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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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1answer
75 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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58 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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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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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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93 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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60 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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131 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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61 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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52 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
54 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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183 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
68 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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59 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
75 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
72 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
80 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
51 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
101 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
353 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
57 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
85 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
130 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
60 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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82 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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64 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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96 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
70 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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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
61 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
138 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
161 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
709 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
57 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
528 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....
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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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166 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
2k 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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1answer
576 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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1answer
128 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
489 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
103 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
120 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
201 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
88 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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3k 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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310 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
356 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
177 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 ...