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Questions tagged [ground]

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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ground connection for isolated rs485

Is it necessary to connect isolated grounds for 2 different isolated RS485 nodes? For instance the following isolated RS485 breakout board doesn't have any GND connection in the board. https://www....
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4answers
377 views

What Reference-Potential does an Operational Amplifier use as “Ground”-Potential?

Wikipedia states on operational amplifiers, that, simply speaking, they provide an output voltage at their output which is the difference of the two input voltages, multiplied by some (very very large)...
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How series resistors influence clearance-creepage requirements?

simulate this circuit – Schematic created using CircuitLab I'm designing a circuit which should leak some amount of current from AC line to PE. The question is regarding clearance-creepage ...
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Hook up an automatic transfer switch with two phases only

We have a house in Haiti connected to the shore line. The shore line isn't always working so we bought a generator. I wanted to ground one of the two phases to create one neutral, one phase and a ...
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54 views

If we have four grounded nodes in a circuit, can we connect two of them together and forget that those two were grounds?

Refer to the image attached. I personally think the answer is no because it is not necessary for the currents through both the grounded capacitors to be the same in the upper circuit, but that is not ...
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78 views

Grounding a Laptop

I have the following problem: I am currently debugging an electronic sensor board which is connected to the USB port of a laptop. The USB port is used both for communication via UART and to supply ...
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113 views

Voltage gradient across an antenna (and how it drives an AM radio)

Edit: I was interested how is voltage gap maintained across an antenna. It seemed to me that an antenna might be like a wire where if there's a voltage at the top, the same voltage would be at the ...
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60 views

Moving Ground in between resistors in series

What happens when you move Ground to the given point? How does it affect the Voltage and the Resistors after moving it in the circuit? Missing values: .Current (I)= 30mA (V.R1)= 15V (V.R2)= 3.6V ...
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VITA 46.0 VPX grounds isolation requirement

VITA 46.0 VPX standard demands: Rule 3-15: Plug-in modules shall provide a minimum dielectric withstanding voltage of 500VDC +/-10V and a minimum resistance of 1 megaohm between safety ground and ...
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1answer
57 views

Substation grounding

I am trying to understand a grounding system for substations, fault current is something I am not getting. For example, for a small substation with some transformers, if there is a fault in the system ...
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27 views

Altium: Via stitching not connecting to plane?

I'm experiencing an issue in altium where my Via stitching vias on the GND net will not connect to my ground plane. Individually placed vias will connect fine through from the top layer polygon GND ...
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2answers
58 views

What is the purpose of grounding rectifiers?

In the centre tapped rectifier: It seems as if the highlighted ground line would provide a short circuit for any current developed between the top/bottom wires and the centre tap, eliminating any ...
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21 views

Relay if powered with ac supply then turns adjacent circuit on automatically

I took the idea from the below link to build my own relay board. http://www.electronics-lab.com/project/toggle-on-off-switch/ I connected 3 of this in parallel with voltage. All seems well until I ...
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234 views

Disconnecting ATX PSU's ground from mains earth to protect my oscilloscope

Like many I took an ATX PSU, hooked green to black, and have a nice PSU. I am experimenting with a HP oscilloscope from 1997 and as you know, those are grounded to main's earth, just like my ATX PSU. ...
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2answers
42 views

Current Sensing problems in PWM-switching circuit

I have the following circuit: simulate this circuit – Schematic created using CircuitLab A simple voltage source is connected to a resistor. The current flow is controlled via an NPN switch. I ...
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2k views

Is it ever bad to run an IC VCC trace next to a ground plane with 1mm clearance?

Since my last board flopped, I looked at it again and noticed a ground loop (because the DB9 casing completed the loop). Now I adjusted my board so that there is no loop of any kind. Instead, I'm ...
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4-20mA with 12V sensors using ADS1115 ADCs

I am currently designing a 4-20mA current loop with external sensors which work at 12V DC. I saw a differential application on the datasheet of the ADS1115 ADC, but the simple shunt resistor I believe ...
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1answer
57 views

What options are available for measuring grounded thermocouples?

I'm using 4 MAX31855 ICs to measure 4 K-type thermocouples and realized that 2 of my thermocouples have grounded junctions; I simultaneously also realized the MAX31855 is stated to not support ...
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3answers
64 views

Shield grounding for analog sensor

I have an analog sensor, a resistance temperature thermometer, which is essentially just a resistor (~50 Ω) which I apply a constant current to (10 mA) and measure the voltage of in order to ...
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1answer
31 views

Eagle: How can I connect a Polygon IFA to GND

So I've just completed my Inverted F Antenna (IFA) as a polygon in the brd view on Eagle, I can connect the input section quite easily with an wire. Whilst the GND section of the IFA I'm having a bit ...
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1answer
45 views

Circuit Analysis in Non-Closed Systems

So I'm fairly confident in my ability to do circuit analysis on closed circuits, that is, circuits where all loops, sources, and elements are given. However I still find myself getting stuck on ...
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1answer
85 views

How to break this ground loop in my car?

Here's the schematic for my car: simulate this circuit – Schematic created using CircuitLab The head unit is referenced to car's chassis. My amplifier and DSP are in the trunk. The DSP has an ...
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1answer
63 views

Connecting all grounds directly to the supply's ground?

I currently have this layout on my PCB: As it appears, the grounds from the different components are connected to each other and then connected into the supply's ground. In the context of amplifiers,...
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Safety of the input

I have been shocked by a faulty piece of equipement (valve preamp) about 3 years ago. This kind of equipement use lethal voltage to run the valves (450VDC is common). I want to protect myself ...
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Is this correct way to connect chassis ground to digital ground?

I'm currently working on a PCB and I'm not sure how to connect a digital ground and ground chassis. The picture shows the PCB layout where you can see the 3-pole power connector (L, PE and N). Pin 2 ...
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1answer
53 views

Replace a relay with an analog switch

I'm trying to replace a relay with a SPDT cmos analog switch MAX4678 for switching a sine wave, The switch is powered with dual power supply +5/-5 and +5 to its V_logic pin. This is what i got in ...
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Why did this arduino burn out? SilentStepStick (TMC2130) stepper at 24V

I'm new to electronics. Attempting to bench-test a SilentStepStick stepper driver board, (based on a TMC2130) Using: Arduino Uno, a SilentStepStick driver board, a 0.6A stepper motor, and waterott ...
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1answer
50 views

PCB antenna and SMA connector

I have a question regarding an integrated PCB Antenna that I would like to try out, however, if it fails I want to be able to use another SMA antenna. The PCB Antenna is an inverted F-antenna meaning ...
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2answers
701 views

GND plane and vias on a two layer PCB

I'm trying to build my first two-layer PCB layout using this example schema: I'm using SMD elements, which I would place on the top layer. Also I would create a ratsnet area as GND on the top layer. ...
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1answer
107 views

USB shield for analog and digital ground?

I'm new to Mixed-signal design and I'm having trouble deciding how to connect my digital and analog ground. I'm doing a 4 layer design, so I have a split ground plane. As I understand, since I'm ...
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2answers
87 views

Putting GND on POWER layer

I have a four layer PCB, with a traditional: signal layer, power layer, ground layer and final signal layer. Due to the set up with the power rails, there are some large spaces on the power plane ...
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1answer
30 views

EAGLE - how to make ground planes to connect to the smaller PADS

I cant fid how to configure the GND polygon to connect to smaller IC pads: EDIT Following the @Dave Tweed answer the result is exactly as I need:
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81 views

reason to have entire Cu layer as GND connected through via (KiCad)

This is the first time I am designing a PCB and I was looking at example PCBs drawn in KiCad (the image below is my first PCB, to remove any sources of confusion). I noticed that oftentimes, when ...
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55 views

how can accsess gnd in full wave rectifier? [closed]

in full wave rectifier without transformer how can access to gnd for regulator or gnd of microcontroller? (assume we dont have trouble with amplitude of voltage) I think in full wave rectifier in ...
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37 views

Pour ground plane fails in Circuit Studio

could you please advise on the following topic: First time I make a ground plane in circuit studio. I really follow the tutorial. I select the pour polygon as you see. Ok here I named the plane GND,...
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2answers
52 views

Three Different Voltage Lines, Same Common Ground?

I am trying to send PWM, clock, latch and blank signals from Arduino through a series (16) of TLC5940 Breakout boards and on to a grid of 512 individual controlled LEDs six feet away (RJ45). I am ...
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1answer
34 views

Altium Gerber File Copper Breaks

I'm getting some really weird effects on my Gerber File outputs from Altium Altium 18.1.9, using OutJob Files, here are my settings My layers look completely normal with a copper pour for the ...
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87 views

RS232 signal ground

I have serial sensor wich i need to connect to a datalogger via RS232 interface. Sensor powered by datalogger. But datalogger have no signal ground pin, only power ground. So i connected sensors ...
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1answer
45 views

mains earth and op-amp ground

I was trying to power a transimpedance amplifier built with an op-amp on a protoboard. I only had a power supply that looked like the first image below (no COM, which I would have connected to GND ...
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2answers
356 views

Power supplies with or without 'COM' and without ground port at all

This is probably something really simple, but I wasn't able to find the answer yet. I've been using a power supply with both COM and earth ground, like the first image below. To power an op-amp, I ...
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3answers
121 views

How to find Voltage based on reference nodes?

I came across this problem and I'm trying to really understand it. VB is the voltage drop across a particular element, it is the change in voltage from node a to node b. Find the value of VB in ...
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1answer
109 views

Wire to VDD or GND?

In the circuit below, there are four LTC485 ICs, one input (left), three for output (right). Pins 2, 3 and 8 are going to +5V, as well as GND. So where should I connect them to? Should I wire them all ...
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28 views

low impedance as GND and current measurement, applied voltage sharing the same lead

(Image 1 is for the general idea, image2 is for questions 1 and 2, image 3 is for the 3rd question) In the setup shown below, the tuning fork is driven by an AC voltage source being connected to one ...
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1answer
85 views

GND connections and ground plane routing?

When I let Altium do autorouting and then I define a ground plane using a polygon connected to my ground pin, I often get layouts where a GND line is flanked on both sides by the GND polygon, and then ...
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0answers
53 views

Bi directional logic level converter not dropping voltage to ground

I made a Bi directional logic level converter according to the following document https://cdn-shop.adafruit.com/datasheets/an97055.pdf but am experiencing a weird behaviour. One side is connected to ...
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1answer
33 views

Long vs Short Earth Connection for Single Phase Motor vs 3 Phase Motor Frame

What is the correct way of grounding single phase motor frame if I have to choose between two options: (1) Short to earth connection: from the frame to nearest grounding rod. See below the schematic....
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535 views

Single ground plane vs split planes?

I have seen conflicting sources about ground plane design. I have been told at my work many times, just slap a single massive ground plane in and that works well enough, we don't deal with anything ...
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1answer
63 views

How to build (from scratch) a GFCI Circuit? [closed]

I am looking to understand what is the circuit inside a Ground Fault Current Indicator (GFCi). What does the circuit look like? Simple google search is not yielding good results about the guts of it.
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348 views

Why am I getting shocked from “hot” line and touching “ground” (Earth)

So I live in an EU country and don't have Earth grounding for my house. Still I am getting shocked when touching "hot" line (220VAC) and standing on "ground" (Earth). How is this possible? From my ...
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48 views

strong noise in microphone unless usb receptacle is grounded

I installed a Banana Pro (like Raspberry Pi), plugged an usb audio stick in, and a microphone in it. I run this thing with a properly dimensioned usb power supply (tried different ones). This way, ...