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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op amp rails and it's inputs

I am trying to feed this voltage measured by the oscilloscope to a voltage comparator. by design the voltage should swing between +0.7 and -0.7 . BUT since the voltage is not referenced to ground i ...
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40 views

This circuit has floating nodes in LT Spice?

This is the circuit I'm working on. This circuit probably doesn't work as intended to begin with, but that's not the point. LT Spice keeps complaining that it doesn't have a reference to ground. I ...
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59 views

Which GND pin do I use on a DAQ?

I'm trying to use an absolute shaft encoder with an NI MyDAQ. I'm powering the encoder using the 5VDC pin on the DAQ. Does the ground pin--AGND vs. DGND--I connect the shaft encoder to matter? I ...
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39 views

Battery Wiring - 3 Independent systems with common ground

Background: Building a radio control wheel bot. Using a motor controller that recommends independent power supply for 1.) power to the controller and 2.) power to the motors. Also want a 3rd power ...
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65 views

When is an earth ground necessary?

For large appliances I usually see a 3-prong plug while smaller electronics will use a 2 prong wall wart with a DC barrel. When designing electronics, how do you know if you'll need an earth ground? ...
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35 views

DIY Ring Light: Grounding Bulbs in Series

I'm looking at making a DIY ring light using multiple fluorescent light bulbs. I'm in New Zealand and we get 230-240V and an current of 10A. I know from this I could rig up to 24 100W bulbs in series ...
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78 views

Why this nrf24l01 module has two VCC and two GND? [duplicate]

This module has two GND and VCC pins: However, this module and this module only have one of each. Why is that? EDIT: I know most MCU's have a lot of 3V3, 5V and GND pins. This is required for ...
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106 views

Why does the power company provide a neutral line?

I understand that power is often transmitted in 3 phases (with no neutral). Then, when we get to a certain substation, the power company basically gives house 1, L1, house 2, L2, house 3 L3, and ...
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294 views

Where exactly does the ground line go in an AC-DC power supply?

I'm working in the United States. I'm looking into working with mains power, and I cannot for the life of me figure out where the ground line connects. For example, a simple power regulator from mains ...
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56 views

PCB Integrated Chip Question

Hi I am building a PCB using eagle and its the first time I am using an IC. Two questions arose. Do I need to connect the IC chip's ground, because eagle did not do it? Do I need to make sure all ...
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22 views

Headset input crosstalk, or how to mitigate the effects of common ground resistance

I am building a cable to connect a guitar (or a piezo) and headphones to the TRRS connector of a smartphone through 4-wires cable splitting at ~1 mt from the connector. I am experiencing a ...
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40 views

surge protection — grounding in a slummy apartment without ground access [migrated]

I live in an apartment, where NONE of the outlets are actually grounded although they're all 3 prong... my landlord is a slumlord, fundamentally. He has fixed absolutely nothing electrical (lighting ...
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2answers
81 views

How to connect a bend sensor?

I've got bend sensors which I want to connect to analog inputs of an Arduino-board. Does it matter which of the headers I connect to the GND and which one to the analog inputs? The bend Sensors ...
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636 views

Why are caps configured this way in EMC filters?

Every EMC filter I've seen has capacitors between the AC lines and earth, configured like this: simulate this circuit – Schematic created using CircuitLab Why are the caps not configured ...
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2answers
84 views

Why are there so many connections to ground in some computer connectors?

I was surprised by the number of connections to ground some pc-related connections have. For example, the parallel port has 8: Also, the ATX power supply connector has 9 ground connections: Is ...
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1answer
57 views

USB shield shorts battery… protect the PC?

I'm making a retro-fit device (so I have plenty of parameters that aren't in my control) where we're adding USB connectivity to the device for use with a PC. The device is battery powered, and the ...
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2answers
342 views

Which Earth should a chassis be connected to: supply, or local?

I have a doubt regarding the earthing of an appliance and its separate isolation transformer. Consider the following simplified schematics; this is my first guess at which earth each chassis should be ...
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2answers
149 views

Is this pcb layout good practice?

I saw a PCB with something like this. A trace that connects the four holes on the corners. I assume that they do it to prevent some kind of noise. I am not sure if the connect that trace to GND Also, ...
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1answer
61 views

Decision on connecting Earth Ground to one of Two GND pins

I'm planning to design a board that is suitable for industry so EMC is so important. I have decided to use two separate power supplies(+5v and +24v) to Isolate the board from outside world. ...
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121 views

Should the unused areas on the top layer of my RF PCB have ground pours?

I realize there are some questions that are related to this topic but I didn't see any that are really RF specific. I am working on a 2-layer Bluetooth module and I have some unused spaces on the top ...
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217 views

What does pulldown resistor from Arduino's output pin to ground do? Is it necessary?

I came across the first picture below. But I am not able to find out how such arrangement is necessary or beneficial when you want to switch a load with an N channel MOSFET? Question number 1: Is ...
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370 views

Connecting a decoupling capacitor straight to the ground plane

I had always thought that if an IC is grounded to the ground plane then connecting a decoupling capacitor to VDD on one side and straight to ground plane on other side as shown below is acceptable: ...
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96 views

Designing an ethernet isolator

I'm trying to galvanically isolate a device which is controlled by ethernet (1000base t) via computer. I've been looking and apparently the ethernet standard provides some isolation, but after I ...
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53 views

Oscilloscope ground connection causing increase in current used

I did try to search for an answer, but may not know the correct terminology. Situation: Custom designed circuit board V-Reg 25V -> 3v3 + uC, LED's, POT, etc Powered by Tenma 72-8335 Power Supply ...
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24 views

Connecting a Random Ground Fixed the Circuit?

So I built an inverting Schmitt trigger with an op-amp with schematic shown below: The purpose of the circuit was to detect whether a mouse licks a feeding tube, and the feeding tube ended up being ...
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1answer
31 views

Linear and Switched-Mode Supply Common Shared

We have a mixed mode PCB system with both digital and analogue systems. Due to high speed they all share the same ground on the PCB, but use logical spatial separation to control noise. SO PCB input ...
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76 views

How should I wire up ground when using an ATX power supply to power an Arduino and several LED strips which in return are controlled by the Arduino?

Forgive me if this seems like a basic question but I want to make sure I wire these things up correctly. Currently, I have several LED strips that I am controlling with an Arduino and they are ...
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1answer
70 views

Eagle software: Different grounds in the same circuit

I'm designing an Arduino shield to manage the control signal that reaches 4 CCFL inverters. As part of the circuit design, I've decided to use optocouplers to isolate the Arduino's microcontroller ...
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1answer
57 views

Is that possible to create a virtual ground,for electrical purposes? [closed]

It might sound crazy, but I have seen many houses that doesn't supplied with electrical Ground (earth), and today there are many devices exist that need electrical ground. I know that some people ...
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2answers
114 views

Why use ground in oscilloscopes and what's the difference between it and a volte meter?

I am a high school student And we lately started studying rc and rl circuits And my questions are What is the difference between volte meter and the scope? Why we use the ground as reference in the ...
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2answers
88 views

Why is my body the path of least resistance during a shock? [duplicate]

I must say that electricity is hard to grasp conceptually. Just when it makes sense, you think hard about it and it all becomes confusing. When someone says electricity takes the path of least ...
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1answer
129 views

Why aren't vehicle mounted generators grounded?

To clarify, I'm thinking specifically of PTO-driven generators on fire apparatus. It would seem that they are grounded (Earth ground - not floating) when connected to a hydrant and their hoses are ...
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1answer
131 views

Unknown short-circuit between GND and ANTENNA pins of GSM module

I have a Quectel M72FA GSM module, brand new one. I have just soldered it onto my PCB and found that: there is a short-circuit between the GND and RF_ANT pins. This is the pinout: I have checked ...
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104 views

Two deep-cycle batteries connected in parallel by a single terminal

From what I understand, if two 12v batteries with different charge levels are connected in parallel with both terminals, the charges of the two batteries will even out. The one with the higher voltage ...
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0answers
28 views

Does the choice of ground/reference node influence the results found with nodal analysis?

I'm currently taking my EE introductory course about circuit analysis and I'm having some issue. I felt like I had finally understood how to (somewhat) properly perform Nodal Analysis. I attempted to ...
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1answer
75 views

floating ground for AC and DC power supplies

I wanted to connect two power supplies, one is AC (240V , 6A) and the other is DC (3,3V, 300mA). But i read in some referrence that connecting AC and DC power supplies could be dangerous if the two ...
2
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1answer
71 views

Multiple Ground Planes

I use a PCB mill to make my boards, and it doesn't etch off excess copper. I'm designing a breakout board for an RF tuner (400MHz), and I planned to have the ground plane on the top and the traces on ...
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2answers
110 views

How can I protect equipment plugged into ungrounded outlets?

I have an older house that does not have grounded outlets. Previously, I have used 2-prong to 3-prong adapters to plug in my equipment (which remove the grounding ability). I understand that this can ...
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2answers
79 views

Grounding a wire using a chunk of metal?

So I've made a complex LED grid and it works but has ghosting in some of the rows. I've given up trying to work out the reason why, but have noticed that when I touch the SCLK wire, or connect the ...
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63 views

Virtually grounded negative input op amp exists but no virtually grounded positive input. why?

If the positive input of an operational amplifier is grounded, the negative input is said to be virtually grounded and it has therefore zero potential. But the contrary is not true. A grounded ...
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275 views

Static shocks all over the building

I just came from the local library, it’s quite big, and most of it is made of an architectural design using mostly painted metal book shelves painted with some kind of anticorrosive paint along with ...
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2answers
152 views

What is the purpose of a turntable's ground wire?

Many turntables, such as the ever popular Technics SL-1200 mk2 have a separate ground wire which attaches to the chassis of the mixer or preamp you have your turntable connected to. It's also a ...
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1answer
27 views

Node voltage for simple circuit

This is probably a dumb question but I'm not sure what voltage is on this specific node. Also ignore values, they are random. Is it considered 0V or +V3? Then would the voltage drop of R1 be V2 or ...
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1answer
56 views

voltage regulator connected between positive and negative voltages

I'm kind of new to the world of electronics, so bear with me. I need to regulate +24 volts down to about +21 volts (for supplying a really pretentious heating resistor). I already have the circuit for ...
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1answer
108 views

Is earth of a 3-prong AC/DC adapter is connected to the GND of DC output?

Below is an illustration of a 3-prong AC/DC adapter(such as a laptop adapter): Here I marked the primary earth ground as 'a'; and GND of the secondary(DC) as 'b'. My question is are these grounds ...
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2answers
86 views

How to add ground to DC circuit?

I'm just a dabbler in electronic circuits and I'm really still kind of a noob. I am working on a project called the "Atari Punk Console" (Originally known as the "Stepped Tone Generator") but there ...
4
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2answers
267 views

Why do some electrical devices have a ground and others don't?

I noticed in my kitchen that the toast oven and the range hood had a ground fault, first by using a voltage detector pen, when getting near it the pen would activate from a distance (around 5cm ...
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1answer
79 views

Supply voltage of LM741 with Virtual Ground

I'm looking for a way to feed LM741 with a battery. I found this example that uses the TLE2425 to create a virtual ground of 2.5V (in the original example was used opamp TLC272): I simulated this ...
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2answers
71 views

Grounding a 30KVA isloation transformer

My company does audio visual services. When we use a single 120/208 VAC Three-phase "Y" power source for lighting, audio and video we get noise caused by the lighting dimmers injected into the audio ...
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1answer
221 views

Use indepenent power sources for Arduino and for breadboard

I am building a breadboard circuit to be controlled by Arduino. The circuit consists of about 20 bright leds simulating a vehicular lighting system (ten leds for headlight, 4 in taillight, 3 for each ...