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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3 answers
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Connecting 2 DC PSU -V terminals together for LEDs

I have a circuit which uses two 5 VDC PSUs to power a few addressable LED strips each and one is connected to an Arduino controlling them. Both PSUs are connected via the same 120 VAC input. I've ...
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0 votes
0 answers
60 views

Ground measure does not give 0 V in circuit [closed]

I am designing a circuit for signal generation. When I am probing the ground with an oscilloscope, I see a shift of around 20-50 mV (I measured it with two different devices). I would appreciate your ...
-1 votes
0 answers
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What is the acceptable ohmic value to ground on the primary side of a multi-tap 500 kVA transformer? [closed]

What is the acceptable ohmic value to ground on the primary side of a multi-tap 500 kVA transformer?
5 votes
1 answer
475 views

Why do we connect unused (always low pins) pins to GND through a resistor instead of connecting it directly to GND?

I have been reading the datasheet of RV-3028-C7. Everytime it talks about a pin that might be unused in a certain scenario (should be logic low), it instructs to connect the pin to ground through a ...
0 votes
1 answer
55 views

Use GND as V- in voltage regulator

For a circuit sensor, I need +15 V/GND/-15 V. My supply voltage is a single +5 V rail from a standard switching PSU. I looked at different voltage regulators and found, besides others, the ITA series ...
2 votes
1 answer
42 views

Ground loop protection watermark soil moisture sensor functionality

I am designing a little pcb where I want to read out impedance from an irrometer soil moisture sensor (example). The manufacturer describes preventing ground loops like this: Since WATERMARK sensors ...
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-1 votes
2 answers
102 views

If a circuit is electrons going in a circle, then would a wire to the ground lose electrons?

The electrons go to the ground and disappear? Does that mean the wire loses electrons? If not how do the electrons come back?
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1 vote
1 answer
71 views

Op-amp amplifier for Hall sensor: grounding

I built a simple LM741 non-inverting amplifier with a fixed gain of 3.1x and verified it works for a simple +0.3 VDC input on pin 3. It uses a dual power supply consisting of two 9V batteries in ...
3 votes
1 answer
66 views

Ethernet layout review: avoid vias or avoid copper under transformer?

I am designing a PCB that needs two adjacent Ethernet ports, both at 1Gbps speed. The first Ethernet port (J5) is broken out directly from the processor module (Raspberry Pi Compute Module 4). The ...
0 votes
1 answer
26 views

USB 2.0 fusing for protection

I'm reading about the ways to protect my electrical DIY projects that are power supplied by USB 2.0 cables (computer/chargers). Now...there are solutions for over voltage protection with diagrams that ...
1 vote
1 answer
72 views

Forcing current on capacitor tied to ground [closed]

I have a device with a capacitor tied to ground. If a negative current of 1 mA is being forced out of that pin, I am trying to better understand capacitor operation in this area. My questions are as ...
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2 votes
1 answer
40 views

Signal reference with common-mode filter on the power lines

What is the recommended way to handle the following situation regarding the control signals? Since the ground is separated with a common-mode choke between the source and the destination I'm thinking ...
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1 vote
7 answers
191 views

Why doesn't current flow to ground in some circuits? [duplicate]

Given the circuit drawn below, why doesn't current just go from the positive terminal of the battery straight to ground as in A. but, rather it goes round and round the circuit from the positive ...
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2 votes
1 answer
84 views

Level shifting not working properly - strange offset

12 sensor connected to an ESP32. Since the ESP32 works with 3.3 V and the sensor output voltage is 5 Vdc. I added a level shifter, in particular this level shifter mosfet. Basically I have: 12 Vdc to ...
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0 votes
0 answers
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ISO774x-Q1 Digital Isolator Grounding Isolation

I'm using TI ISO774x-Q1 digital isolator in my project. If I use GND1 and GND2 is the same GND, what cause it effect?
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0 votes
0 answers
66 views

Contact sensing between a rotating disc and a metal probe

So I'm trying to retrofit an existing PCB to be used for contact sensing. Apparatus: There is a disc rotating at about 9600 rpm. The disc is made out of metal with a coating of diamond dust on top - ...
6 votes
4 answers
1k views

How safe is this and should I change it?

I just finished building a project in my house to automate two plugs I installed on the top of my table, but due to laziness I left the ground connections outside the junction box like in the image: ...
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0 votes
2 answers
83 views

Earth wiring in an AC circuit

In this circuit there is a power supply source of main AC 220 V - 50 Hz and a load: There are two wires out of the main supply (neutral) and (live). The earth is connected to the neutral. If I am ...
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0 votes
0 answers
32 views

Power Plane arrangement on multi-voltage PCB

I am designing a PCB with 4 different voltages other than GND: PV+, 5V0, 12V0, VSYS I am trying to get out with a 4-layers PCB design. I have no particular high-frequency signals on the board (a ...
2 votes
0 answers
50 views

Where to connect case/USB shield to PCB ground?

I am currently designing a modular device for signal acquisition and signal generation. This is not a professional/commercial device. I am only building it out of interest and to learn. Nevertheless, ...
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0 votes
1 answer
29 views

Ground reference with DW01 and MAX17048

I have designed a project that includes a TP4056 with DW01 protection ic and porwer sharing feature. Now I want to include a fuel gauge and the only one I have found is MAX17048 I have readed the ...
0 votes
0 answers
86 views

Why is the ESP32 GND voltage different than the GND of the power supply?

I'm using a USB 2.0 hub to power one ESP32 NodeMCU. From the hub I'm also extracting the VCC and the GND (HUB->USB cable->Micro DIY female socket->VCC+GND). The voltage difference between the ...
0 votes
1 answer
42 views

WS2813 LED data permanently latching on power-on

I'm running into a problem where WS2813 LEDs 'latch' data permanently on start-up sometimes. The issue is sporadic, and random data is latched (RGB segments are enabled at random brightness levels on ...
0 votes
1 answer
102 views

Is 'grounding by chassis' achieved by the screws?

Sometimes a piece of equipment uses the chassis by grounding. Is it done through those screws that fix the PCB to the case? On a separate note, are PCB standoffs sometimes also used for this purpose? ...
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2 votes
2 answers
122 views

Crystal Radio Troubleshooting

I am learning radio starting with the basics, and I had a question about the behavior of my set up. I made a crude schematic below, the antenna is a 14 AWG random wire that I hung from a tree (using ...
-1 votes
3 answers
66 views

In a DC power-supply design, is it safe to connect the GND of the secondary side of the transformer to the AC input part?

This is a design that my colleague was using to supply power to some op-amps in an accompanying AC voltage measurement circuit. I'm wondering why the ground of the secondary side of the transformer (<...
2 votes
2 answers
75 views

ESD damage without earth ground

Can you explain how a totally floating PCBA (with semiconductor chips/ components stuffed, but no any connection to earth GND) is damaged by an ESD event from human touch? If human body is charged to ...
0 votes
2 answers
126 views

Two separate PCBs and common ground for UART communication [closed]

I have two separate PCBs. Both are powered by separate batteries. I want to communicate these two PCBs with UART. In some schematics, only RX and TX are used, while in others connections are made with ...
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0 votes
2 answers
134 views

Port expander with high side switch ground dilemma

I have a design wherein the basic idea is to control individual LED strings and dim (analog dimming) them using Pi Pico via I2C interface. This board is the LED driver which will be connected to the ...
0 votes
1 answer
63 views

Grounding sensors to large bodies

I've attached a diagram of what I'm talking about. I have a large (600x300x10 mm) aluminum block in which I place thermistors to monitor the temperature distribution in the plate (in a standard ...
0 votes
0 answers
33 views

Groundwater pump star-delta phase voltage confusion

Last time I got good answers for my question here so I came again today. Thanks. 🙏🙏 The problem am facing today is in star delta starting motor. When I connect motor to contactor, in phase to ground ...
0 votes
2 answers
94 views

2 layer PCB grounding

I have a 2 layer PCB that contains an ESP32, a LoRa module, a GSM module, some connectors to command relays and 3.3V & 5V power rails. My question is, should I set both layers as ground planes or ...
0 votes
1 answer
27 views

Eagle I can not change the isolete value of bottom Ground polygon

well this is my PCB design with Eagle Autodesk. Ground polygon looks perfect with Isolate value 0.8128 [mm] on Top. but this value can not effect bottom polygon Why? How can apply 0.8128 isolate ...
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0 answers
125 views

Isolating RF Ground is it wise?

I am designing a GPS module and I am planning to isolate the RF GND from the DC power supply GND with an inductor. I have chosen the Murata LQW18CN4N9D0ZD because the low inductance will have low Ldi/...
1 vote
1 answer
63 views

Chip antenna ANT161575ST-1202A1 layout question

I am designing a GPS module using the following chip antenna: https://product.tdk.com/en/system/files?file=dam/doc/product/rf/rf/antenna/catalog/rf_ant_ant161575st-1202a1_summary_en.pdf The datasheet ...
3 votes
8 answers
540 views

Why is the ground pin always connected to the "negative" power supply?

Please try to explain this in a way that I will understand. This is extremely frustrating for me. And try to explain where my confusion lies. I'll try to explain my frustration. Every piece of ...
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4 votes
2 answers
87 views

When to employ RF shield cover on PCBA?

During reparations and teardowns I have frequently come across PCB-mounted RF shields and covers. While I don't typically work with GHz processors or design RF modules I wonder if such covers could be ...
2 votes
1 answer
113 views

What can cause a surge in one 110 V line feeding a 240 V appliance, melting the connector?

One of the Hot wire (#10/3) going to my oven appear to have experienced a sudden very high in rise temperature inside the junction box, melted the connector, creating a contact with the face plate ...
1 vote
1 answer
106 views

Analog ground and pgnd in proteus

I am doing a project on proteus,I cannot find the ground terminal, where can I find AGND(Analog ground) and PGND in proteus?
-1 votes
1 answer
118 views

Made a mistake when Jumpstarting the Car

I made a mistake in connecting the cables for jump start. Instead of attaching one of the negative cables to the negative pole of the donor battery and attaching the other negative cable to a metal ...
1 vote
1 answer
85 views

Symbol for potentially dirty ground

I have a net which, although should be ground, could potentially be dirty and contain all sorts of minor noise. What is the correct way for me to denote this in my schematic?
0 votes
1 answer
57 views

GND related - maybe off topic

Situation - listening to music via Bluetooth using an integrated amplifier. I removed the GND wire from my pick up/turntable wich was connected to the amplifier. While removing it from the amplifier ...
0 votes
0 answers
43 views

Why is my buck converter stimulation not working on proteus?

Why is my proteus stimulation only outputting the voltage and current zero when I connect the ground terminal - shown at the bottom right of the image, when I do not connect the ground terminal the ...
0 votes
4 answers
189 views

Very confused about where "ground" is connected

I actually don't know that much about electronics, but I'm very interested in learning more. I watch Ben Eater on YouTube, and whenever he needs to connect the part of a chip to ground, he connects it ...
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0 votes
3 answers
135 views

Why do some electronics have two power/ground pins?

I was looking at the BMP280 temperature/pressure sensor schematics on KiCAD, and I saw that it has two power pins, and two ground pins. Why is that? Please let me know if more information is needed on ...
2 votes
1 answer
314 views

How to attach ground on a breadboard from a schematic?

I'm trying to build a circuit on a breadboard based on a given schematic, but I'm not sure how to "ground" components on it like how it is shown at node B: What I have done so far: What ...
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0 votes
1 answer
86 views

Why might my rack chassis have ground leakage?

I have a metal rack that contains a single item: A Samson S Patch Plus Patchbay. The patchbay is well isolated from the rack using nylon shoulder insulating washers, and I've thoroughly tested this ...
1 vote
0 answers
65 views

2 USB cable stripped wires vs black unstripped wire?

Here is my simple little project , I have bought these 2 very long cables, USB cables, but with time the micro USB side which you connect to devices has been damaged on both of them, the USB connector ...
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0 votes
3 answers
70 views

Adding ground to the minus of the source

I'm currently learning Kirchhoff's law and a circuit shown in the picture came up. I had tested it in a circuit simulator and no current was shown to leak to the groud. Could anyone explain what ...
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0 votes
1 answer
61 views

Connection between Analog GND and digital GND

While studying the following schematic I see that AGND and GND are connected with a 0R Does it make any sense? Why not just use a common GND? The 12V power supply input has a 100R resistor with an ...
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