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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60 views

Buck Converter PCB Planes

I have a question about PCB copper planes with buck converters. For reference, I'm using the LM2673/LM2679. The parts are identical in layout, utilizing the DDPAK/TO-263-7 with the PCB tab being ...
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35 views

Isolated step-down module for powering a Raspberry Pi from a speaker's 12V supply avoiding ground loop and interference

I have an older speaker with an iPod dock that I would like to extend with a Raspberry Pi as a streaming music player. At first, I tried powering the RPi from the dock connector with a Micro USB ...
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3answers
52 views

Short between GND of Arduino and AC powered circuit

Upper left corner is a simple AC powered circuit that can supply 15mA of DC current. Lower left is an Arduino connected via USB to desktop computer. The meter shows a voltage of 1.58V between the ...
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2answers
55 views

Avoiding ground loops with common-ground DAQ

I am looking to acquire data from several sensors on a machine, each of which are part of a control system featuring several grounds linked at a single central point. I need each sensor's signal at ...
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1answer
35 views

Analog sensor signal isolation for ADC/DAQ

I am looking for the simplest way of sampling an analog sensor signal in an existing system while avoiding ground loops (say 20kHz maximum frequency). The sensor is a 5V supply with 0-5V return signal....
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1answer
29 views

Should I use a differential mode amplifier for mixing up to four stereo signals together?

I'm designing (probably over-designing, but I want the experience) a four-input, four-output, stereo mixing setup for my PC setup, but I'm concerned that just tying all the ground lines from that many ...
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48 views

Can I connect a PSU to the Ramps 1.6+ and the USB to Arduino at the same time?

I just want to connect the Ramps to the power supply unit and upload the Marlin firmware to the Arduino. I found three possible outcomes 1. Problem I found one person here who says that we should ...
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1answer
27 views

Timebase Ground-Loops - why place the isolation transformer at the input instead of the output?

In the course of investigating the construction of a home-made 10 MHz lab frequency reference I wondered if the output from such a reference should be isolated. I came across a small article about ...
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1answer
41 views

Reading UART from device that has floating ground

I am powering an ESP32 over a less-than-ideal power line, that has 4 Ohms of resistance. In order for 5V to arrive at the device, I apply 7V to the power line, such that when 250mA of current are ...
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1answer
75 views

Is it OK to have a connection between 0 and PE on a DC device?

I have a device meant to be used inside electrical cabinets. It has a metal casing and is powered by 24V DC. It has three power connectors: 24V, 0V and PE. I was surprised to find out that 0V and PE ...
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52 views

How to measure isolation resistance between floating ground levels?

There a two isolated ground pins on an isolated dc-dc converter . What method is used for measuring isolation resistance between input side ground level and floating (output side) ground level?
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1answer
154 views

Shielded Ethernet Cables in Office Buildings - Ground Loops?

I have a question related to shielding and grounding of ethernet cabling in industrial environments, offices and datacentres. What I assumed as correct so far (please correct me if I’m wrong): In ...
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2answers
85 views

Avoiding ground loops with multiple coax cables

I have to connect two devices with multiple coax cables each carring a signal that has frequency components ranging from DC to a few GHz. I don't know how to avoid ground loops with this type of ...
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5answers
319 views

Waves on raspberrypi camera feed, Ground loops? electrical interference?

I run a video recorder in a vehicle built on Jetson Nano (Very Similar to raspberry pi). It runs on 5V . The vehicle has a 24V power supply. I power the video recorder with an automotive-grade 24V to ...
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1answer
93 views

Ground loop problem in op amp circuit

I am having problem with a few millivolts of ground loop in my single channel amplifier circuit when I ground the input (pin 1 on socket, - input of op amp). I am using INA121 instrumentation ...
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1answer
98 views

AGND and GND - Grounding in Schematics

I have seen a few electrical schematics where there are separate symbols for grounds. "Agnd" and "Gnd" Can someone help me understand what are the differences between those two and where to use "Agnd"...
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44 views

Voltage spikes caused by stray wire

I recently had a PCB designed which has several analog, digital, and power elements. The board is powered by 24Vdc which is stepped down using an LDO to 3.3V and 5V. These voltages are used to power ...
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185 views

Confusion about GND and PGND

In a digital circuit like a cell phone. If a switching ic has it’s reference point as PGND, separate from the main GND (4v Main vcc coming from battery), but they’re tied together, then What exactly ...
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2answers
106 views

Ground loop- Why would current flow between 2 earth grounds when signal return path offers the least impedance?

Lets say I have 2 ICs- C1 and C2 acting as driver and receiver for the digital signal. The signal is transmitted through a conductor/cable ( 2 wires) as shown below. I have 2 doubts 1. What would be ...
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1answer
148 views

pcb board to board connector dealing with ground current

Recently I am designing 2 separate pcb. one of them will be controller with low current signal paths and the other one will have mosfets to control high currents(about 10A). I am thinking of ...
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1answer
243 views

Do I need to tie every ground pins of esp32 wroom 32 to the ground

Which is the proper way of grounding for the module To avoid the ground loop I think fig. A is the best.
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1answer
166 views

Ground loops with S/FTP Cat6 Ethernet cables

I have an issue with an Ethernet cable causing a ground loop between my router and a raspberry pi, causing noise on the ground of the DC power of the Raspberry. The router/power supply of the RPi are ...
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2answers
64 views

Measuring voltages from different sources sharing Common ground that might differ slightly

I have a design with resistor dividers and low pass RC filters dropping down 0-32V to ADC range of 0-1.8V. With multiple channels, I attempt to measure voltages from different voltage sources on a ...
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1answer
68 views

Optimum placement, PCB routing for bypass/decoupling capacitors and ground loops

I've seen various answers regarding routing of decaps, wondering which method is optimum for better power distribution and noise immunity: Another question is, will this routing cause ground loops? I ...
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2answers
210 views

Criticism of my differential pH probe design

I finished and tested with buffers this little differential pH probe on a perfboard, it works, 3 points calibration is linear. The ground electrode is a stainless steel rod wired to the GND of the ...
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5answers
1k views

Isolated audio without a transformer

I'm putting together a guitar pedal for splitting the signal to two different amps. One of the features I want to put in is a 'ground-lift'; isolating the signal to avoid ground loops between the two ...
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1answer
105 views

LED Strips - Data Noise Over Long Distance Between Controller and First Strip

Please refer to the above picture. The black line is the ground wire and the green line is the wire carrying data. First Question In regards to data noise/interference, can the output ground wire ...
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1answer
63 views

Excessive Ground-Loop/Discontinuity?

I am designing PCB2 & PCB3 but PCB1 & PCB4 are set in stone. My constraints are as follows: 1) The PMIC must be the 1st device to become alive. 2) As much as I would love to, I cannot use the ...
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1answer
136 views

USB ground loop isolation for multiple devices

I have a use case where I use JTAG debugger connected to the circuit under test. Circuit is powered from a desk PSU and measured via desk MSO. This would normally create a ground loop, so I use an USB ...
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1answer
116 views

Noise when amplifier and chromecast share a power supply

simulate this circuit – Schematic created using CircuitLab I want to power a chromecast and an amplifier from the same power supply. When the dc/dc converter is powered by a separate power ...
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1answer
108 views

Multiple ground planes, single point ground, and a level shifter

I'm using a level shifter to go from 3.3V to 5V (digital/analog). According to the datasheet, if I put 1 ground on the left side of the IC and the other on the right, it would tie the grounds together ...
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1answer
53 views

Ground with different power supply and microcontroller

I'am encountering problems of ground loops with the scheme presented in the attached figure. In particular, the analog output seems influenced by the analog input signal, since currents loops I ...
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1answer
150 views

Shield ground to metal body or signal ground?

I have a question about grounding. I will have two short shielded cables with signal wires inside, located at the top of a tower. The cables have a grounding wire inside shorted to their foil shields ...
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2answers
383 views

Isolating an audio line connection with two capacitors

I've looked at several questions, such as: Isolating audio ground between devices I want to connect an input and output audio line signal of two different devices. The earth potential of their audio ...
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0answers
70 views

Reading Digital and Analog Signal from Different Sources with Arduino

I am using an Arduino to read signals from 2 different devices. (This is an automotive project so all 3 are powered by the 12v battery of the car). The signal from one of the devices is a digital ...
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0answers
93 views

Why use opto-isolation in this way?

I'm synchronizing two FLIR cameras and FLIR's use of opto-isolation in this document doesn't make sense to me. Could someone explain the benefits of using opto-couplers as FLIR describes? The two ...
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3answers
185 views

Question regarding ground when using teensy to control a mosfet switch

Despite the fact that I'm pretty new to electronics I'm working on a quite ambitious project which is basically a USB-Midi Controller attached to different devices that send different signals. The ...
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1answer
67 views

How do you monitor communications on a positive-grounded device from a negative-grounded desktop?

I have a need to read the signals being sent between two boards in a lighting fixture. In preparing to do this I have read much about the chips, RS485, and analysers/decoders that are out there. I am ...
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2answers
85 views

Not Understanding Grounding in an Electrical Circuit

This might be a stupid question but i am just a little confused about grounding/earthing. Specifically for example in a home when some electrical appliance faults, the current will go to ground since ...
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80 views

Grounding Multiple Devices

I am designing a motor controller with an Arudino, UBEC, and ESC. The Arduino will control Servo Motors and Brushless Motors. I want to make sure I understand how to hook up all the devices to avoid ...
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3answers
109 views

Sensor damage, ground loop or something else?

We are testing an capacitive fuel level sensor in field. Its mounted on top of a heavy construction vehicle (colmar) with a 24v battery system. Our sensor runs for few weeks and damages. Every time a ...
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1answer
74 views

How can the earth ground loop be modelled for this case?

Below is a single ended system where the source and and the receiver are both earth grounded forming a ground loop through the earth which has a resistance of Rearth = 1 Ohm. simulate this circuit &...
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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
116 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
64 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
156 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
180 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
1k 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
69 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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3answers
592 views

Is star grounding sources necessary for this data acquisition system?

Several single ended output and PSU powered transducers are tens of meters apart from each other outputting 0 to 10V DC like voltages. Some are temperature transducers some are force transducers ect....