High frequency filter circuit design

I am a trying to design a design an Electrosurgical interference suppression (ESIS) protection layer to filter out high frequency noise caused by Electrosurgical equipment during surgery. I am using ...
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1answer
35 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 ...
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1answer
154 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 ...
2
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0answers
169 views

RFM69 hat for RPI get stuck because of noise caused by missing ground

I built a RFM69 hat for a Raspberry Pi 3 B+. It works perfectly as long as I do not use the GPIO to switch on the relay that drives a solenoid valve. Unfortunatelly a lot of times the switching cause ...
1
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1answer
32 views

Balanced impedance CM and DM stages EMI Filtering

Here is the following assertion : I would like to understand why line impedance imbalance can cause CM noise to get converted into DM noise ? Thank you very much !
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1answer
48 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 ...
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0answers
23 views

Cutoff frequency of Common mode part of EMI Filter?

Anybody knows how we can determine the cutoff frequency for the common mode parts of EMI Filter? I know for the differential mode we use FFT to find the highest harmonics of input current and then ...
0
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1answer
51 views

Using common mode choke in differential configuration for differential mode EMI filtering

Why is it not popular using common mode chokes in differential mode configuration for differential mode noise filtering? Mostly when using fly-wire type chokes with filters, where the chokes are ...
0
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1answer
60 views

How is the differential mode noise suppressed by adding a capacitor across the Lines

I was reading about the common mode noise and differential mode noise. I don't understand how a differential mode noise gets coupled and how adding a capacitor across the line will help. I ...
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0answers
30 views

wifi, emi and shielding analog circuit

Hi I am building an USB sound card circuit for raspberry pi. It involves a button, LED and Sound card IC PCM2912A (TI). I am mounting raspberry pi over the 2 sided pcb on top (top has full digital ...
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0answers
24 views

Rectifier and EMI filter for multiple led drivers

I try to make a power supply stage for 2 offline led drivers insted of making 2 different boards. Find in atteched file the design A and B. Could you explain and suggest me what is the best design to ...
0
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0answers
30 views

What's the LC filter arrangement on dual output DC/DC converters?

It's pretty hard to find a filter arrangement for a dual output converter, but I came across the following:- Taken from here. So for the bottom example, is the LC arrangement correct? I always ...
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0answers
34 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 ...
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0answers
40 views

Impacts of low-pass filter on micro-controller board

I have a micro-controller board, driving small DC servo motors and I control the angle via a PWM signal (50 Hz) and everything is alright. However, there is an oil gas motor, running next to the ...
2
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2answers
47 views

Questions regarding DC-DC converters powering transducers

Several of these transducers requires isolation as recommended here in their manual: The transducer models are uni-polar 0-10V output which require 24VDC power supplies. So at the moment there is a ...
2
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2answers
117 views

Is shielding the entire circuit with a faraday cage a good idea?

Let's suppose I have a circuit which contains a 3.3V MCU and a buck converter (let's think that its frequency is higher than 400 kHz). I'm wondering if shielding the entire circuit would not a good ...
2
votes
1answer
128 views

How can I generate a noisy environment to test my PCB?

I am developing a PCB project but i want to use the PCB in noisy environments (which usually contains 7.5-45 kW multiple motors with frequency inverters and also ignition transformers). I made some ...
0
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1answer
54 views

EMI Filter design capacitors problem

I'm trying to design an EMI filter for a 3-phase induction motor driver. I've looked at some example filter designs but in one of them I couldn't understand the capacitors and resistors what they are ...
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2answers
86 views

Shielding and Ground Loops - RF panel jacks for GPS

I've been working on a design that requires me to pass an RF signal through a conductive panel. I'm using SMA jacks for that purpose as they're readily available and also available in an isolated ...
0
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1answer
42 views

Calculating Capacitance / Rolloff Frequency for Across the Line RFI Supression

I’m in the process of restoring my first All American Five (AA5) tube radio – in this case, a GE Model 115 from the late 1940s. As I’m getting ready to order replacement capacitors for it, one of ...
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2answers
95 views

Will a 2.4GHz WiFI/Bluetooth antenna create noise in my sensitive EEG measurement circuit?

I'm designing a circuit for doing EEG measurements and I want it to be very compact. As a result, the WiFI+Bluetooth antenna (2.4GHz) will be sitting half an inch above the electrode inputs. Will this ...
0
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1answer
99 views

Can an isoSPI interface work without isolation?

Ive got a LTC6820 that I will be communicating with a LTC6811 and they both use isoSPI but all the example diagrams show the connections going through a transformers and twisted wire like this: But ...
2
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2answers
100 views

Connect MIDI input shield connection to ground with capacitor. What voltage / kind?

The midi specification mentions optional capacitors between connector shield and ground for a midi input: Neither the type of capacitor nor the voltage rating is specified. I would think that the ...
0
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1answer
174 views

How to connect an AC line filter

I am trying to connect an AC line filter (rated for 115/250VAC) on the load side of a 24VAC transformer (part# BPD2G, datasheet here). The first filter model I used is Delta's 03DBAW5. From the ...
0
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1answer
57 views

AC EMI filter specification

I am looking at the specifications of an EMI filter for single a phase ac application, and I noted that the datasheet specifies an operating frequency from DC-400Hz? Do you have any idea of what this ...
0
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1answer
243 views

Filtering out OLED electrical noise

I have an OLED display and a high gain op-amp on the same circuit. When OLED is powered on and displaying something, it creates a electrical noise on the output of the opamp. Here is what I tried: ...
2
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3answers
618 views

Why does PWM create lots of EMI and signal ground noise?

TI had a note to create DAC signals using PWM. http://www.ti.com/lit/ug/tidu027/tidu027.pdf Whereas I also found an article that says http://www.mosaic-industries.com/embedded-systems/...
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0answers
43 views

Dual Rail Switch Mode Power Supply Filtering

I'm looking at the datasheet for a dual rail SMPS I plan on using for analog circuits, and I'm wondering about how to interpret some recommended filtering circuits. I understand a simple filtering ...
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2answers
80 views

Grounding balanced secondary isolation transformer for EMI suppression

simulate this circuit – Schematic created using CircuitLab Which is the best secondary connection to clean the main line power from EMI, line noise and HF harmonics by using an isolation 1:1 ...
1
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1answer
166 views

How do I correctly protect my MCU from resetting during a current surge on RF transmission?

I designed a PCB with a SIM868 module for data transmission. On the PCB, the MCU resets randomly on transmission start of the SIM module. On a breadboard setup, it worked just fine, even without caps. ...
2
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1answer
48 views

Inductance value of PI-filter connectors?

I find myself in the situation of being forced to use filter connectors to solve an EMC issue very late in the project. Normally, this should of course be solved in circuit design, but as projects and ...
3
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1answer
161 views

Spark plug cable firing interrupts

I am building an electronic tachometer for an old motorbike (a moped). For RPM monitoring I have come up with a solution of painting part of magnet black and using a TCRT5000 reflective sensor which ...
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0answers
56 views

Some more problem caused by EMI

Before, I asked some ways to solve the EMI problem and I got some useful answer from here: Really occasional malfunction of the Schmitt-trigger input - Really occasional malfunction of the Schmitt-...
0
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2answers
136 views

How much power can electrical noise (EMI) produce?

I have a 5-meter-long wire connected to an ESP8266 input. The wire is connected to a regular wall-mounted switch and goes through my room's wall and is adjacent to mains power lines. As you would ...
10
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3answers
2k views

Reduce EMI generated by old AC motor from an electric knife

I have an old electric knife (220V 50Hz) which seems to produce a lot of EMI. Some clues on that were a "bzzzz" noise from PC speaker I noticed sometimes when someone use it. Recently I bought a ...
1
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1answer
160 views

Coupled DC/DC-modules - correct input filtering

According to the support from TracoPower I use two THN-30WI modules (­±15V) in conjunction as shown below (without each C1 and C2) to produce ±30V. This works but I get a lot of noise. The ...
0
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1answer
54 views

LC filter applicability for power to output cables

I am designing a circuit that has a 240MHz MCU and some cables going to sensors so I am wanting to reduce the clock noise getting onto the supply line and going out the cables by using an LC filter. ...
1
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2answers
203 views

Distance required between two wires to avoid EMI

I am running 3 cables cables from a solar heater down to my apartment (around 12 meters), one to power an electric heater and water pump (around 2000 watts in total), one to control a 12V solenoid and ...
0
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1answer
63 views

Issues with designing ground plane for switching relays in high noise environment

I am designing a PC Controlled 8 channel Relay using AVR microcontroller. Here, the relays are on the right side of the board and are controlled by the AVR micro on the left side. The eight TTL ...
3
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1answer
126 views

Problem while simulating EMI Filter for power lines

I was designing an EMI Filter for the CE102 standard. I was a bit confused on how to provide noise source to the circuit, since (as of my knowledge) EMI noise enters our system by parasitic ...
0
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1answer
128 views

How to deal with an inconsistent / noisy power signal?

I'm using a 12v power supply to operate a system of sensors that is very sensitive to fluctuations in the voltage input. Unfortunately, I can't control what goes on upstream of my components and this ...
1
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0answers
95 views

Linear power supply and mains filtering and protection

I'm designing my first linear power supply for my project which needs dual rail 12V (the regulation from 15V to 12V is on another board, 7812 and 7912). The +12V (+15V) rail will draw about 250mA, the ...
0
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1answer
257 views

Using a line filter transformer for audio? [closed]

I've read that line filter transformers (like the one on the image) attenuate EMI between AC mains and an electronic circuit. Will the RF attenuation also work if I used one of these on audio input ...
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1answer
139 views

Need help to newbie to understand MIL-STD-461 [closed]

why only 10khz-10Mhz is used for CE102 test ? why not other frequency range is used for CE102 test ?
2
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1answer
615 views

Automotive battery input EMI filtering

I'm reviewing the schematics for an evaluation board, which uses an LC filter on the DC input as shown here: PWR_IN is defined for the evaluation board as being 7-27V. The issue I'm facing, is where ...