Problems related to the connection of circuits to ground or earth references. Can affect safety, accuracy, reliability and interfacing.
4
votes
0answers
85 views
Placement/routing of decoupling cap straddling oscillator guard ring on dsPIC
Changes in my design are forcing me to replace my 44-pin dsPIC33FFJ16MC304 with a 64-pin (same package size, finer pin pitch) dsPIC33FJ64MC506. In the datasheets for both chips, Microchip recommends a ...
1
vote
1answer
102 views
Oscilloscope ground clips sparks while connecting to power supply
Oscilloscope ground clips sparks while connecting to power supply ground. I do understand The clip is connected to earth ground. But why does it not spark when I am powering a circuit of the supply?
6
votes
4answers
241 views
How to handle unused wire in cable
What is the best way to handle an unused wire inside of a cable.
Let's assume I've got a cable with 4 wires, only 3 of them are used.
I could connect the 4th wire at one end to ground, at both ends ...
0
votes
1answer
137 views
How does this heavily oxidized copper-to-steel joint work in earthing?
Wikipedia article on grounding features this photo:
Here's a close-up of the joint:
Clearly the steel rod is heavily oxidized and the copper wire is oxidized. The clamp is coated with something ...
7
votes
2answers
197 views
Grounding and why charge leakage occurs
A basic nugget of info is missing in my end-to-end picture of how grounding works and why it's important. When a voltage is applied in a circuit the electric current starts flowing (or the field ...
0
votes
0answers
136 views
Oscillating op-amp due to grounding issues?
I am working with an op-amp as a voltage level shifter for a 'black box' piece of equipment. The circuit works by it's self, amplifying a square wave correctly but when it is connected to the 'black ...
5
votes
2answers
145 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 ...
3
votes
1answer
198 views
Ethernet phy connection: grounding between chassis, connector and IO
The phy chip I'm using has a evaluation board which grounds the chassis, connector and signal gnd points in the following way:
However, I don't really understand why the MCTx connections are ...
5
votes
1answer
217 views
How is the following ground symbol different from conventional ground?
I've seen the following ground symbol in quite a few schematics:
How is this different from the typical GND symbol?
6
votes
3answers
164 views
What do I do with the extra “ground chassis” tab on a DC power jack?
Product Link
Datasheet
I have about fifteen 9v wall warts within specs for the circuit; I'm going to use the one that fits the jack. There are three solder tabs on the jack. One for the positive ...
7
votes
2answers
183 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?
3
votes
2answers
809 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 ...
2
votes
2answers
142 views
Can current be drawn from ground in a SWER transmission setup?
I am almost certain that this is a ridiculous question, but cannot figure out why this scenario would not work.
From what I understand, current from the electrical station is distributed to houses ...
1
vote
1answer
72 views
Help with grounding a generator on a running vehicle
Ok, this may be basic, but I can't seem to find a solid answer. If I have an AC generator in use on-board a running vehicle (that is being driven), is a GFCI enough or must some sort of grounding be ...
4
votes
2answers
142 views
grounding connection?
What's the easiest way to connect a ring terminal to the ground terminal of an AC outlet? Are there plugs you can buy that make this easy?
I don't need (or want) the line and neutral wires ...
14
votes
3answers
497 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, ...
2
votes
2answers
1k views
Grounding a DIY power supply
I am trying to develop a bench power supply. Now, before going on, I do realize that there are really cheap commercial ones available. I have two. I want to develop one my self.
The way I have ...
2
votes
1answer
186 views
Why do TQFP and TFQN have different advice regarding analog ground?
This question is in reference to How to split Analog and Digital GND planes for a TQFN device.
For the PSoC3, the advice on how to separate the analog and digital ground is different depending on the ...
1
vote
2answers
239 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?
...
2
votes
0answers
70 views
Ground problems in kitchen [closed]
i have had some trouble in my kitchen recently about some tingling stingy feeling while touching the kitchen sink. and stove metal.
my toughts is that here is some ground problems but I could not ...
3
votes
2answers
266 views
Captive Nut For PCB Grounding
I need to affix a ground strap to my PCB. A strap similar to .
Ideally I want to simply screw this to the board. Are there captive nuts available for this purpose? I can't find anything via a ...
7
votes
2answers
1k 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 ...
3
votes
2answers
852 views
How to check if something is mains earth grounded?
Suppose I would like to verify that the ground terminal on an indoor power outlet is actually connected to the ground (from what I've read, some of them aren't!). How would I go about checking that?
...
2
votes
1answer
124 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 ...
6
votes
2answers
156 views
Grounding Shielded Panel-Mount Connectors
I'm building an amplifier in a conductive metal chassis. The general grounding plan is to have an audio ground, a power ground, and a digital ground that converge at a single point on the chassis. ...
9
votes
1answer
2k 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 ...
0
votes
1answer
108 views
High voltage metallic shield grounding
What size of conductor I have to use to ground the shield of a high voltage cable? I would guess that the size of the grounding conductor is related to the size of the cable, but I'm not sure.
5
votes
2answers
677 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 ...
1
vote
4answers
1k views
Should NC-Pins of IC connected to ground through a resistor to prevent noise?
I wonder if unused pins of an IC, lets say an NE555 f.e., should be connected to ground via a resistor to prevent noise or not. I have an AVR with analog inputs and just realized there's huge noise, ...
3
votes
2answers
334 views
Why the measured voltage increases when I change ground reference?
The following image shows my connections:
The grounds of all devices are connected to a common PCB. When I measure the 1.2V referenced to the ground on my PCB, it reads 1.201V which is great. But ...
17
votes
3answers
1k 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 ...
2
votes
3answers
200 views
building my own lc meter - multi point gnd
I'm building my own lc meter using the attached schematic. What I don't understand is why there is more than one path to gnd? Does it not eventually get connected to the same point?
14
votes
6answers
2k 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 ...
3
votes
4answers
4k views
Why should a circuit be grounded?
Why should a transistor circuit be grounded? The way I understand it is that ground is an infinite supply of electrons and so it is equivalent to the negative terminal of a battery. But in this page , ...
1
vote
1answer
357 views
How should I organize this star grounding network?
I am trying to lay out a PCB for a SEPIC switching regulator. However, I cannot be sure how to layout the ground tracks. My area and budget are limited and my components are big. A picture says more ...
5
votes
3answers
314 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 ...
2
votes
1answer
587 views
How am I able to jump my car when I ground one of the jumpers?
Electrically, when I think of jumping my car, I visually see basically putting a stronger voltage source in parallel with a weaker voltage source (see http://imgur.com/qz8jX). However, on every car ...
1
vote
2answers
264 views
Newbie: ATmega32u2 USB-powered - how to ground?
In ATmega32u2's reference manual, there's a diagram for USB-powered application like shown below.
Should I, or should I not, connect the GROUND to VSS/UVSS line? And why? If not, then what to do, ...
48
votes
6answers
7k 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 ...
3
votes
1answer
326 views
how much is it safe to common-ground power supplies?
Some circuits requires more than 1 power source for voltage comparison or whatever reason and the circuit requires that the power sources shared the common ground. Most of the time it works perfectly ...
7
votes
2answers
465 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 ...
8
votes
4answers
1k 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 ...
6
votes
1answer
770 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 ...
