Ground or earth is the reference point in an electrical circuit from which other voltages are measured, or is a common return path for electric current, or a direct physical connection to the Earth.

learn more… | top users | synonyms (1)

6
votes
2answers
1k views

Multiple grounds from diode bridge? Safe or really stupid/dangerous?

I am making a hybrid tube preamplifier (one vacuum tube and one op-amp). Both use very different voltages - the tube is getting somewhere about ~150V DC and the op-amp gets ~6V DC. The differences ...
1
vote
3answers
41 views

4017 Counter LED Shuffle By Touch

Hi all, I found the following circuit on the internet and made it on the back of a business card as a fun project. The idea is that you ask a question, touch the naked wire, the lights shuffle and ...
0
votes
3answers
78 views

Aluminum sheet as an underlay for electonic equipment

I am planning to build a NAS into a (sufficiently ventilated) closet. For flame protection and heat spreading, I mean to put a 2x700x550mm aluminum sheet under the equipment. Is this a good idea? ...
0
votes
1answer
70 views

Voltage difference between two individual voltage sources

I have two voltage sources. The first one is 230VAC to 5VDC cell phone battery charger while the another is output from Raspberry Pi's Ground and 3V3 pins. I feed the 5VDC output for an Arduino. What ...
0
votes
1answer
28 views

audio mixer - is ground isolation needed for each channel?

In every audio mixer schematic that I have found, the signal circuit is described extensively. Here are a few examples: However, these diagrams do not show any considerations for the ground ...
0
votes
3answers
66 views

USB cables combining shield and power ground conductor

I see a lot of USB "charging" cables on the market with cutaways showing two small data conductors, one large power conductor, and shield. The implication is that power is conducted in the shield. ...
0
votes
0answers
15 views

Simulated analog narrow band output ground loop

I am using a Wide Band Lambda controller with a simulated analog narrow band output, the controller system must be grounded to the chassis and is also shared with analog common which connects to the ...
0
votes
2answers
50 views

Input resistor to BJT base > ground resistor, why?

Thank you for your time. I'm new to electronics and so this question might, to you, call for an evident answer. Nevertheless, I can't seem to find that answer. I've stumbled upon a schematic for a ...
18
votes
1answer
274 views

Does anyone know the history of the earth ground symbol

I Googled for hours, asked every EE professor in my college, then checked every electrical engineering book in my university's library (hours), and have found nothing about the history of the ground ...
1
vote
2answers
43 views

Connection to ground for a Cat5e Shielded outdoor rated cable

My ISP installed the cable modem in my entertainment room. I am trying to have internet also in my STUDIO with an access point to broadcast a second WIFI from there to other parts of the house. (My ...
0
votes
4answers
114 views

Where do these grounding wires go? [duplicate]

In the following schematic the two Vss pins where are supposed to be the grounding pins don't connect to anything. Does this mean that the circuit is self-grounding (if that's even a thing)? I'm ...
0
votes
4answers
167 views

I always thought that bodies of water were ground

I always thought that bodies of water were ground, meaning that any electric voltage that meets a lake for example would be immediately become grounded and the voltage would be that of the earth, in ...
1
vote
1answer
58 views

Varistors set to ground or case by isolated ground/case

I have a isolated ground from the case in my device. The Supply Voltage is +24VDC with Ground and separated CASE, so no safety issues. On any signals coming from the case (Plugs) I put varistors, but ...
2
votes
0answers
58 views

How to calculate the earth fault current in a transmission system with no ground wire?

Background information, and my thought on the matter are provided in the end of the question. I need to calculate the fault current in case a fault occur for instance 10 km away from a transformer ...
1
vote
2answers
70 views

Hot & neutral have similar voltage to ground: Finding the problem Part 2

I accepted an answer to a similar question recently, but I now have additional information and have realized that I need a more specific answer. I am nearly certain that my landlord will be unhappy ...
0
votes
3answers
39 views

How to make multiple GND pours in Altium?

I have a PCB design that requires two ground pours on the bottom layer, one is AGND and the other is DGND. Most of the board is AGND ('L' shape) and the remaining should be DGND. I have tried to pour ...
0
votes
3answers
42 views

Is dual power supply's ground coupled?

I am using a dual power supply model CPX200 from TTI in my school lab, and I am trying use it to supply 1.8V and 3.3V to a PCB, so I figured it was a good idea to check whether the ground of the dual ...
0
votes
0answers
38 views

External whip 868MHz Antenna via coaxial cable. Ground Issues

I have a RF module that works at 868MHz.It works as transmitter and as receiver. (lambda:0.345m lambda/4=8.64cm). The RF module ground plane (GND_PCB) is 10x10cm, so bigger than lambda/4. By default, ...
0
votes
0answers
41 views

Oscilloscope builds charge on ground even when it is connected to mains ground

I have a following situation - my scope (UT4102C if that matters) builds some charge (quite painful to touch) on its ground (BNC connectors outer hull) even when it is connected via proper IEC cable ...
0
votes
3answers
84 views

Are capacitors floating power supplies?

I'm struggling with the concept of floating voltages. For a grounded supply I can connect one side to an effectively infinite ground and get full power. It may vary depending on its construction, ...
1
vote
1answer
57 views

Practical differences between putting circuit complexity on the ground side vs the hot side

I'm wiring some computer fans behind the fridge in my camper-van to help increase ventilation. As part of this circuit, I have a temperature controlling microcontroller plus relay and a series of SPDT ...
0
votes
1answer
75 views

Ripple flowing through probes connected to the same point!

While trying to filter the ripple of my switching PSU, I've come to a phenomenon that is probably well known to professionals, but seems absurd to me. Admittedly, my scope is not of the highest ...
0
votes
1answer
64 views

I/O card couples analogue ground to 0V - how can I work around this?

I'm building a system that has to measure analogue voltages accurately. This system is being tested using PC-based test equipment that has an expansion card in it generating both digital and analogue ...
0
votes
2answers
63 views

How to detect pin state change in pulled up pins

I am working on Toradex module and developing a simple application where I am detecting the input and displaying it on UART. Now the application requirement is that we give 12v as input but the ...
3
votes
4answers
432 views

How does grounding the circuit provides safety?

I don't understand the concept of grounding a circuit for safety reasons, in this circuit that i simulated, imagine my hand touching the circuit as the closed switch. I am creating a closed loop ...
0
votes
1answer
67 views

Altium - How do I place my GND vias?

I have a 4 layer design, Top, layer2, layer3, bottom. Now I want to place GND vias on a ground polygon. Layers Top and Bottom both are a complete ground plane (Polygon) I was wondering; What is the ...
3
votes
2answers
345 views

what is a ground? [duplicate]

I have a basic question about electronic ground. For example, if electrons travel from the DC battery's negative terminal through the conductive wire to the positive terminal of a DC battery with a ...
0
votes
1answer
74 views

Cons or pros related to connecting analogue and digital grounds together using a ferrite or inductor

I'm designing a signal acquisition system with an ADC. I have these questions: 1- Any cons or pros related to connecting the analogue and digital planes using ferrites or inductors. Or should I just ...
3
votes
1answer
79 views

Is it good practice to couple the grounds of isolated supplies with capacitors

I once saw the following on an isolated dc/dc converter data sheet and have been doing it ever since with my dc/dc converters, but I wanted to ask to make sure it actually makes sense. Whenever I ...
1
vote
4answers
124 views

What do these dashed/dotted lines mean in this power cord schematic, and how should I ground this device?

--Edited at Sparky256's suggestion for better clarity-- Background Information I'm making a power cable for a piece of obscure, surplus military equipment (an AN/UGC-74B teletype, to be precise). I ...
3
votes
4answers
227 views

How does ground mains work?

When I studied how AC mains power works, I learned that one of the wires is connected to the ground or a body of water so that it can get back to the power station. The concept baffles me. Every ...
0
votes
1answer
49 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 ...
2
votes
1answer
144 views

Pulling the circuit's voltage to the ground with grounded probe

When measuring a point on an isolated circuit board with my grounded oscilloscope, I fear my oscilloscope ground will pull the measured point to ground level but this has never happened, I am always ...
1
vote
1answer
63 views

Return Path of Bypass Capacitor in a PCB with 2 Grounds

I have a PCB with two power rails, 5V and 12V, and two ground pours, GND-5V and GND-12V, respectively. The two ground pours are tied at one point (close to the connector). I'm powering a DAC off the ...
3
votes
2answers
71 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
74 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 ...
0
votes
1answer
33 views

Protecting GND from RS-232 voltages

I have a project that uses this two wire RS-232 trick: http://circuitcellar.com/cc-blog/one-wire-rs-232-half-duplex-ee-tip-135/ It combines RX/TX into one wire while the other is ground. However, I'...
5
votes
4answers
1k views

Antistatic mat , how it works?

I have a large anti-static mat lying on the table of my workdesk, which looks like this. And it's connected to ground through the wall outlet from one point, meaning it's an open-loop: Let's say I ...
0
votes
2answers
143 views

Power cord without ground cable

Ground cable was ripped from the power cord of most expensive oscilloscope in the lab . Neutral and line cables are stil there . Do you think this is done on purpose ? if so , why ?
0
votes
2answers
78 views

Grounding dc project to clean RF noise

I'm doing a home automation arduino / RFID project and using a 12v DC switch mode power supply to power it. This supply will be plugged in to a wall outlet. The project however will have some ...
1
vote
0answers
17 views

ACPL-C79B problem

This is my first post on this forum. I have a problem with an isolation amplifier and i hope there's someone here who can help me out. Let me explain my situation. I use an ACPL-C79B from Avago to ...
0
votes
0answers
42 views

Floating Ground Adapter for Car audio line level signal?

I have a an Audi that uses the Bose external amplifier. Bose/Audi designed the system to use a single common between the head unit line out and the Bose amplifier line input, so it is four wires (FR+, ...
6
votes
2answers
95 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 ...
1
vote
2answers
111 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 ...
2
votes
4answers
163 views

Difference Between - (Minus Sign) and Chassis Ground in Schematics

I was working on building some projects from the book Electronic Projects for Musicians and I noticed that in most of the schematics there are two symbols for what seems to be ground. One is a - (...
0
votes
1answer
59 views

Should vias really have bridges?

I have been always using bridges with vias. I gues that doesnt hurt but recently I though is it really necessary? I know that they're purpose is for the soldering process to be easier, otherwise ...
1
vote
0answers
57 views

Ground versus negative terminal in a data sheet

In the following datasheet. At some point it says : "If the option for synchronization is not used, the synchronization input has to be connected to ground (0 V) or the sensor must be operated via a ...
0
votes
1answer
47 views

Controlling multiple inputs without a common ground using semiconductors

I have a processor with GPIO outputs. It uses 3.3v logic outputs which share a common ground. (In particular, it has internal pull-up resistors, but I could turn on open collector mode) A device I ...
1
vote
2answers
85 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 ...
0
votes
1answer
91 views

Oscilloscope ground oscillating [closed]

I turn on the oscilloscope, work a little, then I remove the cables and after a while when I want to use it again, I notice the ground has moved 0.4 or 0.6 V upper or lower than it was half an hour ...