Questions tagged [interference]
For questions about electromagnetic interference (EMI); see also the [emc] tag.
391
questions
3
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1
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Strong deviations in weight measurements, possibly after connecting a high current device on the same line
I have the following situation, where there's a sensitive scale connected to mains voltage (but they have their own AC-DC power supply).
Someone connected a device that requires very high power in the ...
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0
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1
answer
34
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ESP32 protoboard wifi not working due to jumper wires?
I made a prototype board (pics below) with a ESP32-C3 board that has a ceramic antenna. I'm a beginner for hardware stuff, but I soldered everything and it works just fine. I then made a second one ...
- 157
0
votes
0
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83
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Common Mode choke for radio interference
Wondering if anyone could guide me in a good direction.
This schematic go top redesigned for better protection, so top half become whats shown.
After that we started to notice that when XL4005 outputs ...
0
votes
1
answer
87
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Why are green pair (or orange pair) wires not adjacent in RJ45 connectors?
For the sake of the discussion, let's talk about T-568B, but this applies to T-568A as well.
I've searched a bit for why the green cables are not adjacent, and the answer was that this reduces ...
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0
votes
1
answer
66
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Troubleshoot negative reading from thermistor sensor when the projector powers on
I'm in the process of fixing Epson EB-E500 projector lamp/temperature error. The projector turns on correctly, it displays the interface and after about 15 seconds the display shuts off and the fans ...
0
votes
0
answers
59
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ESP-8266 doesn't boot on particular power supply
I have an ESP-01 board (small board with ESP-8266) that usually works fine, but with one particular power supply, the LED just flashes rapidly and the module doesn't start. I know that these modules ...
- 101
0
votes
2
answers
160
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Best way to get 80 wires down to 1? Is it even possible? [closed]
I'm new to working with power supplies but I'm planning on using two switching 24 V/40 A/960 W power supplies connected parallel. This power needs to connect to around 160 wires, 80 on each side of a ...
0
votes
2
answers
69
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Localized interference between 2 distant points [closed]
Lets say an emitter sends a directional carrier wave of 60 Hz that can travel up to 100 km.
Then, at 50 km from source, another weaker wave of 60 Hz is emitted.
This weaker wave is off phase compared ...
1
vote
1
answer
49
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TDM signals crossing
I'm working on a 2-layer PCB design and trying to do the best I can for signal integrity. I have 2 TDM lines and at a certain point they cross between each other. See image below.
Is this likely to ...
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2
votes
1
answer
70
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How can I shield electronic devices against interference from a plasma cutter? [closed]
I am trying to build an NC plasma cutter with a 3D printer. This was the setup:
To do some tests I've mounted the plasma torch (Parkside) to the printer's (Creality CR-10) carriage. The button on the ...
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1
vote
0
answers
47
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Conducted Emissions from a PoE powered equipment according to En55032/CISPR32
I'm seeking clarification on Conducted Emissions measurements for a PoE powered device. I've reviewed both the CISPR32 and CISPR 16-2-3 standards, yet I couldn't find specific guidance on the setup ...
- 554
0
votes
0
answers
42
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Are small analog signals more or less susceptible to interference with a DC offset applied?
Per the title--when looking at analog instrumentation signals ("AC" for this purpose) traveling over a cable (in the realm of say 1-2Vpp) are those signals more or less likely to be impacted ...
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17
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5
answers
3k
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Can two interfering light beams create radio waves?
Two sound frequencies differing in only a few hertz can create ‘beats’ and this has been popularized in music designed to produce ‘binaural beats’. Can two lasers be tuned in a similar fashion so that ...
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0
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0
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46
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PIR Sensor Interference When RF Transmitting
I have created a small DIY circuit which sends a signal over 433.92Mhz when a PIR sensor is triggered.
The circuit consists of 4 modules soldered onto stripboard.
Schematic:
Components are:
0.71mm ...
- 179
0
votes
0
answers
62
views
ESP32 shielding inside an inverter
I am thinking about using an ESP32 as a secondary controller for a 12 V DC to 220 V AC inverter to monitor and control overload, low battery, using relays to switch AC output, etc. The inverter will ...
- 624
1
vote
2
answers
133
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How can it be possible that I hear people's voices from my computer speaker? [closed]
I searched on the web and found it can apparently be due to truck drivers communicating on citizen's band radio which is around 20 MHz. Apparently this communication may cause interference with the ...
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2
votes
1
answer
93
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Mysterious artifacts in my strain gauge data. Can anyone suggest a possible source? [closed]
I'm working on a project where we are collecting timeseries data from multiple strain gauges. We are seeing a strange pattern of artifacts in our data.
The artifacts appear as sharp 'spikes' with a ...
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0
votes
1
answer
56
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Tuned RF circuit: How to minimise interference?
The circuit in Figure 1 is designed to detect an RF signal at f0=40kHz. For information, this will be a portable proximity sensor, worn on a cat's collar, so it has be small and light.
The circuit ...
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0
votes
1
answer
114
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ESP32 powered over long lines with 230V
I'm planning to put several Ethernet ESP32s with AMS1117 5 V to 3.3 V power converters and SHT31 temperature sensors around my house to report temperatures. They will be connected over Ethernet; power ...
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2
votes
1
answer
48
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Is there a risk of damaging built in RF components having several Iridium SBD 9603N modems active close to each others?
I use Iridium SBD 9603 N modems in some hardware (oceanographic buoys). I use high gain antenna, typically the setup is based on https://www.sparkfun.com/products/18712 and https://www.sparkfun.com/...
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1
vote
1
answer
155
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Unexpected signal at AD620 module output when Vsupply is on
I bought an AD620 instrumentation amplifier module and below is the module schematic.
Souurce - https://protosupplies.com/product/ad620-instrumentation-amplifier-module/
A problem shows up when I'm ...
- 141
0
votes
0
answers
53
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Pump motor interference with PIC microcontroller
I am building a fermentation chamber for sourdough which has a heating element and a 5v mini-pump for humidity. Both are controller by a PIC16 microcontroller. Without the pump all is well, but as ...
0
votes
1
answer
52
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Precautions when using multiple analog devices on same circuit
I have a KP236N6165XTMA1 5V analog pressure sensor and a SHT31-ARP-B 3.3V analog temperature and humidity sensor on the same circuit, connected to the same ground plane (see v0.2 schematic bellow).
...
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1
vote
1
answer
85
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Will termination resistors help with USB data line "dead legs"?
I'm designing a USB switch, using small relays to connect a USB peripheral to any one of ten PCs.
The USB traces from the peripheral branch out to ten different relays. I anticipate these "dead ...
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0
votes
1
answer
122
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Multiple DC/DC or single DC/DC + LDO
My FSAE team and I are developing the electronic boards for the car, like BSPD, TSAL, etc.
So far, we use a 24V battery for low voltage system with a single DC/DC 24V to 5V converter for each board, ...
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-1
votes
2
answers
4k
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Power supply makes a static/coil whine noise when the power supply is off and the PC is off
I have noticed that my power supply (PSU) makes a VERY slight coil whine/static noise while it is plugged into the power outlet, regardless of the power status of the PC and the PSU. It sounds no ...
- 1
1
vote
2
answers
115
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How can I protect this gate signal trace from EMI?
I'm designing this board which will control current through a coil using an IGBT. The coil is 500 uH and is mounted around 3 cm above the PCB and will handle peaks of 400 A. Because of the close ...
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3
votes
1
answer
93
views
Stepper Motor Interference from Metal on Frame or Shaft
I'm working on a project with a stepper motor and am running into an odd interference issue related to metal contact with the motor.
I'm using a StepperOnline Nema23 2.8A (23HS22-2804S) motor with a ...
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0
votes
0
answers
71
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How to shield a wireless microphone receiver from hdmi cables running under it?
We have some wireless microphones set up with the receivers in a confined space. After adding some HDMI cables (for streaming purposes) we now have an interference problem.
While the transmitter is ...
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2
votes
2
answers
224
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Could a device connected to one MCB/phase affect a device on another MCB/phase?
I have a 3-phase 230V residential supply. It's divided among 3 groups of MCBs all powering single phase devices.
The problem I'm having is that whenever the air conditioning (single phase) turns on ...
- 167
0
votes
0
answers
71
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How to eliminate the VFD noise affecting digital sensor reading?
I have a problem getting correct readings from a 5v digital sensor connected to an Arduino Uno board. I get correct reading until I start the VFD that drives a 3-phase motor.
The sensor reading then ...
- 364
0
votes
1
answer
282
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Relay Switching Causing Arduino to Crash when Load Attached to Relay
The title pretty much says it all
When we don't have devices attached to the relay (standard 4 relay module board) this doesn't happen. But when there are devices attached this does cause the problem ...
- 123
1
vote
0
answers
47
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Mitigating 2.4GHz interference from 0-5V analog signaling line
I am chasing my tail on a project and cannot seem to find a way out of the hole.
I have a small 18mm 40kHz piezo transducer running through a powered precision rectifier+preamp circuit. This tiny ...
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0
votes
1
answer
142
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VFD interference with microcontroller
I’m doing a project that requires the control of a VFD (variable frequency drive) that powers a motor by using a microcontroller to send the signals.
When the VFD is powering the motor, there is a lot ...
2
votes
1
answer
159
views
Treadmill charges electrostatically, creating interferences with my PC [closed]
I have been using a treadmill for around 10 months, then it started causing my PC to detect connection and disconnection of my keyboard.
It took me a while to realise that the treadmill was the source ...
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3
votes
3
answers
379
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Why is inductive coupling negligible at low frequencies?
I've been reading some papers from the early telephone era. I see a lot of statements thrown around like "crosstalk at low or voice frequencies, where inductive coupling is negligible..." ...
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1
vote
2
answers
145
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variable speed drive interfering with distant PHEV charger
I am using a generic variable speed drive for a water pump.
About 5% of the time that I run it, it stops my BMW 530e PHEV from charging. What is the most likely cause? What measurements can I make to ...
- 441
0
votes
1
answer
40
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Interference of RF currents with a combiner
I am trying to understand what happens to 2 RF currents flowing in separate planar waveguides (such as microstrip lines), when combined with a power combiner.
More specifically, will they interfere, ...
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0
votes
4
answers
129
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Weird component in radio player interferes with FM functionality of the radio itself
I got my hands on an old radio player which has both cassette player and FM/AM functionality. I got constant noises while playing on FM and it turns out to be some weird component on the cassette ...
2
votes
1
answer
193
views
Picking a pi- or T-filter to suppress radiated interference on supply line
Normally when I design suppression filters I use π-filters for data lines and T-filters for supply lines as supplies generally have a lower output impedance than data pins.
I now have the situation ...
- 121
7
votes
2
answers
3k
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USB shielding, device or host side?
I have an SBC with a USB host port, but it is exposed as male header pins rather than a female USB port.
I have soldered female headers to a USB cable and have a working but intermittant connection, ...
- 439
1
vote
0
answers
89
views
Second shift register 74HC595 with wrong outputs
I have a controlling panel at my wall to control which electrical device is active (because I have only a single 10 A phase and running way to often to the breaker).
The principle is easy: read Input ...
0
votes
1
answer
50
views
Would grounded conductors placed on skin prevent signals from reaching a shielded body part?
Here is the scenario:
You are in an environment where there are sources of EM signals that your body will pick up as though it were an antenna via capacitive coupling, i.e. what happens with the 50/...
2
votes
1
answer
84
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Understanding opamp circuit, 13 MHz (interference?) amplification
I have the circuit drawn below soldered to a prototyping board.
First, I added a high-pass filter a with cutoff-frequency of 600 kHz, since I would like to receive around 2 MHz.
Then the received ...
- 376
0
votes
1
answer
158
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Why does EMI from a DC motor lock up my Arduino, while consumer electronics remain unaffected? [closed]
For example: my laptop, while connected to the Arduino over USB, runs just fine, while the Arduino locks up.
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1
vote
1
answer
292
views
Two laser diodes beat frequency
With a single laser diode, the interference pattern of the light with itself gives a beat frequency of zero.
Given two laser diodes (same wavelength, same manufacturer), the interference pattern of ...
1
vote
1
answer
213
views
Two transformers with common ground (Split supply)
When and where you can have a common ground? In this case between 2 different transformers. The initial goal is to have:
One Ground
-15 V
+15 V
+12 V
The split 15 volt supply will be used for ...
- 11
0
votes
0
answers
130
views
How does an integrating receiver work?
I am reading some papers and in one paper, the working of an integrating receiver is mentioned to remove (periodic) interference from the received signal. The paper explains the working as such:
The ...
- 376
0
votes
0
answers
83
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Intersymbol interference on PAM Trasmitter
I would like to simulate on Matlab a PAM signal which, travelling on a time-dispersive communication channel, contains intersymbol interference (ISI).
I have 'built' the transmitter by generating:
8-...
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11
votes
3
answers
2k
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Why does a 50 Hz, 200 mV sine wave appear sometimes on my portable oscilloscope without a probe connected to anything?
I have a portable oscilloscope, and when I connect just one probe to it, sometimes, moving the probe into the air without connecting it to anything, then I can see (in some of the places of my house) ...
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