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Questions tagged [groundloops]

Current flowing between two distinct references which are assumed to be at the same voltage, but in fact are not; typically this current flows through unexpected or undesired paths

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19 views

Chassis ground with multiple isolated power domains

Referencing this excellent question & answer Chassis ground question, how does one handle multiple isolated power domains? Eg. 3.3v for digital circuits 24v for serial connections 24v for ...
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2answers
2k views

Is this a case of ground loop?

I'm trying to power a 24V DC motor using 2x 12V batteries, an Arduino and a Cytron MD10C Motor Driver. I followed the description on Cytron's website for how to connect the Arduino and the motor to ...
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1answer
104 views

How can I eliminate the loop in this diagram?

I'm really sorry to open some series of questions but since the issue is complicated I decided to open a separate question for a particular thing for not creating confusion: There is the red loop in ...
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2answers
45 views

Need help to find the ground loop path in this diagram

I have been told that there is a ground loop in this diagram especially via USB_GND, Power-, GND. But I don't understand what that means. All the power supplies are SMPS. Can someone draw the loop on ...
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1answer
73 views

Crossing ground planes with low current low frequency signals

I have a board which has two ground planes, analog and digital, that on this board are completely separate. The grounds connect on another board, which is connected via a flat cable. All signals on ...
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1answer
41 views

Stepper Driver signal noise problem (Ground Loop)

I have an BluePill board (Arm Cortex M3 Dev. Board). Also a a4988 stepper motor driver. BluePill is powered from usb of my PC. Stepper motor driver is powered by external power supply which is 220V -> ...
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1answer
55 views

Why is the usb shield always tied to ground (GND pin)?

The shielding on a cable is to avoid interference from the outside world however it is always tied directly to the GND pin. Not inside the cable itself but inside a device. Every single device I take ...
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2answers
47 views

Is grounding necessary for a re-purposed laptop charging brick? [closed]

If I have re-purposed a laptop power brick, is it important to ground it or in certain use cases could one get away without earthing the power brick? I bought a class D amplifier board off eBay ...
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101 views

First 4-Layer Board + Layout advice please ( possible gnd loop solution ?)

This is my first 4 Layer layout. I've done many 2 layer boards in the past, but to be honest, I've been doing boards without taking special care when working with mixed signals ( Analog, digital and ...
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3answers
2k views

Is it ever bad to run an IC VCC trace next to a ground plane with 1mm clearance?

Since my last board flopped, I looked at it again and noticed a ground loop (because the DB9 casing completed the loop). Now I adjusted my board so that there is no loop of any kind. Instead, I'm ...
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1answer
66 views

What options are available for measuring grounded thermocouples?

I'm using 4 MAX31855 ICs to measure 4 K-type thermocouples and realized that 2 of my thermocouples have grounded junctions; I simultaneously also realized the MAX31855 is stated to not support ...
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1answer
100 views

How to break this ground loop in my car?

Here's the schematic for my car: simulate this circuit – Schematic created using CircuitLab The head unit is referenced to car's chassis. My amplifier and DSP are in the trunk. The DSP has an ...
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0answers
174 views

Why did this arduino burn out? SilentStepStick (TMC2130) stepper at 24V

I'm new to electronics. Attempting to bench-test a SilentStepStick stepper driver board, (based on a TMC2130) Using: Arduino Uno, a SilentStepStick driver board, a 0.6A stepper motor, and waterott ...
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0answers
121 views

RS232 signal ground

I have serial sensor wich i need to connect to a datalogger via RS232 interface. Sensor powered by datalogger. But datalogger have no signal ground pin, only power ground. So i connected sensors ...
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1answer
70 views

Gounding for EMI and signal integrity - LED Matrix multiboard design

I would like to implement a LED Matrix circuit like this one, where the LED matrix enclosed within the blue dots will be on a seperate PCB than the rest of the circuit. Since this will be a ...
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3answers
275 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
72 views

How can I power a device under test in a way that is safe for an oscilloscope?

Is it possible to power a circuit in such a way that makes it impossible to fry my oscilloscope with a ground loop? I've heard using a battery is a good way to prevent this. Is there a other way I ...
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2answers
91 views

Ground loop via pull-down resistor

I'm developing an STM32-based device, one of whose functions is to periodically monitor the main power 12V battery voltage. I created a simple switching circuit with a voltage divider. I have added a ...
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2answers
97 views

Oscilloscope ground-probe causing test circuit to malfunction [duplicate]

Today I was trying to measure the rectified SMPS incoming power supply ( 315VDC) using a tektronix TDS 3932C oscilloscope with P6139A probe. Every time the ground-probe touches the ground of the ...
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1answer
81 views

PCB power planes and routing question

Ok this is my first time trying some kind of reverse engineering and I have few experiences in PCB testing so it may be a basic question. Basically I am trying to get the schematics for an 8 channel ...
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2answers
312 views

Were do ground pins on isolation transformer go [closed]

The outputs from transformer have a ground. Is output ground earth ground? Isn't the whole point for those transformers not to provide earth ground potential? Example:
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2answers
105 views

BA3121: Ground loop supression is great however very thin audio quality

Recently I bought a couple of BA3121s to fight the annoying ground loop problems when using several/separated modules (MCUs, BlueTooth, USB etc) in class-d amplifier audio projects and all the modules ...
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2answers
179 views

floating ground

For a big machine (rope shovel) we put a custom electronics board (gps) in an enclosure. It is connected to the cabinet with Power over ethernet (POE). The POE switch is connected to an isolated power ...
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1answer
79 views

Do I have adequate crosstalk and ground loop preventions in place?

I'm moving away from project boards for the first time and was looking to get a bit of feedback before I send my PCB design into production. I'll preface this by saying that the design itself has been ...
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3answers
206 views

Arduino project. USB+external power source - works fine. No USB - everything goes crazy

I have this circuit: It is a simple project - a focus system for a taken lens and anamorphic adaptor. I have three pots. The first one I use as a manipulator. The second is used to get the position ...
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1answer
104 views

eliminate 24v - ground loop that is destroying components

simulate this circuit – Schematic created using CircuitLab I built a suitcase boom box using a cheap BT Rx module and an amplifier module. The BT module is 12 vdc and the amp has an upper ...
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2answers
44 views

Ground loop, Notebook to PC audio daisy chain [closed]

Good evening fellow electro experts, please bear with me. My knowledge about circuits is somewhat basic. I've recently set up an audio chain from the speaker/mic combi jack of my notebook to the ...
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2answers
186 views

Multiboard Grounding In High Frequency

How can ground loop be avoided when connecting two system with same ground. This happen in PC whith SATA cable or PCIe Card with seprated power cable. My System Board: I have two pcb each with a ...
4
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2answers
623 views

Why does radiated emission of a PCB decrease as the frequency of the signal increases?

I was just reading Henry Ott's book "Electromagnetic Compatibility Engineering" and chapter 16.3.3 where he discusses how changing reference planes is detrimental to EMI. Quoting from the book: ...
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1answer
990 views

Ground loop isolation of a USB-powered device

I have a device (Device 1) that is bus-powered via Full-Speed USB and that is drawing up to 400 mA from a laptop. Device 1 has a DAC that can output an analog voltage to another device (Device 2) ...
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2answers
162 views

What is the exact name of this type of transformer?

I know, it is a (1:1) isolation transformer [wrong, see answer], found in some power supplies. However, when I search on this I get all kind of transformers except these. I have searched with the ...
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1answer
182 views

Thermocouple noise causing spurious reading with SSR

I have a thermocouple PID SSR heater as shown, based on the MAX31855 ( datasheet ). I get spurious readings when the arduino is plugged into my laptop, my laptop is plugged in to its charger, and the ...
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2answers
370 views

How safe is parallel wiring two ATX PSUs, if they weren't explicitly sold as dual PSUs?

Pages such as this discuss wiring ATX PSUs in parallel, in what seems to be a sensible manner, with links to various projects showing details. Companies with a decent reputation for ATX PSUs, sell ...
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3answers
558 views

Isolating audio ground between devices

I'm planning a build for a guitar amplifier with 2 stages, the first being a tube pre-amp and the second stage being a solid state amplifier. Both amplifiers will be powered from the same source, a ...
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0answers
115 views

Switch mode power supplies: Floating outputs, ground loops and audio

Since we'll be talking about mains voltages, I'll preface this by saying I'm in the UK, so we have a 240V mains voltage. I built a guitar effects pedal the other day, and promptly fried a friend's ...
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2answers
78 views

Properly earth grounding benchtop supply

A DC benchtop supply is usually ground free, i.e. the negative output is floating wrt earth ground. I used to use HP E3630A which has an additional "Earth Ground" pin and to which I shorted the "-" ...
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398 views

Grounding Neutral Off Grid Solar

Is it recommended to ground the neutral line in an off grid solar system? A nonisolated inverter would be by definition wired this way, right? I believe that in home electrical systems neutral is ...
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2answers
340 views

Grounding audio circuit for RFI immunity

I am trying to determine the best way to ground the following audio circuit for best RF immunity. Right now I'm looking at two options, and am not sure if there's even really much of a difference ...
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1answer
82 views

How to share ground connection between to microcontrollers connected to a PC

I have 2 microcontroller evaluation boards and I am trying to make a I2C communication between them. Both of the boards are connected to the same PC using USB cables. SDA and SCL pins are also ...
2
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1answer
89 views

Use of virtual ground to split ground loops?

So I have a "broadband" signal (DC-5MHz) which I'd like to send over coax cable to two other circuits referenced to the same ground. Simply floating the other two circuits is not an option for ...
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1answer
1k views

Ground return paths versus ground loops in digital PCB routing

I have a two layer PCB, where I do not have the liberty of adding power planes. (However, I potentially could add ground or power pours). My issue is that I am trying to decide whether I should use ...
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1answer
114 views

Ground Plane for different GND types

I am looking for any recommendations or suggestion for Ground Planes for two different grounds I am designing a battery powered device with two voltage sources, 1 coming from the AC wall and other ...
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2answers
71 views

Simple way to isolate video signal

To avoid ground loops I want to isolate several video channels (base-band). I have a video source with 4 channel, they all share the same ground. I'm thinking about some transformer like used in ...
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1answer
666 views

The curse of the ground loop

Sometimes it feels like a ground-loop is inevitable. Please follow along the following thought-experiment. It would be wonderful if you could provide solutions to the issue described. Imagine a board ...
2
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1answer
75 views

Which one of these shielded scenarios is correct?

I have a system were both the signal generated and the sensing equipment is sharing the same ground. Which one of these shield terminations scenarios is correct? (if any). I searched the internet for ...
2
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0answers
651 views

Why do some audio amplifiers connect the power ground to the signal ground?

Trying to add a MIDI synthesizer & speakers to a keyboard here. Here's the schematic: simulate this circuit – Schematic created using CircuitLab But I was getting annoying crackling and ...
1
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3answers
390 views

Reduced gain with ground loop isolation with car aux head unit

How to suppress ground loop hum without reducing audio gain? I added an aux input to my car's factory head unit by soldering wires onto pin 4 (right channel) and pin 33 (left channel) of the M62490FP ...
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1answer
157 views

Closing loops or not? - supply lines on a PCB

When routing a Gnd line, I wonder if it's best to keep loops open, like so:   or to close the loop, like so: I could think of some arguments in favor of closing the loop: PRO Looping arguments:...
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1answer
179 views

Cable shielding groundloop

I am trying to connect a encoder to a motor controller which runs very close to the motor that it controls (30+ amps). Due to the risk of high EMI of the motor inducing on the encoder signals, we send ...
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3answers
430 views

Connect signal ground to safety ground?

We are designing a product which has to meet EMC directives. It consists of metal backplate folded into a chasis (the front is open). on the backcover there is a SMPS mounted. and on top of this we ...