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Questions tagged [emi-filtering]

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0
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1answer
34 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 ...
-1
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0answers
37 views

Input filters on AC/DC converter

I am using a board mount AC/DC converter and after adding an LC filter at the DC output of the converter to remove high frequency noise going to the circuitry, the noise is now reflecting back down ...
0
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1answer
31 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
vote
1answer
57 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
44 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
votes
1answer
67 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
votes
1answer
39 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
49 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
66 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 ...
-3
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1answer
85 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 ?
1
vote
1answer
92 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
votes
1answer
144 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 ...
0
votes
1answer
66 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
105 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 ...
2
votes
1answer
118 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
282 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: ???
0
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2answers
49 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 ...
0
votes
0answers
54 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, "...
1
vote
2answers
696 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, ...
6
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2answers
245 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 ...
0
votes
0answers
59 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
votes
1answer
38 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:/...
0
votes
1answer
47 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 ...
1
vote
2answers
140 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 ...
1
vote
1answer
184 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
votes
1answer
153 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 ...
0
votes
1answer
53 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 ...
2
votes
0answers
209 views

Adding a ferrite bead to source of mosfet (smps)

We are designing a SMPS (ultra low noise) based on TI schematics http://www.ti.com/lit/df/tidrgc2/tidrgc2.pdf (5V, 15W quasi resonant) In order to reduce EMI (we have some ringing across Mosfet when ...
1
vote
2answers
125 views

Understanding topology for EMI supression in a power supply

I am using an isolated DC/DC converter to supply a MOSFET's gate drive, in a high frequency and high voltage application, so I am concerned about the EMI in my design. In the website of the ...
0
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2answers
174 views

Effect of Isolated Power Supply EMI Filter Bypass Capacitor

I am using this isolated DC-DC converter as a power supply to ensure regulated 12.0V: Traco Power TEN60-1212N. In the application notes, the following EMI filter is suggested: with L1 = 3.3µH, C1,C4 =...
0
votes
2answers
85 views

Can someone explain how this RFI filter works?

This is an RFI filter from a 12V automotive DC motor. This motor design is over 20 years old and currently in "service" production. We just learned that the capacitor we're using is now in short ...
0
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1answer
239 views

RC snubber across mosfet or diode with ferrite bead [closed]

I already designed a RC snubber across a mosfet and diode successfully . Reading through some whitepapers , I have seen the addition of a ferrite bead in series with RC snubber. Do you recommend it ...
0
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1answer
105 views

MCU Design, maximum wire length per frequency and characteristic

I'm getting pretty deep into MCU design and I've run into a problem for which I'd like to find a formula. In circuit path design how can I correlate max wire length to max transmission frequency on ...
0
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2answers
48 views

Which option of bonding multiple strands from Cat5 pick up the lowest level of EMI?

Caviat I am not an EE major, nor have I had the opportunity to study general EE principles. At best, I could be considered a weekend hobbyist. This is my first time posting to this SE site. Some ...
0
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0answers
167 views

SCR switching conducted emissions

I have a circuit that drives a 240Vac line to line power to a resistive load. I am testing for radiated and conducted emissions. Radiated emissions went fine but conducted emissions failed with "broad ...
0
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2answers
74 views

Isolated power supply for measurement

I have to measure potentiometer sensor value in a noisy environment (car). The sensor is about 3 meters from my main processor board, my idea was to simply use this sensor as voltage divider and read ...
0
votes
1answer
202 views

PCB layout for shunting RF common-mode current to chassis

I am laying out a pcb with a number of external connectors that will have RF common-mode filters at each connector, shunting any common-mode signals to the chassis. However, I'm not sure what is the ...
0
votes
1answer
280 views

LAN9500AI (USB to Ethernet IC) hang if Ethernet cable removed

I need some help on debugging the issue faced on USB to Ethernet design. I have took reference form LAN9500Ai Development board. Issue:- When Turn on the Power , USB to Ethernet work, and Three LED ...
3
votes
1answer
78 views

Protecting digital electronics from nearby high voltage sparks

I am controlling a high voltage power supply to generate corona discharge. To switch it on and off I am using an AC relay controlled by a microcontroller as shown in the figure. The controller ...
3
votes
1answer
619 views

Common mode choke in circuit with multiple ground connections

I'm designing an automotive circuit where I'm using a reference power design from TI. Together with protection circuitry, this design includes a common mode choke. The same circuit has an antenna ...
25
votes
2answers
5k views

What is an “XY” rated safety capacitor, exactly?

Please help me understand this. In a prominent, 480v, 6kW AC servo drive, across three input phases, three 22mm "XY" class 10nF caps are placed for EMI suppression. Also, from these three phases, ...
1
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2answers
431 views

Reducing EMI emission from 20KHz PWM

I have a small 1.5A @ 12V (~10 Amp stall current @ 12Vdc) DC Brushed motor connected to a H-Bridge switched with 20KHz PWM. The motor is connected to the bridge through a 3 meters long cable: [H ...
3
votes
1answer
345 views

Correct SPI, I2C termination and EMI limiter for external bus?

[EDIT] This question has been edited. The bus does not split anymore. The entire question and figures has been edited. BACKGROUND I'm using an ATSAM3U2E and want to include both the SPI and I2C bus ...
0
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2answers
86 views

How to select an EMI suppressor

I have come to the part in my construction where I suppress EMI. I just need a little help on how to select the right one. I'm using two RT8259 switch regulators (switching at 1.4MHz) and want to ...
1
vote
0answers
189 views

Transfer function of EMI filter

In order to define the transfer function of an EMI filter, I want to know if I need to define the equivalent circuit in CM and in DM to calculate the total transfer function of the filter below:
1
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1answer
113 views

Radiated Emissions

I have been performing some EMC testing on a product (which I didnt design) Its been a right barrel of laughs and it was quite challenging decreasing the radiated emissions below the 50dBuV/m limit ...
0
votes
1answer
560 views

Leakage current in in-line mains filters

I have an two inline (EMI) filters. One with the rating (as given in datasheet): LEAKAGE CURRENT: EACH LINE TO GROUND A. @ 115 VAC 60Hz............................0.20 mA MAX B. @ 250 VAC 50Hz.........
0
votes
3answers
512 views

using ferrite beads khz region - advice?

I am operating some mosfets in the 50-500khz range, and wish to improve performance, reduce losses and very important reduce emi. I am using a resistor on the gate on the drive with a 12v zener and ...
0
votes
0answers
184 views

What causes 1000Hz (and multiples) electromagnetic interference?

When recording old analog synthesizers (different brands and models) I'm getting interference in the audio. This started suddenly about two years ago (I thought the synth I was using was ...
0
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0answers
107 views

How can I measure Impedance of the transformer without using VNA and impedance analyzer practically?

How can I measure Impedance of the transformer without using VNA and impedance analyzer practically? The impedance measured on a high-frequency transformer may range from 1m ohm to 1M ohm.The ...