Questions tagged [earth]

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What is the impact of Earth's magnetic field polarity on consumer electronics?

Earth's magnetic poles are known to have inverted in the past. How are commonly used circuits or component of consumer electronics (from energy production/transportation to TVs, mobile phones and PCs) ...
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1answer
61 views

Oscilloscope and Electrical Safety

I was reading an article in a magazine in which the following sentence is written about a circuit that generates a certain waveform on a load R (in which one of its terminals is connected to the earth ...
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0answers
38 views

What do the white and green colours on the earth leakage CB denote?

I've come across two 4 pole earth leakage circuit breakers, one with the all green lever and another with white levers for phases and green for neutral. Is there any special meaning to this? I've ...
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3answers
74 views

Power Supply Earth for Bench Testing

I work in a typical electronics lab, with resistive earth mats, ESD straps and isolated DC power supplies to test prototype PCBs. I prefer not to use the power supply earth-ground, and to leave the ...
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3answers
87 views

I thought that the ground was different from “earth”! [duplicate]

According to Paul Scherz in his Practical Electronics for Inventors, he mentions in Chapter 2, Theory, the following: Typically, the earth, with its infinite charge-absorbing ability and net zero ...
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3answers
65 views

Electrical Standards - Earth Wire at Low Voltages?

I got a question about safety standards: I'm designing a consumer device and I'm not sure whether I need an earth wire. I have an AC-DC converter plug that outputs 5 V and up-to a maximum of 1 A ...
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2answers
76 views

Live wire and ground question

I am trying to fully understand the danger of AC voltage but still I have some questions... I understand that human body has a capacitance that facilitates AC current penetration. I also understand ...
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0answers
42 views

between earth and ground

In my 100 Watt ACI Drive circuit, I've confusion about which components will be best to connect between DC_Bus Ground & Earth? FYI: 300 VDC for Motor & 15 VDC for Logics & other ...
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1answer
99 views

Why am I reading 22VDC / 69VAC when measuring between myself touching a MacBook and ground?

If I put the positive probe of my multimeter on earth, and touch the negative probe with my hand, while another hand is touching the metal surface of my MacBook, I get around 22VDC or 69VAC. I cannot ...
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0answers
44 views

Earth ground and return path [duplicate]

During a fault, how does current flow through the earth wire when the earth wire has no return path? Doesn't the earth wire in earth grounding terminate at a copper plate located deep underground, ...
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8answers
5k views

What is the right way to float a home lab?

I just got myself some new toys for my lab at home like 30V DC power supply, KKmoon signal generator and a Rigol DS1052E. I want to float everything, because I don't want to spend any money on stuff ...
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1answer
29 views

Do the dipole antenna edges have earth potential or is it a closed circuit made of co-axial cable?

I understand the shape of the dipole antenna, but how is it fed so that the current only flows through one direction during the half cycle? Even in a normal pole antenna, is there a ground at the edge ...
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1answer
89 views

Motor / VFD / Protective Earth

I have little experience with AC motors since I'm majoring in Mech.E. My team is setting up an AC motor with a VFD to control the movement of an airfoil inside a metal cage we built. I understand the ...
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1answer
76 views

SMPS electrical noise issue

1I'm using class 2 medical graded SMPS in our device. So earth connection not recommended. When connecting SMPS to load (contains capacitive touch LCD), touch function is affected by SMPS noise. When ...
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3answers
35 views

Connecting the Block AIM 5.0/2.0 auto-transformer to UK three-wire plug

I am not electrically very knowledgeable person. At the moment I am trying to connect a Block AIM 5.0/2.5 Auto-transformer to a piece of very sensitive medical equipment. The auto-transformer was ...
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2answers
61 views

How to insulate DC from earth noise while keeping it referenced to it

I have an AC/DC converter (220 to 24) inside an electrical cabinet. The 0VDC is referenced to earth, like this (couldn't find a symbol for an AC/DC converter in the schematic editor so I made a dirty ...
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3answers
74 views

Earth Fault in a TT Network: Current loop, or charges flowing from one grounding to the other?

There are serveral things I (yet) don't understand about the T-T-earthing system. The most important one is that I don't understand which way the the current takes in case one of the conductors (for ...
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4answers
241 views

Floating Source Voltage Difference to Earth

I was reading about floating voltage on web but there is something that I couldn't understand. I attached photo of circuit. As you see it shows 60v difference between neutral of flating source and ...
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1answer
432 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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1answer
68 views

PE pin position

I have one question. I'm designing a PCB which is a sort of smart switch (so, basically, you have one 230V input and one 230V output, where the output and the input share two wires, N and PE, and the ...
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1answer
162 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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4answers
972 views

Is the link between the earth/chasis terminal and the utility transformer established through a dedicated wire or the soil?

I was following a tutorial on power supply transformers and at the very beginning I have encountered the following illustration: I added the names TG and HG for the LV transformer ground and the ...
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1answer
158 views

How to convert high voltage DC at low amps to low voltage DC or AC at high amps?

How to convert high voltage 500 volts DC at very low amps to lower voltage 12 volt DC or AC at high amps? Must I use an electrostatic motor or can I use an op amp? The reason I am posing this is a ...
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1answer
104 views

Why is earth at 0 V with respect to phase?

In 3 phase transmission lines we have different voltages depending on how we measure it. Phase to phase voltage is going to be 1.73 times more than phase to neutral. So far I understand everything ...
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0answers
47 views

LED lamp lighting with only 1 pin connected to earth which isn't connected to anything

Anyone can help figure this out? Yesterday, while connecting my LED lamp projector with an AC plug, I noticed when one of the 2 pins was connected to the earth pin of my AC extension cord, it would ...
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1answer
130 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 ...
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1answer
72 views

x2y caps and common mode chokes (using both)

I am designing a ultralow noise PCB board. Common mode noise has to be minimized, so I have a question I am planning to use a CMC on power input and to further decrease the common mode noise I also ...
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1answer
312 views

Ground and earth layers on PCB

I am designing a digital board with USB input and output. Shield of USB is connected to a chassis ground as per USB specs and connected to GND through a R and C in parallel USB power has a common ...
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2answers
114 views

Questions about earth grounding enclosures

A text mentions about the importance of connecting the earth wire to an instrument case/enclosure as follows: Instruments with ungrounded cases can become lethal devices in the event of ...
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1answer
117 views

Amplifier does not sound right when balance is centered

I have an HK 590i amplifier. When the balance is centered sound is like coming from far away (voices). Sound is good only when balance is full left or right. I researched the site and found this ...
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0answers
81 views

No grounding system available for oscilloscope, what other options are available?

Many old buildings/houses in Europe are so old that they were not built with a grounding system. I happen to live in one were this is the case. The problem is that if I want to use an oscilloscope, it ...
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1answer
91 views

Why is it dangerous for human being to touch one of contacts in AC wall outlet? [duplicate]

Let say we have some DC voltage source which produce some voltage which I will label as V. Let also say that we have some real bulb which is supposed to work when voltage V is applied across its ...
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10answers
27k views

Why is main's neutral tied to earth?

My dad is an Electrician and I myself am an Electronics Design Engineer, and to this day he still hasn't been able to give me a good reason for this. Consider the two following pictures/situations - ...
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0answers
465 views

Converting an ATX power supply to bench power supply.

I'm planning to convert an ATX power supply to a bench powersupply. It came to my knowledge that the DC ground is actually connected to earth. As I understand, this might become a major issue if I ...
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0answers
614 views

Potential difference between DC floating power supply and earth ground

I have a question about a simple DC floating power supply: it is as simple as possible, secondary coil -> bridge rectifier -> filter cap, as shown on the figure below. If I connect the input of the ...
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1answer
232 views

Modding a Class II switch mode power supply to have output dc- shorted to earth

As above, what are the disadvantages, risks and dangers involved in modding a class II switch mode power supply i.e. a double insulated laptop charger that is ungrounded to have the dc- output shorted ...
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4answers
418 views

Tiny shock from 230V AC?

So first at all this question isn't really about electrical engineering, but about electricity in general. However, I think this is the best place to ask, correct me if I’m wrong. Also I’d like to ...
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1answer
263 views

Earth ground to dsub9 shell

I have an enclosure containing an earth ground line. It has a brass earth ground bus that is connected to: the input earth pin of a 120V single-phase mains IEC320-C14 connector the output earth pin ...
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4answers
2k views

Neutral and the earth are bonded at the main panel or the substation but why is only earth wire used for safety?

Typical distribution system can be illustrated as: Here are my premises (and assumptions): 1-) Chassis in a house must be connected to the earth, not to the neutral. 2-) The earth and the neutral ...
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1answer
124 views

Op. Amp. read variation when Earth is connected with Signal GND

I've made this simple circuit to read the line voltage (the 1 pin is conected in a uC by a resistor): In the image NEUTRO is Mains Neutral AC, FASE is Mains Line AC and TENSÃO is the signal to the uC ...
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2answers
296 views

Clamping the output ground very close to earth ground

I've noticed that the output ground of most power supply are not quite the same as earth ground. The DC is nearly negligible, but there is usually an AC component between output ground and earth ...
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0answers
35 views

Is it possible to detect and filter noise on an earth?

I ask because I have a solar array on my house with micro inverters. The monitor (an Enphase Envoy) no longer detects the the inverters. Troubleshooting suggests noise on the earth, perhaps caused by ...
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2answers
1k views

Grounding without Ground

My system use only line and neutral connection from mains (no ground.) Inside this system it is converted to 5V using SMPS. My enclosure is metal, I need to ground this enclosure. Since I do not ...
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2answers
6k views

Are countries that use 2-pin plugs less safe than countries that use 3-pin plugs given that the earth is missing?

Will there be occasions when using 2-pin plugs is safer than 3-pin plugs? Is it accurate to say that 3-pin plugs are always safer given the presence of earth?
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2answers
3k views

Should I connect a cable's shield to the ground layer of board when it's isolated from earth?

I have a controller board powered by DC that may or may not be isolated from earth ground. The chassis of the device is non-metallic. This board connects through a long (30-40m), shielded cable to a ...
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6answers
836 views

Is 'grounding a desktop PC via 1MΩ resistor' unsafe when working inside the case?

Activity: maintenance (installing/replacing hardware parts, like motherboard, CPU, DIMMs, graphics cards) inside an ATX case. Goal: ESD protection and user safety. Original question: Is 'grounding a ...
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4answers
2k views

Resistor or low impedance path between common ground point and mains earth?

A simple EPA (ESD Protected Area) consists of 3 things: wrist strap antistatic mat common point ground Wrist strap and antistatic mat both should grounded to the common point ground. ANSI/ESD S6.1 ...
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2answers
984 views

Why are laptops grounded to earth via 1E6 ohm resistance and desktops not?

I measured a few laptop AC-to-DC adapters. 1E6 ohm between GND pin (goes into the laptop) and earth prong (into the wall). Desktops are grounded directly to earth: 0 ohm. Why this difference?
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1answer
122 views

ESD damage due to earth potential drop?

When lightning strikes or the earth wire (from the wall outlet) suddenly gets charged negatively for whatever reason, then, in theory, can it cause ESD-damage to a PC? Because the grounding wire (...
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4answers
954 views

Antistatic mat instead of antistatic wrist strap?

Just to make sure, before doing something silly: can i place a 2nd antistatic (dissipative) mat on the floor (along the 1st mat on the table) and stand on it with bare feet? Instead of wearing an ...