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Questions tagged [emi-filtering]

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27 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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26 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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38 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 ...
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2answers
40 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 ...
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2answers
110 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 ...
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1answer
115 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 ...
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1answer
43 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
70 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 ...
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1answer
32 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
80 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 ...
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1answer
49 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 ...
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2answers
67 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 ...
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1answer
73 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 ...
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1answer
49 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 ...
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120 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: ...
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3answers
436 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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34 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
58 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 ...
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1answer
162 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
41 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
149 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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54 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-...
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2answers
124 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 ...
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3answers
1k 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 ...
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1answer
120 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 ...
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1answer
46 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. ...
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2answers
170 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
57 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
106 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 ...
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1answer
92 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 ...
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0answers
79 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 ...
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1answer
204 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
118 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 ?
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1answer
400 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 ...
2
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1answer
152 views

Airport radar is interfering with my circuitry

I am using an arduino, but this is not an arduino question. And unfortunately, I cannot share my schematic. I can tell you though that I have a stack of three arduino-sized boards which create two ...
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1answer
108 views

PC monitor flickers/resets when washer motor switches on or off [closed]

My room is next to our laundry and I've recently got a new PC monitor. I've noticed each time the motor in the washing machine is switched on or off, my monitor flickers/resets. The monitor is 32" but ...
0
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1answer
205 views

Impedance mismatch in LISN for EMI/EMC test

I am currently designing LISN for CE-102 test.The schematic of the circuit is provided below. When I connect the circuit to the network analyzer the impedance is coming as shown below expected graph ...
3
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1answer
171 views

Suppressing “travelling” EMI spikes

I am working on a circuit with a AC to DC power supply module and wireless MCU module. The MCU operates at 240MHz and on the power input to the module there are 2 x 0.1uF capacitors and a 22uF ...
4
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3answers
412 views

PCB design - signal loops

I've read about loops that a PCB designer should avoid them "mostly about ground loops" but i think I've read also about power. so in this case, is this wrong: ???
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2answers
60 views

what happen if I use EMI filter at more then specified current

I want to use Gaia EMI filter. my load requirement is 1.7 A continuous and 3.5A Max. Voltage is 28 V. Because of the max current I have to use FGDS-10A-50V(load current can go up to 10A) but this size ...
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0answers
98 views

How to prevent EMI from affecting transistor

I am working on a simple APRS tracker. The schematic is here: It's not on a PCB, but just on a protoboard: The problem: Q1 transistor activates the push-to-talk on a handheld VHF transceiver, "...
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2answers
742 views

Why does an SMPS use LCR on INPUT?

I have this 5 V output SMPS I bought a while ago. I was wondering why there are LCRs connected to the input of my SMPS. I don't understand why it's there. BTW, I'm an electrical engineering student, ...
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2answers
471 views

5.5 kHz noise on SMPS output

I am designing a low noise SMPS like this http://www.ti.com/lit/df/tidrgc2/tidrgc2.pdf switching from 40-90 kHz. I have a weird problem, on the output we are seeing a spike of noise at 5.5 kHz and ...
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0answers
63 views

Troubleshooting noise pickup near AC motors

I have a 2-layer PCB with ADC communicating using SPI. This board is to be used with a National Instruments (NI, LabVIEW) FPGA, with a clock rate up to approximately 600kHz (higher would be nice, but ...
0
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1answer
59 views

ACM2012-900-2P filter can be used on USB 3.0 lines of a Type-C connector?

I have doubts that this CMF is recommended for USB3.0 due to his bandwidth. I am afraid it will filter the USB signal. Can someone explain better the SCCC21 and SDS21 characteristics from here? https:/...
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1answer
113 views

Protection against EMI for an RFID reader

I've designed a base board for a Velleman VMA405 (13.56 MHz) RFID reader based on MFRC522 IC. But, due to interference from the base board (I'm assuming the oscillator), the reading range is limited ...
2
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2answers
259 views

Does a 3-winding common mode choke work on PE wire

Update It was pointed out the PE wire has to carry large current in fault condition so using a 3-phase CMC is problematic. In IEC62368-1 (2nd edition) chapters 5.6.3 and 5.6.4 it is implied that the ...
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1answer
289 views

Protection against EMI

I have a complex EMI problem. There is a RPi Compute Module along with a LAN9512 and GSM modem (M66). Layout guidelines are strictly following the datasheets' recommendations, I don't think there is ...
0
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1answer
324 views

does the orientation of a choke in an LVDS application matter?

I found the diagram below online while looking for information on the orientation of a choke I intend to use in an LVDS application. Does the orientation of the choke matter? The part I intend to use ...
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1answer
83 views

RC snubber on Mosfet (smps) max C

I am designing a SMPS from TI http://www.ti.com/lit/df/tidrgc2/tidrgc2.pdf We replaced the Mosfet fro schematic with STL11N65M5 that has a Coss of 18pf So I am designing a RC snubber across it and I ...