Problems related to the connection of circuits to ground or earth references. Can affect safety, accuracy, reliability and interfacing.

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dsPICDEM MCHV-2 Development Board motor connection

I have dsPICDEM MCHV-2 Development Board and three phase induction motor. I don't know how to connect the motor to the development board. I have connected three lead wires of the motor to the three ...
4
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1answer
65 views

How can I ensure low-resistance ground contacts to an aluminum enclosure?

I am building an electronics project with an aluminum enclosure. I need to ground it—and very well—for human safety. (The system handles 300 A of current, and I want to be sure that if there is an ...
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2answers
61 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 ...
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1answer
48 views

Connecting to oscilloscope ground reduces noise significantly? [on hold]

I designed an isolated ADC system. The system is noise when left alone. However, if I connect oscilloscope probe's ground to ADC system's ground, the noise improves significantly. Is my board ...
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2answers
57 views

Why should we couple AGND and DGND?

we can see the connection at the right hand side between the DGND and AGND! according to my course text,"the real electronic ground of the system is where the point AGND and DGND are coupled." but ...
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49 views

Computer motherboard grounding, is it possible to short my motherboard doing this?

Some information: I essentially have a custom created case that I believe is sheet aluminum. and have placed a mini itx mobo inside. Since the case is very small, I wanted to buy small standoffs. ...
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1answer
100 views

Do DC current can be earthed? [closed]

If I take a 12 V battery and connected its (+) terminal with the (+) wire of a load and connected the negative wire from the load to the ground (earthing). I have heard that earthing absorbs current ...
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2answers
73 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
86 views

GND in a DC circuit with circuit board

I wonder a question. Let's say I use a circuit board in a project (the left hand side on image below, not the Verabod), and I want to solder a circuit on it. For example, I want to use the circuit ...
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29 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 ...
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1answer
65 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 ...
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1answer
69 views

how to differentiate the gnd audio to gnd of battery?

i'm new to the forum. I have some problem to Connect this device with one single battery. I think the problem is on the connection of the max4466 electret. It has a common ground and it make me ...
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2answers
96 views

What are reasons for NOT connecting exposed pad (EP/thermal pad) to ground?

For what reasons would a manufacturer suggest that the thermal pad should NOT be connected to ground? See link and snippet from a Nordic datasheet. ...
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3answers
386 views

Why an electrician wiring error could make a PC's USB shield be at 120V when it should be grounded

I almost had a serious electrical accident last week when I was trying to use an oscilloscope to test out a circuit a student had built. I had the scope plugged into a floor outlet, and the circuit ...
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1answer
67 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 ...
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2answers
104 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 ...
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2answers
68 views

where the extra electricy in earthing goes? [closed]

excuse me I'm newbie in electricity , can you please explain how electric will go through one cable that is connected to an earthing rod that is not connected to the circuit or the system being ...
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77 views

Is it possible a zigzag grounding transformers made from single-phase 220:12 transformers?

We have 20 transformers 220:12V rated 2 A in stock. We want to make an experimental zigzag grounding transformer to reduce the third harmonic current injection from single-phases, slightly unbalanced, ...
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1answer
85 views

How to ground the below circuit when I use USB?

I am constructing the circuit given below: The problem, however, is that when I connect the electrodes to my skin, I get a mild shock. I am powering the Arduino using an USB cable. I connected the ...
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2answers
56 views

How do I connect the virtual ground as shown below

This is a circuit for EEG. How do I make the connections labelled as Virtual Ground? Also, how do I connect the 1M trim pot in the top right?
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1answer
88 views

Are Faston tabs safe for earth grounding?

I am having a discussion with coworkers about sufficient grounding to a chassis... my opinion is that a toothed ring terminal in contact with bare metal is required, e.g. Molex 19074-0025, so that the ...
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1answer
57 views

Ground isolation

I am looking at ways to isolate my board and supply ground. I am feeding my board with a 40V dc power source. Now, the ground return of my board should not be connected to the battery return is the ...
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1answer
26 views

about grounding on different circuit board

I got a STM32 development board, which is used to control another board for DDS output. The STM32 board send digital signal (TTL) for output control on the DDS chips. The STM32 board and the DDS board ...
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755 views

How do I decouple ground planes?

I have designed and built a motor controller circuit. The circuit has a microcontroller on which gets commands from a PC using an FT232R. Currently the FT232R is powered from the board's +5V supply. ...
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1answer
49 views

grounding measurement methods

As long as I know the accepted methods for measuring the resistivity of electric grounding grids, once they are built, for any kind of building (in cities, at industrial level, transmission towers, ...
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74 views

FDNR instability

Can anybody advise me, I have made many attempts to make a practical FDNR circuit, but it is always very unstable with lots of RF oscillation. I am trying to make and audio filter, that is the ...
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2answers
131 views

The back of a pot used as a signal ground, in a grounded chassis design; how reliable?

This question relates to those large pots with solder terminals that are still used in electric guitars; they used to be common in metal-chassis radios, amps, TV, as volume and tone controls. It was ...
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63 views

Is it always OK to directly connect grounds of different voltage sources?

In my specific case, I have an arduino and a servo motor. Arduino is powered from PC via USB (5V). Servo is powered from a separate AC-DC adapter because it needs more current. In order to control ...
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49 views

Static Discharge on Metal Enclosure for Tablet causes restarts

The setup I currently have is a Aluminum enclosure for an Android Tablet. Inside the enclosure, a shielded USB cable is routed into the micro USB port and out through a small opening. This cable is ...
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5k views

Why don't we use neutral wire for to ground devices and earth wire for closing the circuit?

I know that the neutral point of a distribution transformer is connected to the grounding (earthing) wire so I thing they are the same. Can I use the neutral wire for protection purpose and connect ...
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66 views

Connecting Vcc pin to a logic gate

I have a sonar sensor which has 4 pins and may be due to a bug in my code, they are freezing in a few seconds after functioning. I found out if I reconnect the Vcc pin, they start working and yeah ...
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2answers
244 views

Arduino: How to read sensor without common ground?

I want to analogRead() the voltage coming from a plasma cutter and serial print it. The problem is that the serial communication between my laptop and Arduino are breaking as soon as i turn on ...
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2answers
811 views

How to wire 3 phase motor to VFD

I am trying to wire a new motor to a variable frequency drive (VFD) and having some trouble figuring out how to wire the motor to the VFD. The motor is a 1 HP, 3-phase, 208-230/460 volts, and I'm ...
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51 views

How to check the grounding of rack shelf for ESD

Can anyone suggest how to check the grounding of the Metal Rack Shelf for Discharging Static Electricity? I have an Earth tester with three terminals. Is it possible to conduct the test by using ...
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1answer
79 views

PCB plane cuts for audio paths in mixed-signal device

I am working with the TLV320AIC3204 32-bit audio codec. The codec has three inputs and two outputs. While I was designing my own test PCB, I noticed on TI's evaluation board (on page 33) that they ...
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1answer
49 views

How to place decoupling Capacitors in a star ground design?

I am in the process of routing a star-grounded amplifier pcb and wondered on how to connect the decoupling capacitors. As I see it I have two choices: Connect the ground of the capacitors directly ...
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2answers
81 views

Connecting Analog GND and Digital GND of ADC

I'm trying to make a simple line tracing robot, however I couldn't figure out how to connect AGND and DGND of A/D converter(MCP3208) on a simple perfboard design. I need some guidance how to smooth ...
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1answer
120 views

How can one use the earth as a second wire?

I read recently that the earth can be used as a wire to save wiring costs. My understanding of how this works is that a power source, say a battery, separates charge, creating electrons on one side ...
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2answers
64 views

Mounting Hole Connected to Ground Through Capacitor

I've inherited several board designs where each of the four [plated through] mounting holes are connected to the board's ground plane through a capacitor [1000pf, 1KV]. I can understand why you might ...
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229 views

How to isolate two ground signals?

I'm have grounding problems (80% sure of it). I have an MPU6050(gyro sensor which works on 3.3V) which is powered by the Arduino's 3.3V pin and SCA,SCL,INT pins are used with the I2C bus of the ...
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1answer
64 views

Is this ground plane correct?

I am trying to improve my grounding skills This is a RJ45 connector on one side, a signal transformer, and a pin header on the other side (this is a prototype, and i am splitting the design in parts ...
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1answer
79 views

common mode ground

My doubt pertains to a certain document/app note about common mode and differential grounds- Link1 and Link2. What I read about common mode noise is that it is a noise generated on all signal lines ...
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3answers
484 views

Is a ground/common needed for proper CAN bus communication?

Since CAN Bus is a differential signalling system, what is the significance of GND/COM signal? Can I get by without it? I've got a very simple 2-node system that has some weird happenings going on. ...
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4answers
98 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 ...
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1answer
53 views

Grounding of a PCB that communicates with a PC via USB or RS232

I have a PCB with an atmega8, communicating with a PC. The signal from TX and RX pins is level-shifted through a MAX232 to standard serial port level, then converted via serial-to-USB commercial ...
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1answer
104 views

Effects of unearthed PSU and shielding on audio 50Hz hum

I am trying to get a good understanding on sources of 50 Hz “ground hum” interference in audio equipment and good practices for shielding and grounding by making hum on purpose and taking steps to ...
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4answers
320 views

Tape recorder head has only 2 pins, which one is for grounding?

I am trying to make my own cassette adapter that will help me play my music on my iPod through my car stereo system that supports only cassettes. For that I've bought a 3.5mm earphone jack and a ...
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69 views

ESD - SMA connector

Suppose I have PCB in metal chassis with 2 SMA connectors mounted on it. Let's say they are used for GSM and GPS. How to protect against ESD and successfully pas FCC/CE? I couldn't find any TVS ...
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1answer
56 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 ...
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596 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 ...