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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.

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How do you monitor communications on a positive-grounded device from a negative-grounded desktop?

I have a need to read the signals being sent between two boards in a lighting fixture. In preparing to do this I have read much about the chips, RS485, and analysers/decoders that are out there. I am ...
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43 views

Amplification of a Microphone with a LED Array and speaker: Grounds? [on hold]

This is the circuit I'm trying to build: Circuit on falstad.com I feel like everything works in theory, but I'm having trouble implementing the grounds on the actual circuit. I do not know where to ...
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46 views

Shield grounding location for an STP cable in a balanced system

If a balanced source or driver is coupled to a differential balanced receiver via a balanced STP cable as shown in the hand drawn illustration below: in such case I have read that grounding the ...
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1answer
43 views

Common ground on a switch mode power supply

I've got a switch mode power supply and I have a question on the grounding of the PCB. Documentation on the PSU can be found here: https://docs-emea.rs-online.com/webdocs/1621/0900766b81621ef9.pdf ...
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1answer
51 views

Proper Chassis Grounding

I'm starting to design things that run off mains voltage and I want to be sure that I have a proper connection from my chassis to earth ground. I've been reading a bit about proper grounding and have ...
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33 views

Grounding the components of a DIY cnc machine

I'm in the process of building a DIY cnc machine. It already runs, but I noticed it has some interference problems (steppers act weird on occasions, the full graphic smart controller LCD has trouble ...
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1answer
584 views

Why put capacitor between ground and chassis?

In the product I analyse (an optical fork sensor, rated 10V-35V), there is a sizewise big capacitor between ground and chassis. I measured its value with an LCR meter, it is 60nF. I also broke one by ...
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35 views

DC floating ground and TVS Diodes for ESD

I want to provide ESD protection for a low voltage battery powered device and I do not understand what sort of net I should attach to the cathode side of the TVS diodes: I do not have a strong ...
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161 views

Shield in Inner Copper Layer

I have been designing second version of 4 Layer PCB. The PCB has connectors all over the PCB. In the first version, I had Copper Pour (I call it ...
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2answers
66 views

Not Understanding Grounding in an Electrical Circuit

This might be a stupid question but i am just a little confused about grounding/earthing. Specifically for example in a home when some electrical appliance faults, the current will go to ground since ...
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1answer
50 views

Can leakage current to ground generate static electricity?

I'm having a weird issue at my workplace where some industrial equipment is present. Almost every time I leave my laptop (with grounded aluminum body) for a while and come back I will get a quite ...
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1answer
53 views

Device's ground riding on a non-ground signal

The question is somewhat conceptual, feel free to close if it's too off-topic. If I take my portable (battery-powered) oscilloscope and try to measure the mains voltage, the connection polarity ...
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29 views

Digital signal integrity & grounding

I have a battery operated device with an old B&W LCD in it. I'm tapping to the display bus and would like to input it into an FPGA for some processing. The bus includes vertical and horizontal ...
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1answer
61 views

Earth Ground Portable Generator

I recently bought a pure sine wave 2kV portable generator to use for camping. In the manual it states that the generator should be grounded to actual earth through a metal stake and then attached to ...
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1answer
79 views

Noise on my oscilloscope when probing a wire

I am prototyping a NTC voltage divider circuit and I am having trouble with noise on my probe. It seems like I am constantly getting a large amount of noise (200-300mv) on my oscilloscope waveform ...
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2answers
168 views

Ground something, for a short time

I need some simple solution, for grounding an AdKey for a short time lets say 200ms, only once, on each power on. I don´t know the exact needed time so it would be nice if i can change the time with ...
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40 views

Why doesn't current leak to ground (DC)? [duplicate]

In the circuit shown below, I am considering ground to be ideal earth ground (stays at 0V no matter how much current it absorbs). It is my understanding that current flows when there is a potential ...
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3answers
75 views

Sensor damage, ground loop or something else?

We are testing an capacitive fuel level sensor in field. Its mounted on top of a heavy construction vehicle (colmar) with a 24v battery system. Our sensor runs for few weeks and damages. Every time a ...
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39 views

Odd Ground/Power(?) issue with Mixing Desk - alternate grounding?

I am a bit stumped with this one. Unfortunately there are a few variables involved, but I will do my best to ask an answerable question.... I just built a DIY synthesizer. It functions absolutely ...
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1answer
43 views

Question on Ground/Neutral connection for a 220V equipment

I sketched the following schematic from a motor controller board that has to be operated at 220V from L1 to L2. The earth wire is connected to the chassis of the machine. Where I live, it's common to ...
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97 views

How to line a Metal Melter secondary for higher safety

A Metal Melter is a kind of home-made low voltage (less than 40 volts, mine is 3v) welder (small-scale) made from a microwave oven transformer (MOT). I left the primary intact (the thicker wire, which ...
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1answer
43 views

Power supply and pcb connections to ground, earth

I am planning a pcb which is powered by two switching power supplies LRS-150F-5 (230 V/AC to 5 V/DC) LRS-150F-12 (230 V/AC to 12 V/DC) . The power supplies are mounted in their own metal box and the ...
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48 views

How to safely connect USB to TTL (FTDI) adapter to device and also use bench power supply?

I'm trying to flash new firmware onto an ESP8266EX chip. The chip requires 3.3v and 80 mA (average). My USB to TTL programmer (FTDI chipset) can supply 3.3v but only at 50 mA. Here is what I'm ...
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62 views

Measured continuity between live and neutral

I was trying to get rid of the humming noise coming from my speakers in my hi-fi system. It is an old piece of equipment from back when the UK appliances did not come with the mains plug and you had ...
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1answer
48 views

Is this soldering iron and power supply combo grounded and if so, how?

I'm interested in a TS100 soldering iron as a decent starter iron and a light one that doesn't take up too much space. It doesn't come with a power supply though, presumably to keep it flexible as it ...
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90 views

Flyback Transformer - Grounding the Ferrite Core

Today I dismantled (I hope this is the correct verb) a flyback transformer. The thing that I've never seen is that one end of one of the windings is "glued" to the ferrite core (Before you ask; yes, ...
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1answer
92 views

Do I definitely not want to to add a ground wire to this UART connection?

I'm in a bit of a quandary here but it must be a common one. I have two boards powered from the same battery through a "Y" cable; both boards have voltage regulators on-board. These boards are ...
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1answer
35 views

Separate ground for gate opener control box?

Is it worth electrically isolating the control box of a gate opener from a well grounded steel fence? Or does the grounding of the fence have the same effect? My house is in a very lightning prone ...
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3answers
97 views

Why does low power factor make my LED bulb and clock radio flicker at 0.2 to 3 Hz?

[California, USA, regular 110 V power.] I'm reading the power factor of my "Late 2013" 27-inch iMac using a P3 P4400 Kill-A-Watt. It reads 0.95 when operating normally (60 to 120 W), but when ...
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68 views

PCB Grounding Plane Review

I am reviewing a 6 layer board that has analog signals on the left and right side of the board. I have always read that analog circuitry should be grouped together for easy plane segmentation. ...
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1answer
60 views

Can a ground fault be caused by something outside the home?

Yesterday afternoon, I had a GFCI switch trip. It would not reset. I figured I had a ground fault. I left the home for a few hours and after I returned I was able to successfully reset the GFCI. The ...
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3answers
70 views

where to place grounds on a circuit

I'm used to seeing circuit schematics with single/no grounds at all (drawn by teachers and some tutors) but now, I see circuits with multiple grounds. My question is, when drawing a particular ...
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2answers
463 views

What is the purpose of this extra PCB pad?

I am looking to use this crystal in an upcoming design and I am a little bit confused by the datasheet. The datasheet is available here: CMR200T Datasheet This is the image in question: Question: ...
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1answer
48 views

Analog ground/Digital ground question

I am designing a four layer PCB, (signal, ground, pwr, signal), which is to generate +-1V max 30kHz frequency signals which is output on a differential pair. It is pretty simple board layout but I am ...
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1answer
38 views

Why is there a grounding clip on this solder sucker instead of a third prong on the plug?

As most of these inexpensive tools tend to omit the ground altogether (such as in soldering irons), why would ground be added as a clip instead of a third prong? Is there an advantage for it to be ...
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118 views

Crossing ground planes with low current low frequency signals

I have a board which has two ground planes, analog and digital, that on this board are completely separate. The grounds connect on another board, which is connected via a flat cable. All signals on ...
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1answer
165 views

Grounding and Signal Integrity of my PCB Layout (ADC, SMPS, SD card, USB)

I am currently designing a battery monitoring system for an 8 cell lithium battery pack. I originally made the device using a STM32 dev board and breadboard, with an SD card to log data. The system ...
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1answer
88 views

How can charging current be understood intuitively?

The charging current I’m talking about would be the one between un-shorted phases and ground when there is a short to ground in one of the phases in a distribution network or facility. I'm not talking ...
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2answers
57 views

Will this SOI circuit be grounded?

Upfront, I apologize if this may be a terribly obvious question. I don't have all of the background to understand it confidently. I'm trying to apply a voltage for an electrophoresis experiment ...
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1answer
82 views

Why is the usb shield always tied to ground (GND pin)?

The shielding on a cable is to avoid interference from the outside world however it is always tied directly to the GND pin. Not inside the cable itself but inside a device. Every single device I take ...
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38 views

Preventing the voltage between two isolated grounds from exceeding max rating

Consider the low-side current sensing application shown in Figure 1. Grounds 1 and 2 are galvanically isolated. Assume, for example, ground 1 is the NEUTRAL line on mains power (\$V_g\$), and ground 2 ...
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3answers
76 views

Can current flow to earth in TN-S Earthing system?

The above illustration of a TN-S Earthing system shows one shared connection to earth between neutral and protective Earth. Assuming a short circuit occurred, in the brief second before detected by a ...
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3answers
124 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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2answers
49 views

Is grounding necessary for a re-purposed laptop charging brick? [closed]

If I have re-purposed a laptop power brick, is it important to ground it or in certain use cases could one get away without earthing the power brick? I bought a class D amplifier board off eBay ...
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1answer
49 views

What to do with internally unused pins on a non-programmable device?

I'm designing a board for using the FLIR Lepton 2.0 LWIF camera (datasheet at https://www.flir.com/globalassets/imported-assets/document/lepton-engineering-datasheet---without-radiometry.pdf), and ...
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0answers
102 views

Correct way to do “power injection” from multiple DC supplies?

I'm using a PixLite controller to run a bunch of pixel LED strips. Since I'm sticking to 5V I need to use multiple power supplies (PSUs) to "inject" extra power for the number of LEDs I'm running. ...
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1answer
215 views

LTSpice chassis ground or earth ground

I'm trying to simulate a circuit for a design I'm making. In a few parts of what I'm interfacing with uses relays that when closed will short a few power supplies to the chassis ground and in LTSpice ...
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1answer
96 views

Measuring soil resistivity and estimating soil equivalent resistance in a long distance

I'm trying to size the Neutral to Ground resistor (NGR) in the Wye of a 138 KV to 4160 V Delta-Wye Transformer. In order to find the proper value I have estimated the charging current of the system by ...
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1answer
19 views

MAX31865 RTD converter will it acccept only floating inputs?

We intend to use MAX31865 for measuring resistance values. Since MAX31865 is RTD to digital converter, kindly clarify whether the MAX31865 will accept only floating inputs or it can be used with ...
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1answer
74 views

“Creating” a ground pin for my laptop

I am building a sensor using an Arduino connected to a laptop; I noticed that the readout is much more noisy when I use a non-grounded laptop (either running on battery or connected to a power socket ...