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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2
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4answers
76 views

Multiple Ground Referenced Sensors on Single Floating Supply

Some background: I'm designing an industrial control board with isolated analog and digital IO. The hope is for it to be pretty foolproof, such that you could connect any 4-20 mA or 0-5V sensor with ...
1
vote
1answer
50 views

Where do the return currents go for a MCU with multiple Vdd and grounds?

I am reading this article on mixed signal design: https://www.maximintegrated.com/en/app-notes/index.mvp/id/5450 When signals have really high speed, the return current will tend to follow right ...
5
votes
4answers
434 views

For Multiple ADC circuits PCB layout grounding, why is “single point ground” important?

I am reading this article from Maxim on mixed-signal circuits grounding: https://www.maximintegrated.com/en/app-notes/index.mvp/id/5450 Everything makes sense to me until I read the "Grounding ...
0
votes
1answer
85 views

Arduino with L298N Motor Driver and external Power

I would like to control a slave clock which requires 24v applied for approx 1/2 second in alternating directions once every minute and have bought a Arduino Uno to control the pulses. The Arduino is ...
0
votes
2answers
103 views

Self-powered USB device isolation

I'm designing a USB device (a 3D printer board) which I want to power from an old PC power supply and use the USB only for communication. My understanding is that both the power supply and my PC are ...
1
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2answers
169 views

Ground Loop Explained

I need somebody to explain properly how the ground loop works, especially if this happens when is only a DC circuit like a power supply for a motor and a coaxial cable which carries a PAL signal. ...
5
votes
2answers
167 views

How on earth shall I design the ground planes for mixed signal circuits, split or not?

Our circuit is like following: There are four layers, including top, power, ground and bottom. My way of grounding: I follow the instruction by Maxim: ...
2
votes
1answer
77 views

Ground loop between Pc and projector via VGA cable

Our hall has a projector hooked up to a PC via a VGA cable but we're seeing horizontal bars on the projector image when we turn on the lights in the hall. I'm think it's a ground loop problem. I'm ...
0
votes
2answers
68 views

Ground loop Isolation transformer, alternative?

Most of those transformers are a bit costly in my region(India). is there any alternative solution that can be employed. Application in audio amp. I was thinking maybe use a step-down and step-up ...
0
votes
1answer
89 views

Minor electric shocks from touching appliances, loose ground? [closed]

I get minor electric shocks when handling everyday home appliances barefoot. These appliances include laptop when the charger is connected and fridge etc. Can the reason for this be loose ground ...
0
votes
0answers
70 views

LCD Flickering when Shielding is not Connected to Ground

I got myself one of these LC-Displays: http://www.sainsmart.com/sainsmart-hdmi-vga-digital-9-9-inch-1024x600-lcd-driver-board-for-raspberry-pi.html It's a barebone LCD setup with just the components ...
1
vote
5answers
107 views

Welding Thermocouple to Test Sample

I have a 3mm copper test sample that is going to get heated up, and I would like to know how hot it is actually getting. Previously, we have just held the thermocouple close to the sample, but we are ...
0
votes
1answer
142 views

Loops in ground planes

Working on a PCB layout and just did some ground plane pour. From working with tube amplifier designs I know that a good star shaped ground design helps a lot to keep hum out of the circuit. Ground ...
-1
votes
2answers
225 views

unbalanced audio - shielding and ground loop for 2 ch

I have a 3 conductor wire that are all wrapped in a foil shield with wire conductor, for a total of 4 wires. I am connecting the 3 inside wires to audio left, right, and ground. This is an unbalanced ...
-1
votes
1answer
54 views

PWM Return Problem

A controller send pwm signal with 2 wires 1- PWM 2- PWM Return But servo motor has 1 input pin. So is it correct to use servo supply return (28v Gnd)or servo chassis input for controller pwm return ...
1
vote
3answers
168 views

How safely to send signal between logic and higher current pcb?

I'm designing a PCB with 4 FETs. These are driven in the same board by totem pole drivers, and their load are about 5A total. I am using PWM at 1000Hz. The signal comes from a logic IC in another ...
0
votes
1answer
339 views

Arduino/Netduino: connecting a second power supply's ground to GND pin

I'm planning to play around with an addressable LED strip and a Netduino, and having read some tutorials I've learned that I will need an external power supply to provide enough current to the LEDs. ...
1
vote
3answers
1k views

Ground Loop? Noise from 12v to 5v converter manifest in bluetooth audio source

I've created a custom, bluetooth audio harness for my Jeep WJ using off the shelf parts. Amp - Clarion XC1410 Converter - 12v to 5v buck converter Bluetooth Audio - Logitech Wireless Speaker Adapter ...
0
votes
2answers
313 views

Oscilloscope measuring of PMT in photon counting mode

I have a setup as drawn below: DC source of 15V connected to high voltage (HV) source of 1500V connected to photomultiplier tube Hamamatsu, R1-R3 are resistors builtin the socket of PMT (there are ...
5
votes
3answers
654 views

Does a Connector With Multiple GND Pins Make a GND Loop?

There are some cable standards that have multiple GND pins on the connector proper. A good example of this is the SATA connector (it has 3 of them). In reality, each GND pin has a slightly ...
8
votes
1answer
837 views

Why is this resistor connected between connector shield and ground?

I was looking over my raspberry pi model B and I noticed a resistor between the USB power connector shield and ground. I've noticed this on many PCB designs with much larger packaged resistors ...
1
vote
2answers
88 views

Are there other ways in which 60Hz noise can get into your system?

Are there are other ways in which 60hz can get into a system other than ground loop ?
5
votes
2answers
851 views

Single point vs Ground plane, in audio OP AMP PCB layouts

Recently I had posted a seemingly innocent question on another forum. I was trying to keep a small and relatively simple circuit down to a 2 layer board and was asking about the shielding merits of a ...
1
vote
1answer
103 views

Can we consider that ethernet or RS-232 (RS-485) networks have no ground connection between the two ends of each cable?

This is for a huge home theater. I have a power transformer that converts 380VAC between two legs of a 3-phase power system down to 230VAC, with a center-tap of the secondary being our "neutral" for ...
2
votes
1answer
244 views

DIY wifi radio radio NOISE!

I am building a mono, internet enabled, WiFi radio and I have a problem. I am running into what I believe may be a grounding issue. When I turn the system on, I hear all kinds of noise coming from ...
0
votes
1answer
279 views

Should I worry about ground loop in power supply circuit for 3G modem or WiFi?

Can someone explain clearly what is ground loop and when we should worry about it? Shall I worry about it when I connect two USB wires in parallel to deliver power to my 3G modem? I have something ...
5
votes
5answers
419 views

Properly grounding 2 MCUs using I2C

I'm building a mechatronic system that consists of 1)XY Gantry controlled with PIC32 and a DIY motor shield and 2)control box with PIC24 three potentiometers + room for expansion, typically located ...
1
vote
0answers
194 views

Ground loops on single trace in the middle of a ground plane

I'm trying to optimize the layout of a MAX1979 TEC driver on a double sided PCB. Is the placement of single, small traces in the middle of a ground place, as seen below on the bottom side of the ...
0
votes
1answer
97 views

Why a ground loop a problem, not a ground plane(patch attena)?

The question is as the title says: I see various material saying using a solid ground plane. Why would not that be a problem, since a solid ground plane could be a patch antenna?
3
votes
3answers
309 views

loop area and EMI

I always hear something like "reduce the loop area" when reading materials on EMI reduction. Why we need to minimize the loop area? I have two guesses: Smaller loop area will influence less signal ...
2
votes
3answers
571 views

Ground loop when measuring in process pH

I have been experiencing a very difficult to solve ground loop problem with my pH measuring system. My basic setup is a standard pH electrode running through an op-amp to an ADC which communicates ...
1
vote
1answer
131 views

What is this Circuit's function? Does it involve Isolation?

My question is: Does this circuit isolate the "X Volts" lines from ground (1) If not, how should I implement an opto-coupler to provide isolation between the data lines ("X Volts") and ground? ...
2
votes
1answer
783 views

How does a first-timer set up a correctly-grounded workbench / work-station?

I'm new here, and new to electronics in general. (for the most part … my [awesome] father had me building some simple robot-kits with him when I was a kiddo, but I'm getting into it “4srs” for the ...
1
vote
2answers
383 views

RS485 + Power over twisted pairs, still need isolation?

I need to communicate with a piece of hardware on an elevator car. I have a few twisted copper pairs available, but it's not CAT5, so Ethernet is out. Instead I'd like to use RS485. I've been ...
4
votes
1answer
251 views

Wiring multi node devices with i2c

I wanted to confirm that my approach is correct for wiring multiple devices together communicating over I2C when each node is utilizing DC\DC converters. Should I be including a ground connection over ...
2
votes
2answers
386 views

Ground Loop for balanced connection

Different articles and tutorials covers somewhat contradictory information about ground loop. For a balanced connection (differential), the return path is the other differential pair, however ...
3
votes
1answer
291 views

Proper power design for a USB device

I'm designing a USB device that I want to be powered eintirely from a wall wart and have a couple questions concerning the power connections and ground loops. 1) If I connect the USB GND pin to ...
0
votes
1answer
1k views

How can I reduce hum & pop from simple amp setup?

I am building a bluetooth speaker and am encountering two issues. Here is my setup so far: When turned on, it gives two very loud POPS before working normally. Is there a simple way of delaying the ...
6
votes
1answer
541 views

How to avoid a ground loop between pcbs

There is an enclosure with 2 separate pcbs. Pcb A amplifies a mV level signal (10Hz to 100kHz) coming from an external sensor. The amplified analog signal is sent to pcb B, which digitizes it and ...
3
votes
2answers
2k views

Can I use ferrites for the ground connections?

I may have an issue with conducted EMI through the ground connections between devices in a system. There is specifically a device which clearly creates noise on the measured signal from another ...
2
votes
1answer
227 views

What is return current of crystal oscillator?

I belive that every signal on the PCB has its return current. One layout hint for crystal oscillator is that "The ground connection for the load capacitors should be short and avoid the return ...
3
votes
1answer
342 views

Inter-PCB Ground Loops

I have designed a mezzanine PCB that will sit on top of a main PCB connected via two connectors on either end of the mezzanine PCB. If I connect the grounds on at both connectors (And thus at both ...
4
votes
4answers
3k views

Ground loop problem with Power over Ethernet

I am trying to build a weather station, powered using Power over Ethernet. Originally I planned to use a Nanode as the microcontroller, but since the Raspberry Pi is so cheap, I decided it was much ...
0
votes
1answer
208 views

SMPS power supply shows strange AC voltage output

Hi I have been using a simple laptop power adapter (15V) for my electronic lab-works. And today I'm troubleshooting some RF circuits, and I found a little guilt about ground loops, So I check ...
0
votes
2answers
243 views

Should old electronics be polarized?

On old electronics that don't have a polarized power cord, what would be the benefits of adding a 2.2Mohm resistor from one side of the a/c to the chassis and switching out to a polarized cord ...
9
votes
1answer
2k views

To “ground fill”or not to “ground fill”?

I have been reading up on the EMI issues in Electromagnetic Compatibility Engineering by Henry Ott. (wonderful book btw). One of the topics "PCB Layout and Stackup" (aka Ch 16) there is section about ...
4
votes
2answers
3k views

Power supply noise in audio

I have what is surely a classic problem with regard to power supply switching noise and audio but I am unable to sort myth from reality with regard to what I found so far on the topic. Setup: I ...
1
vote
2answers
1k views

USB port and bench power supply ground difference

So I recently coughed up the $250 for a semi decent bench power supply, the thing that got me though is when powering a circuit from this unit and connecting the BusPirate via USB is that the ground ...
9
votes
4answers
4k views

Why we use ground

I have been wondering this for a while, so I did some digging, and as usual, wikipedia was the most illuminative. It looks like the telegraph was the first time ground was introduced to complete a ...
9
votes
2answers
783 views

Shielding and Ground loops

I have various pieces of equipment that all need to be connected to GND (Chassis GND). The issue I'm having is that I'm connecting an ADC card inside a computer through a metal box with custom ...