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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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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63 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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30 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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78 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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81 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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49 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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46 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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326 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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85 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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85 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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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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61 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 ...
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40 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 ...
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44 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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73 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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83 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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394 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 ...
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178 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 ...
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101 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 ...
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185 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. ...
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354 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 ...
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39 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 ...
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59 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 ...
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509 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 ...
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60 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 ...
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74 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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45 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 ...
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78 views

How to detect current imbalance?

I would like a circuit that detects current imbalance between two conductors. The currents are normally equal and opposite in direction, but can vary in time (or reverse direction). Neither ...
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99 views

What's the purpose of the ground plane?

What's the purpose of the ground plane? I guess it's a pretty basic question and I tried to understand it by reading http://en.wikipedia.org/wiki/Ground_plane#Printed_circuit_boards but I still don't ...
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65 views

Am I going to encounter grounding issues with this PCB design?

This is my first time designing a PCB, and because it is part of a project at uni I have the intention of manufacturing it afterwards. The circuit itself is a voltage-controlled oscillator designed ...
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758 views

What is the difference between different types of GND

I would like to know the difference between different types of Grounds like AGND, SGND, Battery Gnd, PGND. Are all the grounds not same? Cant we connect the device to any one of these grounds?
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52 views

Do I need a ground plane?

I'm a noobie in pcb designing, so i created this one single sided board, do i need do add a ground plane if I have a ground trace? Cheers!
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67 views

Arduino in Ground-Chassis (Vehicle): Activate by grounding

I am working with an Arduino as a controller for an Aftermarket Heated Seats Kit and interface for the stock A/C Auto Control Panel (the car did not come with heated seats, and I acquired an A/C Panel ...
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54 views

What is ground on a circuit that uses AC?

Below is a circuit diagram for a circuit that runs off AC voltage. Where do I connect all of the points that connect to ground? Do I just connect them all on the same rail of a piece of Vero board? ...
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129 views

Why does the GND of the Arduino oscillating as well?

I have an Arduino Uno and what it does is simply output an oscillating signal of 1 MHz on PIN11. I measured the signal using a oscilloscope and a probe with a ground clip. First, I connected the probe ...
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232 views

What are Vcc and GND on a shift register?

What are Vcc and GND on a shift register? I thought that I had to provide a positive voltage to the IC via the Vcc, but turns out that I can operate my shift register without powering the Vcc. ...
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593 views

Why is this resistor connected between connector shield and ground?

I was looking over my raspberry pi model B and I noticed a resistor between the USB power connector shield and ground. I've noticed this on many PCB designs with much larger packaged resistors ...
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67 views

Metal connector case connection when using a plastic housing

I'm designing a board with 2 SFP connectors and I am not sure what I should connect the cage pins to. The manufacturer recommends connecting the case pins to chassis ground but my product is in a ...
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104 views

Connect multiple grounds to one external connector in Eagle

For my project I've designed 3 power supplies, 1 5V, 1 3.3V for the supply of the micro controller and one 3.3V for 3 INA 226 shunt monitors. I do have some questions regarding the ground. de power ...
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84 views

Current Leakage calculations regarding shock hazard. A complete picture?

There is a quantity called current leakage which has always confused me. By reading various definitions, it seems to be the current flowing through the ground circuit of a device (whether this be an ...
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91 views

Connecting devices powered by separate SMPS without common ground

I have a power over Ethernet design using the SI3402 PoE PD chip to generate 3.3v for a pic 18F67J60. The switched mode voltage converter in the SI3402 is a little unorthodox in that it switches Vss ...
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3answers
251 views

What does short to ground mean? How to do that?

I've just started a simple project using raspberrypi and a capacitive touch sensors breakout board. I had a few problems using I2C, but after some time of research I managed to get stuck on one ...
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244 views

Floating supply and USB ground

I have a somewhat complex circuit controlled by an Arduino, which is supplied by a self powered USB hub (earth grounded 5V supply). A part of the circuit has to be powered by 12-20V DC. When I plug ...
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74 views

Can we consider that ethernet or RS-232 (RS-485) networks have no ground connection between the two ends of each cable?

This is for a huge home theater. I have a power transformer that converts 380VAC between two legs of a 3-phase power system down to 230VAC, with a center-tap of the secondary being our "neutral" for ...
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82 views

Switching Power Supply makes speakers hiss

I have a computer with a 5.1 soundcard, that I'm using to run a standard PC 2.1 setup (Corsair SP2500) on the main audio output, and two rear surround speakers I had laying around. The speakers in ...
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1answer
92 views

Power Mosfet design issue

My schematic The components BSN20 is a N-channel enhancement mode field-effect transistor (datasheet) IRF7416 is a HEXFET power MOSFET (datasheet) This is a part of a project in which the line ...
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61 views

Voltages with an earth ground

In this diagram, from what I understand the voltage between the positive terminal and the first earth ground is \$ 0V \$ and the voltage between the negative terminal and the earth ground is \$ 0V ...
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1k views

Why is the chassis used as ground in automotive electrical circuits

Automotive electronics generally use the metal chassis as the negative ground connector for the DC circuits. Obviously this saves something on wiring. Is there an electrical reason for this approach? ...
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78 views

Connecting grounds of a disconnected power source?

Background: I'm designing a portable appliance (24 DC, ~30 amps, air conditioner) and need to have a switchable power source between vehicle-supplied power (alternator) and a separate dedicated ...
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186 views

Noisy Voltage Rails (Vcc, Gnd) - Noise Isolation for Automotive Circuit

I have an audio (mic, speaker) circuit that I am currently powering off of a 12V car adapter that is fed into a 10V switching DC regulator to power the rest of the circuit. I have noticed a horrendous ...