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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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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57 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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55 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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26 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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41 views

Does DC Ground Need to Be Stepped Down?

I'm pretty new to electronics and I have just a quick question about ground DC connections. If I have a device that is being stepped down from 12V DC to 5V DC does the ground wire need to be stepped ...
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52 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 ...
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66 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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77 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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76 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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3answers
51 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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255 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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91 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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26 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
40 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
74 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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74 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 ...
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2answers
193 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
47 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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57 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
208 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 ...
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2answers
160 views

Doesn't voltage on ground make it not ground anymore?

simulate this circuit – Schematic created using CircuitLab Beginner here, trying to learn enough to start using a microcontroller. If the I/O pins are internally high, wouldn't pressing ...
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2answers
68 views

Can current transformers be cascaded?

I have a GFI circuit that's part of an EVSE (electric car charger) that is known to work. What I need to do is be able to support testing for residual current on two pairs of conductors ...
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1answer
38 views

Grounds on an Evaluation Board

For testing purposes, is it ok to assume that every ground pin on the EV board is the same? even if not connected to each other explicitly? i.e. when using measurement probes is it ok to stick the ...
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44 views

USB datalogger ground read isn't zero volts

Im using NI DAQ USB 6008 datalogger. When I connect A0 (or 1,2 etc..) to ground in single-ended mode it gives 6 mV. Shouldn't it be 0 mV? Is it corrupted or normal?
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58 views

Arduino UNO not working with L293D

I am creating a simple robot that is controlled by an Arduino UNO, and given instructions by a button matrix. One can press 4 buttons for Forward, Backward, Left and right on on the matrix array, ...
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272 views

Using oscilloscope to measure voltage across a resistor

I have a board which is powered by a 5V PSU. I needed to measure the current flowing into the processor for computing power. Since there was no resistor that I could find in the path from the supply ...
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106 views

What is difference between Power-GND vs Pre-GND?

I would like to know the difference between different types of Grounds like Power-GND vs Pre-GND. Are all the grounds not same? Cant we connect the device to any one of these grounds? In my ...
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2answers
88 views

How much is a transformer's secondary floating?

Consider an isolation transformer with its secondary referenced to ground via a resistance R as in the following picture. simulate this circuit – Schematic created using CircuitLab If R ...
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2answers
116 views

DO we have to ground transformer?

I am using the transformer (a ballast), and its specfication sheet could be found here ballast specification. But on the data sheet, it doesn't says where we need to ground it. Usually, we would ...
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1answer
68 views

Switching Regulator Ground Moating

I have a DC-DC switching regulator that operates at switching frequency of 260Khz that steps down a 28vdc to 3.3Vdc. On the same PCB I have a microcontroller and would like to have it's ground plane ...
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60 views

Really weird AVR issue

So the other day I was changing some fuse bits on a 324p and screwed up. Well I set up a 88A to act as a clock out. Great. Well I went through 4 different chips, including a 48A, because of some ...
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1answer
53 views

Use a steel welding table to ground yourself from electrostatic discharge (ESD)?

I have a large steel welding table that I have been using as a work station to solder together my own custom PCBs. I have been using my anti-electrostatic discharge grounding bracelet and connecting ...
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1answer
82 views

Does Ground Voltage Need Lowered As Well?

I am dividing voltage of a 9V battery to 3V for a Rasperry Pi GPIO. I have the ground connected to the end of the resistors, so it is back to 9V when I connect it to the Pi's ground pin. Is it ok to ...
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163 views

Linked grounds produce “noise” on Arduino's 5V lines

I'm using an Arduino to realize two "simple" tasks. The Arduino shall receive messages by an 433MHz receiver and send them via ESP8266/ESP-01 to a server. The schematic/wiring plan is attached below. ...
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1answer
55 views

How to PCB layout WM7230 MEMS digital microphone?

I'm trying to figure out how I'm supposed to get traces to the four internal data pins of the Wolfson WM7230 Digital Microphone part. It's got a ground ring that is supposed to have a tight solder ...
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3k views

How grounding works to prevent electrical shock

Can someone please explain the how grounding / earthing to prevent a person from getting electrical shock using simple illustration of a faulty electric iron connected to the 240VAC mains? I don't ...
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2answers
110 views

Plugging in an oscilloscope in a land of non-grounded outlets

Background: I have only one outlet in my house that remotely approximates a proper equipment grounding conductor (it's bonded to the mains ground point via the armor of 50s vintage AC, which is better ...
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1answer
104 views

Arduino/Netduino: connecting a second power supply's ground to GND pin

I'm planning to play around with an addressable LED strip and a Netduino, and having read some tutorials I've learned that I will need an external power supply to provide enough current to the LEDs. ...
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1answer
228 views

should AC ground (earth) and DC ground be connected? [duplicate]

I have a power supply (AC --> DC) powering an microcontroller and DC electric motors. I also have the same AC powering a speed controller, which feeds to an AC motor. Should I be connecting the ...
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1answer
62 views

ESD Anti static mat Grounding and AC volts

I have an rubber ESD anti static mat on my bench that came without the snaps. I installed 2 snaps, one on each side of the mat. I connected the ground wire from the snap on the mat to the ground in ...
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1answer
95 views

Should vias be used for every GND connection?

When making a two layer board with the bottom layer being a GND plane, should every GND pad for ICs and passives be directly connected to the GND plane using a via, or should I route all of the GND ...
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67 views

DIY HV Tube Isolation Transformer

I am making a bench top tube power supply from salvaged transformers. I want to make it as safe as possible so I am checking here before the build. The two 120V/20V transformers have electrostatic ...
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2answers
91 views

Looking for a long-distance (~1km) physical layer

First of all, I have to say my knowledge on how networks work physically is limited. I am working on a project to interconnect farming equipment over fairly long distances, at a maximum of 1km, more ...
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1answer
186 views

LTC3355 backup DC/DC regulator output voltage sags under load in boost mode

Background For a hobby project I have designed a board using the LTC3355 DC/DC regulator to work as a power supply. I am a software engineer by trade, and I am thus totally underequipped to properly ...
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2answers
96 views

Where to connect frame ground

I have to offer a "FG" connection for the product I am designing. The product is isolated in many parts, so, which part of the circuit should i connect the "FG" to? Below is rough scatch of the ...
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2answers
51 views

Spark at the Probe's ground lead

In my set up I have a scope (high end Agilent scope), a PC with a USB port and Device Under Test. The DUT is powered from the USB port of the PC. PC and Scope is connected to the same power strip. ...
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2answers
655 views

Physically, how does connecting a PCB to chassis ground reduce noise?

I realize this may seem to duplicate Should chassis ground be attached to digital ground? but the answers in that thread don't explain why one should connect the chassis to PCB ground, aside from ...
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142 views

Can a digital multimeter damage a powered circuit when measuring resistance?

I wanted to make sure my ESD wrist-strap is in working order. So I tested like this: Connected the wrist-strap to household ground (via wall socket). Measured the resistance between the wrist-strap ...
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249 views

When does and when doesn't current flow to ground?

I was thinking about when current can and can't flow to ground. I came up with that current will only flow to ground when we have at least two grounds in the circuit, since then we have a complete ...
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1answer
30 views

Shorting wire from headphones

Im working on making a ultrasonic sustain pedal for a keyboard using an Arduino. I've looked up some tutorials on physical home made sustain pedals and it looks like you need to ground all the wires ...