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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90 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
25 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
45 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
130 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
116 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
65 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
36 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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1answer
43 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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34 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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1answer
177 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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2answers
74 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
71 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
110 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
62 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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0answers
57 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
44 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
75 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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1answer
115 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
45 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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6answers
2k 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
101 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
78 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
167 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
57 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
88 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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0answers
49 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
83 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
155 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
70 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
50 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
491 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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2answers
119 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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2answers
133 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 ...
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1answer
66 views

Physically sharing 5v and ground between multiple sensors

I'm using the Adafruit Trinket with two sensors that both need to be connected to power/ground pins (Trinket has one 5v output power and one ground). The final size of a whole thing matters so I ...
0
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2answers
43 views

Is a neutral back to main feed from satellite circuit box necessary if neutral is bonded to ground remotely?

I have a shed about 300 feet from my house. There is a circuit breaker box with two 20 amp breakers. Each breaker feeds a single 20amp outlet. Each breaker is connected to a #6 stranded wire that go ...
3
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1answer
57 views

Making conducted EMI measurements in the presence of building-wide ground-fault protection for personnel?

As is documented here among other places, the Line Impedance Stabilization Networks used to make measurements of conducted EMI as per CISPR 22, FCC Part 15, and suchnot contain large line-to-ground ...
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2answers
119 views

Oscilloscope measuring of PMT in photon counting mode

I have a setup as drawn below: DC source of 15V connected to high voltage (HV) source of 1500V connected to photomultiplier tube Hamamatsu, R1-R3 are resistors builtin the socket of PMT (there are ...
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3answers
230 views

Measure voltage difference between ground and DC floating power supply lines

110/220V AC to 12V DC switching mode power supply (metal enclosed, input is 220V with separate L,N and ground.) Measured voltage difference with a multimeter between V- and V+ 12V DC as expected ...
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5answers
620 views

Why does a sallen-key low pass filter not work with virtual ground?

I've been reading an article discussing single-supply op-amp design. Regarding Sallen-Key low-pass filter circuits, the author states that: A few filter topologies, such as the Sallen-Key low ...
2
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2answers
234 views

Transfer function of an op amp circuit

Let's suppose the following circuit: I am trying to find a relation between Vs, V1 and V2 at this circuit. Please note that Vs is measured in relation to the ground. I have declared some extra ...
0
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1answer
124 views

Get +12/-12VDC out of 24VDC Supply

I'm trying to use a single 24VDC power supply but rig it to give a heating coil the equivalent of 24Volts but at +12/-12 in reference to ground for safety reasons. Is this as simple as a voltage ...
4
votes
2answers
190 views

Should I ground an aluminum front panel?

I am building a power supply and it will be housed in a plastic case with a fan. I understand the wisdom of grounding a metal case, but in my case (no pun intended) I have an aluminum front panel. ...
4
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2answers
626 views

Why is earth used for ground? Literally earth?

Noob question: I never considered earth to be particularly conductive. It's just dirt, after all. However, I've seen "earth ground" conductive stakes driven into the ground in order for electricity ...
0
votes
1answer
51 views

4518 and Arduino

First off, disclaimer; I'm a computer scientist in the progress of my first baby steps in electronics. I'm trying to hookup a 7segment with a 4511, 4518 and an Arduino. The 45-series chips and the ...
0
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3answers
66 views

signal ground and power ground

I'm making a PCB with two ground signals, power ground and signal ground. These two shall be connected together at one spot on the PCB, after recommendations from the datasheet. But how is this done ...
5
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3answers
526 views

Does a Connector With Multiple GND Pins Make a GND Loop?

There are some cable standards that have multiple GND pins on the connector proper. A good example of this is the SATA connector (it has 3 of them). In reality, each GND pin has a slightly ...
0
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1answer
69 views

Where do I connect earth wire?

I'm trying to use this delay timer to control an exhaust fan. I have a 3 pin connection (with earthing wire) powering this fan and it works fine. If I have to insert this delay timer module in ...
0
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4answers
141 views

Ensuring common ground in a circuit with several voltage requirements

I'm working on a project that has components requiring various voltages. 3.3v --- to power a set of laser diodes (qty 24 @ 50mA = 1.2A) 5v --- to power a set of infrared transceiver sensors (qty 24 ...
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1answer
74 views

Monitoring power from 3-phase AC generator

Hello all. The above is a circuit schematic (sorry for poor hand drawing) for monitoring power from 3-phase AC generator. The main goal of the circuit is to see how the power output varies depending ...