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Questions tagged [interference]

For questions about electromagnetic interference (EMI); see also the [emc] tag.

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1 answer
150 views

LTC5599: why are these baseband inputs passed through 49.9 ohms and the capacitor + SPI

I'm designing a radar transceiver board using the LTC5599. In the datasheet for the part, there is a schematic that shows the circuit configuration for the evaluation board. Here is an image of the ...
0 votes
0 answers
58 views

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 ...
1 vote
1 answer
145 views

Simulate power of intermodulation products

I would like to predict if in- and out-of-band interference will hurt my ability to read signals in the 902-928MHz spectrum. I recorded the maximum received interference power from 10MHz to 3GHz ...
0 votes
1 answer
271 views

Arduino relay module interferece on signal pin (230VAC motor load)

I'm trying to switch a small 230V AC motor using an Arduino Uno, but I'm having same problems due to interference on the relay (so the Arduino itself is not a problem). Sometimes the module create ...
0 votes
2 answers
159 views

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 ...
35 votes
5 answers
22k views

How come radio signals don't interfere with each other all the time?

I'm a newbie on wireless technologies and I'm trying to understand how they work. One thing I don't understand is this: How come transmissions from different devices don't interfere with each other ...
0 votes
2 answers
69 views

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
43 views

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 ...
0 votes
1 answer
249 views

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 ...
2 votes
1 answer
57 views

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 ...
1 vote
0 answers
38 views

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 ...
0 votes
0 answers
42 views

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 ...
3 votes
1 answer
344 views

Weird SWD debug port behaviour

Today I have started to encounter strange problems with SWD debugging. The debug only works if I keep my finger on the SWD pins. To be more interesting I have the same problem with the boards I was ...
17 votes
5 answers
3k views

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 ...
6 votes
4 answers
1k views

Does a twisted pair cable radiate more EM radiation than non-twisted pair?

I am looking at many electronic forums and people always come up with different answers, so I would like to settle this question once and for all. Does a twisted pair cable radiate more EM radiation ...
0 votes
0 answers
39 views

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 ...
-1 votes
1 answer
7k views

Can a ferrite choke/bead suppress unwanted audio signals (maybe mobile phone induced)?

I use a headset with a normal 3.5mm audio cable (not USB). Most times I have excellent audio quality, but in a large office building, I sometimes get very bad signals injected from an unknown source. ...
0 votes
0 answers
51 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 ...
1 vote
2 answers
130 views

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 ...
2 votes
1 answer
89 views

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 ...
0 votes
1 answer
46 views

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 ...
0 votes
1 answer
101 views

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 ...
2 votes
1 answer
45 views

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/...
1 vote
1 answer
110 views

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 ...
1 vote
3 answers
506 views

I2C noise from 433MHz transmitter

I have built a little thermostat based on BMP280 temperature sensor over I2C, ESP8266 Lolin v3 and STX882 433Mhz transmitter. I have not added additional pull-up resistors or decoupling capacitors. ...
-1 votes
2 answers
3k views

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 votes
1 answer
539 views

Bluetooth antenna on top of large metal object and other RF questions

I've been doing some research on RF antenna design considerations but haven't really found anything close to the situation my device will be in. I am designing a wireless sensor for my FSAE team that ...
3 votes
1 answer
86 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 ...
0 votes
0 answers
53 views

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
47 views

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). ...
0 votes
1 answer
118 views

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, ...
1 vote
1 answer
84 views

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 ...
1 vote
2 answers
109 views

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 ...
0 votes
3 answers
301 views

Relay is switching by touching optocoupler with finger

To switch a 12V relay with a micro controller, I designed ("borrowed") this schematic. Build the pcb and it works great. But there's a little bug that got me a bit worried. If I touch the ...
3 votes
2 answers
195 views

GSM Interference with Meanwell Switch mode PSU

I am having trouble with interference from a GSM modem and my switch mode PSU. I do not know much about interference and how the radiation patterns works for GSM. Below is an image of the circuit ...
0 votes
0 answers
61 views

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 ...
1 vote
1 answer
475 views

Can ferrite beads deal with electromagnetic interference on attached PC peripherals?

This questions is more related to computer + external electromagnetic interference with my PC. I'm using a PC where one USB 3.2 Gen2 port is occupied with a USB 3.0 USB hub. I'm facing problem with ...
1 vote
2 answers
1k views

DC brush motor EMI

What kind of frequency does a DC brush motor generate? There are a few explanations online as to what causes EMI in DC brush motors (commutator sparking for example) and how to reduce it, but no ...
2 votes
2 answers
207 views

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 ...
0 votes
0 answers
71 views

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 ...
1 vote
0 answers
46 views

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 ...
0 votes
1 answer
127 views

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 ...
1 vote
2 answers
144 views

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 ...
42 votes
3 answers
44k views

Does Bluetooth interfere with WiFi?

I've read that WiFi b/g/n is using 2.3995 to 2.4845 GHz. Bluetooth is in between: 2.4000 to 2.4835 GHz. So what will happen when I put a Bluetooth sending device next to a WiFi sending device? Will ...
2 votes
1 answer
144 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 ...
2 votes
1 answer
83 views

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 ...
3 votes
3 answers
364 views

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..." ...
17 votes
13 answers
5k views

Is it possible that the phases of the moon could have an effect on the operation of certain types of electronics?

What type, what could the potential effects be, and why would this happen? EDIT: Yes, I am talking about physics not the supernatural. I figured this would be obvious unless people thought I was ...
4 votes
1 answer
322 views

When are 1:1 baluns worth it?

I am trying to build an antenna to connect to the GOES-16 satellite (downlink at 1690,1MHz, linear polarization) with my SDR. My plans are using a 1m offset parabolic dish with a biquad feed connected ...
31 votes
5 answers
28k views

What is causing large oscillations in my DC/DC boost converter? Is this ground bounce or some other effect?

I designed my first PCB for a DC-DC boost converter only to find that it produced very noisy output. The design is based around the MIC2253. Here's a schematic: Although my circuit allows for ...

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