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Questions tagged [grounding]

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

6
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1answer
5k views

Analog & Power Ground Planes Doubts

Working on a new board, I have to face some requirements to ensure the performance of the whole system once is manufactured. PCB is a 4-layer one, and it has both analog and digital components. But ...
100
votes
6answers
42k views

Should chassis ground be attached to digital ground?

I'm working on a PCB that has shielded RJ45 (ethernet), RS232, and USB connectors, and is powered by a 12V AC/DC brick power adapter (I do the 5V and 3.3V step down on board). The entire design is ...
32
votes
5answers
20k 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 think they are the same. Can I use the neutral wire for protecting metal-cased electric ...
38
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2answers
30k views

Competing PCB Crystal layout recommendations

This is related to this question: How's my crystal oscillator layout? I'm trying to layout a 12MHz crystal for a micro controller. I've been reading through several recommendations specifically for ...
58
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9answers
30k views

Why on earth are o-scopes earth referenced?

Thinking about it: You would never find a "Grounded" multimeter as robust and useful if a path to ground through the multimeter were introduced, modifying the circuit's behaviour and possibly damaging ...
31
votes
4answers
11k views

Reason of multiple GND and VCC on an IC

What is the reason that most of ICs (e.g. MCU) has multiple (A/D)GND and (A)VCC pins? If it is to increase performance of an IC, how does it help to performance? or is it easier for the IC designer ...
12
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4answers
21k views

How should I connect AGND and DGND

I have been reading about grounding in a mixed signal systems. Do I get it correct that it is best to group analog and digital elements and then have a single ground plane, as long as the digital ...
19
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2answers
2k views

Why does connecting a high-current device to my digital circuit cause weird behavior?

I have a arduino microcontroller other digital thing and when I connect a motor pump heater other high current thing I experience weird ADC measurements reboots crashes errors in digital ...
7
votes
4answers
5k views

Should there really be 1 MΩ resistance between an anti-static wrist strap and a pc?

My previous question: what exactly is grounded through motherboard standoffs? The answers suggest that a PC case is grounded in 2 ways: To the ground plane of the motherboard, through the brass ...
15
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3answers
6k views

Why is there a 0R resistor linking GND and AGND in analog voltage reference circuit?

This is related to another question I've just posted (What's the purpose of a ferrite bead inductor on this circuit?), regarding the battery charger described in the AVR450 Application Note - ...
11
votes
5answers
4k views

Anti-static mat connected to earth directly or 1E6 ohm resistor?

Should an anti-static mat be connected to earth directly or with 1E6 ohm resistance in between? 2 layer mat. Upper side: dissipative (10E7 ~ 10E10 ohm/m²). Bottom: conductive. To be a little more ...
5
votes
2answers
36k views

When does and when doesn't current flow to ground?

I was thinking about when current can and can't flow to ground. I came up with that current will only flow to ground when we have at least two grounds in the circuit, since then we have a complete ...
8
votes
1answer
2k views

USB 3.0 Hub shield connection

This is about the seemingly controversial shield to ground connection. The system is basically a body-worn intel-based computer, powered by a battery. Two USB 3.0 (or 3.1 Gen1) cables come out to a ...
7
votes
2answers
3k 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 ...
6
votes
1answer
860 views

Sending ground along with digital connections between boards

I have been wondering for quite a while whether it's good practice when connecting two boards together (powered from the same power supply, although each has its own regulator) to send ground ...
1
vote
2answers
2k views

How to add ground to DC circuit?

I'm just a dabbler in electronic circuits and I'm really still kind of a noob. I am working on a project called the "Atari Punk Console" (Originally known as the "Stepped Tone Generator") but there ...
29
votes
6answers
12k views

Noise reduction strategies in electrophysiology

When recording electrical signals from cells (in a dish or inside a living human or animal body), one major problem is to increase the signal to noise ratio. These signals are usually in the 10uV ...
41
votes
10answers
24k views

Why is an Ethernet cable not grounded?

There is no dedicated GND in the classical Ethernet 8P8C ("RJ45") pinout.[1] Why does the Ethernet spec not include a ground, unlike many other cable types used for interconnecting devices that may ...
20
votes
4answers
19k views

When to use ground plane cutouts?

I've been reading more about proper grounding techniques and using ground planes. From what I've read, ground planes provide a large capacitance with adjacent layers, faster heat dissipation, and ...
14
votes
7answers
106k views

How grounding works to prevent electrical shock

Can someone please explain the how grounding / earthing to prevent a person from getting electrical shock using simple illustration of a faulty electric iron connected to the 240VAC mains? I don't ...
13
votes
6answers
48k views

How to safely ground a switching power supply with floating outputs?

I just received a 120VAC to 5VDC (20A) switching power supply (the kind with a passively ventilated metal casing) for use with a microcontroller project I'm working on (driving long LED strips). I've ...
8
votes
1answer
2k views

Does an ungrounded shielded cable shield at all?

Does a shielded cable provide any shielding if the shield isn't grounded? Would it be practically different than an unshielded cable?
23
votes
4answers
4k views

Why the arc when bonding-on during high voltage repairs?

When working on high voltage power-lines via helicopter the technician will "bond-on" with a steel wand called a hot-stick. During this process an arc is conducted from the line to the wand. Now, ...
1
vote
4answers
332 views

Why earth ground connection does not leak current?

This seems like a question which has been asked multiple times on forums. I researched the problem but I still was unable to figure out the answer which I can at least intuitively understand. So in ...
10
votes
2answers
2k views

Grounding of ADC grounds

Fast, high resolution ADCs, especially ones that have parallel output, usually have a separate supply pin (DRVDD, (drive vdd) or OVDD (output vdd)) presumably because they don't want to couple noise ...
2
votes
1answer
912 views

Portable device shielding & ESD

I'm working on a portable battery-powered device with a shielded I/O connector for sensors, but I'm confused about how to properly ground the shield and ESD array. Here is a block diagram of my ...
1
vote
1answer
423 views

Using aluminium enclosure as heat sink

Can I use the aluminium enclosure of my mains powered product as a heatsink? I'm thinking about mounting TO-220 transistors pressed against the enclosure, to get away with passive cooling by using ...
0
votes
2answers
5k views

Kirchhoff's Current Law at the ground node?

Can one do KCL at the ground node? Does any current go into the ground? I think not, but I am not sure. Bonus Question: If yes, then how does grounding buildings drain the current into the Earth?
8
votes
2answers
3k views

Grounding Metal Object to Eliminate Static Electricity Using Electrical Ground

let us say that I have built a metal cabinet in which I will be painting small objects. I am looking to eliminate any static electricity that could possibly build on the object to be painted or on the ...
6
votes
1answer
417 views

Why do some devices have 200V on the case?

I recently got a desktop LED lamp, and I feel a "strange" slight vibration when touching the metal case. I found that other devices also have high voltage on their case. What is the reason/trade-off ...
3
votes
2answers
539 views

Grounding a laptop through the DC-jack?

I would like to reach zero potential difference between me and my laptop (to avoid ESD) before opening the back cover. I'll connect my wrist strap to a common ground point, thru a resistorized coil ...
1
vote
0answers
216 views

Connect Arduino to existing circuit with seperate power supply

I have an existing closed system that exposes several inputs that I would like to drive with an Arduino. The existing system (Neptune Apex Controller with break out box) is designed to sense the ...
1
vote
2answers
1k views

How to split Analog and Digital GND planes for a TQFN device

This question is in reference to Mixed signal PCB layout for PSoC. If I am using a microcontroller which has separate analog and digital supply inputs and GNDs, what should do with the grounds? ...
0
votes
2answers
3k views

Converting 2 pin plug into a 3 pin grounded plug [closed]

I have a portable power socket that accepts two 2 pin power plugs and 1 pin 3 pin grounded power plug. There is a hole on one side of this portable power socket where the wire goes into. Oddly this ...
43
votes
10answers
20k views

Why is main's neutral tied to earth?

My dad is an Electrician and I myself am an Electronics Design Engineer, and to this day he still hasn't been able to give me a good reason for this. Consider the two following pictures/situations - ...
18
votes
6answers
11k views

How does earthing work when earth is dry?

Earthing is meant to provide reliable contact of an electric appliance to earth so that if there's an insulation fault current goes into earth instead of through a person's body. This requires ...
12
votes
4answers
16k views

Where is the ground/negative for overhead power lines?

I recently learnt that ground can be used to complete circuits using high voltages. I'd like to know if this is how overhead powerlines work, and if so where exactly do the cables/circuit terminate - ...
17
votes
1answer
10k views

With shielded twisted pair cable, do you ground one end, both ends, or neither ends of the shield

I've got a project coming up that's to be doing RS-485 communications over shielded twisted pair cable. The project will involve cable length runs of many 10s of ft and the cables will probably have ...
15
votes
2answers
2k views

Grounding PCB to enclosure

I am designing a small sensor which fits into a custom aluminum enclosure. The sensor uses CAN bus and a long cable to connect it to the host and power. The shield of the cable will ground the ...
12
votes
4answers
3k views

RS485 network ground pin - when to connect?

As many know, one can implement a simple node to node rs485 communication by using only two wires, A and B. Well, the standard specify to connect the ground of the two node together. from Wikipedia: ...
8
votes
4answers
10k views

Why is this laptop adapter grounded?

This adapter is clearly not capable of delivering a null, a power and a ground to the laptop because the connector only has two surfaces. The adapter itself is plastic. So why is it grounded? (Note ...
9
votes
2answers
5k views

Recommended way to connect the exposed pad to ground pins

Is it okay to connect the exposed pad to the ground pins as in the image below, or is there a recommended way to do it?
5
votes
4answers
2k 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 ...
13
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3answers
2k 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 ...
12
votes
4answers
5k views

Why would a power supply unit with insulating case and galvanic separation need a grounded power cord?

Recently I witnessed an external IBM laptor power supply that looked like a usual switched-mode power brick (rather small and lightweight for it more than 50 watts power) in plastic case but had a ...
11
votes
1answer
3k views

PCB 'Emi proof' design

Currently I'm designing a GPS basestation which will have a radiomodem (broadcasting at 407-480MHz), a ARM7 microcontroller running at 60MHz and a FTDI USB chip. The FTDI USB chip even runs at 480MHz ...
7
votes
2answers
2k views

PCB design review: Decoupling, bypassing and grounding

I'm trying to make my own wireless sensor using ATmega microcontroller. I've some basic understanding of electronics but I'm a total amateur when it comes to designing circuits and PCBs. This is just ...
6
votes
3answers
4k views

For a 4 layers PCB (with ground plane), covering with ground polygon on Layer 1&4 necessary?

For a single or double layered PCB board, usually I will cover all the empty spaces in the layout with Ground. This is the 1st time I am designing a 4 layer PCB layout. Layer 1: top signal (high ...
4
votes
2answers
488 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 ...
4
votes
1answer
5k views

Why is neutral wire connected to ground at the transformer?

I understand the use of ground wire at the home appliances but why is the neutral wire connected to ground at the transformer? Why doesn't the neutral wire go back to the power generation plants. I ...