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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2answers
36 views

Ground Loop RS232 between PC and Breadboard

I have a microcontroller circuit on a breadboard that I want to to connect to my PC via a RS-232 interface through a MAX232 IC. The breadboard is connected to an external power supply. One of the ...
0
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1answer
62 views

Using an earthed function generator with an earthed oscilloscope and ground loops

I have a function generator and I noticed that its DC GND is internally wired to its earth pin. Similarly I have an oscilloscope and I noticed that its DC GND is also internally wired to its earth ...
0
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2answers
80 views

How do you get rid of hum in audio?

I built a circuit for a simple amplifier that can use both bluetooth or a 3.5mm connector. The problem is that I am getting noise when I use the bluetooth module. There is no noise when I use the ...
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vote
1answer
39 views

DC Adapter - AC Potential to Earth

With a switching DC wall adapter, when I measure AC rms voltage from either of the output wires to earth ground, what am I actually measuring and is this a controllable spec of a wall adapter? I am ...
0
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1answer
40 views

External Power Supply Grounding Scheme

The following are two possible grounding schemes for a sensitive instrument that contains high gain analog circuits and potentially noisey digital circuits: This circuit is connected to an external ...
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0answers
33 views

System not working as expected - resistance measurement

I found a problem while measuring the resistance from PCB1. When both the FETs are enabled on System 1,the resistance is measured. PCB1 is powered from USB port 1 and system 1 is powered from ac-dc ...
3
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2answers
69 views

How to stay well grounded?

After some read about ground plane breaks and inductor loops, now I am totally confused about how to design good PCBs. I made a small example of a two layer PCB. Blue is the big ground place. Red are ...
4
votes
2answers
71 views

How does Hybrid Ground Works?

The text that is above the figure is from my textbook and i am having difficulty to understand what it is trying to say because it's not in detail!! why only remove high frequency and prevent low ...
6
votes
2answers
82 views

What constitutes a “sufficient” ground?

Electricity novice here. Thanks for reading! I have a 3000 watt DC to AC inverter attached to a 12V battery bank. The inverter has "DC ground lug" on the exterior of the inverter's case which the ...
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2answers
78 views

Grounding options between three PCB's

I have a PCB (let's call it PCB #1) that has a Li-ion battery as its power source, sourcing 12V to 17V. The power from the battery is used to step down to 6V using a buck converter on PCB #1. A cable ...
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0answers
32 views

Power planes, virtual grounds, and ground loops in mixed signal 4 layer pcb

I'm a hobbyist and really need some help with a project I've been working on. I have a four layer PCB with analogue and digital parts. The ground power plane is split between them but with a join ...
0
votes
1answer
66 views

Ground potential not at zero in 30y old apartment

I am living in an about 30 years old apartment in China. Sometimes when I am touching my Mac Book (aluminium case) I would get little electric shocks. I measured the voltage between my Mac Book case ...
0
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1answer
46 views

DC LVDT Excitation voltage to NI CompactDAQ

I am currently working on getting reading from an LVDT for a project the present model is the DC LVDT model Omega LD620-25 As per it's datasheet the model requires an excitation voltage of 10-30V and ...
4
votes
1answer
71 views

Grounding Scheme for Signal + Power

Background I am working on a project which requires a both digital and analogue signals along with power and biases to be connected between two devices over roughly 1 metre is quite a harsh (magnetic ...
4
votes
2answers
112 views

Avoiding ground loops

I'm a little stumped by how to avoid ground loops. I need to connect to a mostly analog external component that requires VCC_12V, VCC_5V, VCC_3V3, VCC_N7V (\$-7.0V\$) and GND. I assume the external ...
0
votes
4answers
115 views

Remove ground loop hum by 180º phase shift?

I have a homebuilt subwoofer for my surround sound audio system. 400W constant, 900W peak. However, there appears to be an AC hum on the input line, and it becomes especially noticeable when I ...
2
votes
4answers
103 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
60 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
653 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 ...
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1answer
225 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
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2answers
130 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
276 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
242 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
136 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
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2answers
107 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
93 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 ...
1
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5answers
123 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
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1answer
172 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 ...
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votes
2answers
274 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
58 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
177 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
411 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
2k 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 ...
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2answers
399 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
700 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 ...
9
votes
1answer
927 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 ...
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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 ?
6
votes
2answers
1k 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
111 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
266 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
311 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
433 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
267 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
107 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
377 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
650 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
137 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
1k 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
427 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
280 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 ...