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.

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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 ...
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55 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 ...
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65 views

Can some help me understand this ground switching circuit?

I am trying to understand a switch circuit related to a project that I am working on. Pin 1 - 12v signal for switch backlights Pin 2 - 12v signal for switch on/off indicators Pin 3/4 - Unused Pin ...
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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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29 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, ...
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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 ...
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120 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 ?
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51 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 ...
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14 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 ...
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25 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+, ...
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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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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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122 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 - ...
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54 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 ...
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56 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 ...
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42 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 ...
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68 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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Three Phase (kVA) Utility Contribution, and the Line to Ground (kVA) Utility Contribution?

I have a single line diagram starting with a 25kV Utility line servicing a pole mounted 25kV-600V, 75kVA transformer which feeds a 3 pole 150A breaker that is connected to a power meter. How do we ...
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89 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 ...
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138 views

Wire the green ac earth wire in wooden chassis?

My own power supply is just about finished. Since i live in Europe the voltage here is 230v, from that it goes into my step down transformer that steps down the voltage to around 20 V AC and then into ...
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89 views

Using the neutral instead of the earth to supply electrons

I'm working on a VAN DE GRAAFF generator and I need to connect the bottom comb to the earth ground. But in my country we do not have a ground line . Can i use the neutral line instead and connect the ...
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36 views

Why do IC's have so many grounds? [duplicate]

Is there a technical reason why the multiple ground pins aren't tied together internally? I can't see any real reason as they all get connected in the same way.
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ADC EVAL_AD7984_PMDZ voltage source and signal source sharing common ground

EDIT: (problem definition shortened into 2 sentences) For anyone using EVAL_AD7984_PMDZ and having troubles to apply -2.5, 0, 7.5 [V] and signal to differential probes, because the voltage source and ...
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44 views

Connecting Ground Paths of Low-Current and High-Current Circuits

A small (3.3V/10mA) uC circuit requires a ground. I designed the circuit’s PCB to use a nearby ground wire that is attached to the car’s frame in at least two places and used by the 2A windshield ...
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34 views

Common Ground to Earth?

I am looking into building this stereo amplifier based on this circuit: 2 x 22 Amplifier However, as I am pretty new to circuit building, I have a question about the ground lines: Do i tie all of the ...
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71 views

Is it okay to use a screw and a nut to connect minus wires from parallel circuits?

I want to connect several 12 Volt sockets in parallel. On the positive side the wires are connected to a fuse box which is connected to the positive pole of a 12 Volt lead battery. How do I connect ...
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48 views

How to connect 2 different power supplies together

I have a power supply that provide the following outputs (+&-15V) & (+&-10V) sadly this power supply is obsolete so I have to get those voltages from two separate power supplies one that ...
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53 views

Is it possible for lightning strike to travel up ground / earth pin on a mains outlet?

I live in a country that follows the UK mains specification, where there are 3 pins on a wall outlet with the topmost pin being earth/ground. Now, is it possible that during a lightning strike, extra ...
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41 views

ATX PSU 3.3V output dead short with ground

On an ATX PSU, 3.3V output was dead short with ground (checked with DMM),once i powered ON the PSU 3.3V output was providing the rated output (3.3V) how this is possible?
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USB Power - The basics

I am new to designing something to be powered by USB. Ideally It can either be plugged in to an adapter to a UK wall plug, or a powered USB port on another device. I have the circuit design in place ...
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3answers
135 views

Understand Ground

I am confused regarding the attached image due to lack of understanding of ground. It's a basic question i.e. "How do I setup ground in my bread-board." Tried finding it but the confusion prevails ...
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27 views

Ground wire in custom capacitance-dimmable metal lighting fixture

I'm wanting to design my own lighting fixtures, both for cost effectiveness as well as the design appeal (inspired by a particular designer's lighting fixtures) that uses a wooden base with metal ...
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23 views

Can I connect the capacitor to the GND pin of ams1117 [duplicate]

I am using an ams1117 to drop the voltage to 3.3 V. I saw this diagram: http://www.ams-semitech.com/attachments/File/AMS1117_20120314.pdf I see that I need to use some capacitors on the input and ...
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52 views

TIP-Barrel test of oscilloscope

I am trying to measure the noise at the output of my buck regulator. I am getting some ripples. I feel that the ground loop caused by my oscilloscope GND ref might have a small impact here. I was ...
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3answers
135 views

Why can't we read voltage between just one pin of a loaded capacitor and any ground? [duplicate]

I know that we can only read voltage across a capacitor if it's two pins are connected to the voltmeter or can't talk about any potential difference between totally different systems if they do not ...
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85 views

Arduino: Measuring Current, Voltage + using the 5V and GND pins

I am new to the Arduino world and I don't wanna destory my brand-new Arduino, so I am asking here first. Basically what I am doing for a school project is creating a circuit that will measure current ...
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3answers
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Bipolar output from DAC with unipolar supplies

I want to use a unipolar 12-bit DAC (MCP4725) as a function generator with bipolar output (from -2.5 to +2.5V). Problem is, I only have two supplies of +5V and +12V referenced to the same ground, so ...
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39 views

Connecting monitor to battery powered circuit

I am in the process of putting a battery powered circuit together to test screens on vga monitors. Would I need to do anything with the ground pin or can I leave it unconnected?
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131 views

Is it safe to use two power supplies to two different circuits independently sharing the same ground?

I have a Odroid-U3 minicomputer where its USB VBus and Ground pin are shorted, making the USB ports unusable. But I was able to make a workaround. What I did was used an external power usb hub, ...
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1answer
69 views

Is it safe to have common grounds in this circuit? [closed]

For the sake of simplicity, I draw the illustration above. System A is a device which is fed by a power supply 110V AC, and has sinusoid output with varying amplitude from 1V to 7V peak to peak. ...
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156 views

How to provide an isolated ground for Arduino?

I am designing an EEG circuit at home using an Arduino. Now, the circuit calls for the use of a battery and an optocoupler-isolated ground for safety reasons. I am planning to use Fairchild ...
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1answer
87 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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1answer
72 views

Why is -48V used? [duplicate]

Why does telecommunications equipment in the field (e.g. a BTS site) run on -48V? What is the advantage of running it at a voltage lower than ground rather than using a positive voltage?
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1answer
54 views

what are the advantages of connecting two GND polygons only in one place on PCB?

Could you help me understand, why is connecting two polygons of the same net (for example GND) in just one place proposed? What is difference if we connect pGND (power GND) and sGND (signal GND) with ...
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302 views

Why does a UPS need an isolation transformer?

Why would we need isolation transformers before and/or after for a UPS system? What are we trying to protect, and from what? I have read that it has to do with grounding and neutral but I didn't ...
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36 views

connecting a generator with an RCCB to a service panel

Consider the following schematic : simulate this circuit – Schematic created using CircuitLab in this setup we have two power sources Main power lines and a diesel generator ( with ...
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205 views

Proper way of connecting logic GND / power GND on MOSFET driver

I am tring to build half bridge using IR21844 mosfet driver, i have read datasheet and design tips and some of the topics in this forum. The one thing i still cannot get is the separate GND pins ...
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768 views

Using Oscilloscope So That Nothing Blows Up

I want to see the input current waveform of an LED T8 18W. An EM ballast is purposely placed in series with the lamp. I don't have a power analyzer. What's available is a GDS-2102 oscilloscope. So I ...
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131 views

Does 3.3v ground and 5v ground connected will affects circuit?

I have a wifi transciever(ESP8266) which should be connected to 3.3v and microcontroller connected to 5v(PIC16). For establishing the communication between the microcontroller and wifi they should ...
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132 views

Why is AC earth connected to DC ground in laptop adapters?

If I were to plug this type of adapter into an ungrounded socket then voltage will leak to the DC ground through the AC filter capacitors. So why is the DC side not left floating? What are the ...