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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53 views

What is the maximum resistance that is allowed when connecting two grounds in a 5V unit?

Say I have a 5V Arduino and I want to connect two grounds (I don't have another idea of anything else I would like to short). How good should the conductive between them be? For example if I want to ...
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36 views

AC-Current to ground without a closed circuit?

I'm struggeling with the idea that there needs to be always a closed circuit for current to flow. The theory is that there shouldn't be a voltage drop across C2 and R2 and no measurable current at AM1 ...
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1answer
140 views

Should a grounded case have voltage across it?

Ok so simple question though it might seem stupid. I'm wiring up a simple metal enclosure with a control unit inside. AC current from the wall, 240v~ to the unit. I'm containing it in a metal case ...
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188 views

Why do French power sockets have a protruding ground?

French power sockets have a protruding ground. Why did they make this decision? I can't see any major benefits from it, it saves some pennies on each power cord, but it exposes the ground connection ...
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36 views

Establishing common ground between attiny and 24v motor, and between attiny and 12v logic circuit, without connecting 24v motor and 12v logic grounds

I have a coin hopper which has a 12V logic circuit and a 24V motor. It also has 2 brass plates which sense the amount of coins in the unit, one plate has high voltage, and second has low. These plates ...
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1answer
133 views

How to deal with ground in VCCed-chassis device?

I'm restoring old USSR radio receiver ("Okean-209"). I've already resoldered all electrolytic capacitors so audio amplifier works great again (there was very low sound before that). However, there are ...
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2answers
59 views

Extending an RF ground plane outside a small PCB

I am making an RF PCB with a surface-mount antenna on it. It is a quarter-wave antenna, so the ground plane should also be as long as a quarter wavelength for good RF performance. For example, a ...
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2answers
74 views

Ground on power supplies

Why the power supply plugs of some modern electronic equipment have ground and some other ones -- with the same power, same manufacturer, same purpose -- don't? For example: I bought 90 Toshiba ...
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2answers
95 views

Making a 'graph-like' circuit schematic

I would like to make a parallel circuit with two resistors to most-closely resemble how a 'graph' would look, for example: However, when I try doing something like this in Everycircuit it fails (...
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0answers
32 views

Understanding ground to earth and neutral, trying to make my home safe [migrated]

I've been reading for hours and still confused in regards to my situation. I'm trying to improve electrical safety in my house, especially with a growing family. Any help would be great. I'm ...
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36 views

Ground Fault Protection In Consumer Electronics

Medical devices have to meet ground fault/isolation requirements such as 60601-1 (link). Particularly galvanic isolation is required on power and data lines to avoid a fault conditions that could ...
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1answer
101 views

What does voltage mean on a ground wire? (Neon-lamp screwdriver)

This question has some implications on home related work with mains. Never take what you read on the internet as the truth when lives might be in the line. That is how I'll be treating potential ...
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3answers
98 views

What does 'ground' look like on a breadboard?

Given the following circuit: What would this look like on a breadboard? For example, what is 'ground' on the right? Is there a particular 'component' that can be used in a breadboard to act as ground ...
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1answer
122 views

Power Latching Relay off/on in response to 12V ignition and 1 second ground pulse

I have the following sample schematic of a 12 volt automotive circuit to trigger about 60 seconds of power output to a latching relay on output pin 3 of the 555 Timer chip. The schematic below is a ...
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1answer
78 views

AC to DC power supply - earth ground capacitance on DC output

I have a mains to 60v DV power supply that I’m using for a project. Needless to say it managed to give me a bit of a shock. This surprised me as it’s supposed to be floating. With no load the power ...
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1answer
64 views

Closed loop circuit vs open loop circuit can current flow?

So this has been bothering me. Lets say we have a circuit which looks like this below: If the connection to ground is earth ground, and the positive side of the voltage source is connected so there ...
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1answer
69 views

Current flow with a potential difference

I have a small question, I am trying to wrap my head around the different types of ground connections in electronics. For earth ground connection In an earth ground connection electrons can sink to ...
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68 views

How to prevent common ground circuits messing with each other

I made an Arduino based 18650 battery tester that has 4 identical circuits that charge and drain. Testing one battery at a time gives one set of results which I deem to be correct but testing more ...
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5answers
17k views

Difference between the following two very basic circuits

What is the difference between the below two circuits? I know the bottom circuit has 'ground', but what does that mean exactly? Why would someone want to construct the second circuit over the first? ...
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1answer
45 views

Sharing a single ground wire across multiple RTDs

Consider the following, simplified schematic for a single, two-wire RTD sensor: simulate this circuit – Schematic created using CircuitLab The two wires from the RTD sensor plug into pins 1 ...
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2answers
66 views

How to make sense of the signal trace of differential signal

I am trying to understand following signal trace picture that is shown on the wiki page of 1553 Bus. The Bus has balanced differential pair wires. As the 1553 bus has differential signals on the ...
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1answer
81 views

What is the reason for multiple ground connection and multiple testpoints on this PCB?

Please, have a look at the image: The biggest pad at the top is the negative terminal of a battery holder. Through 0 Ohm resitor above it goes to a capacitor across a DC motor (not shown). Below the ...
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6answers
11k views

In this transistor circuit, what is the purpose of the diode across the motor?

I am trying to follow an Audrino tutorial with my kid and I am confused by the role of the diode in this circuit. In particular, I have the following questions: It looks like the circuit will work ...
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27 views

NodeMCU - Are all GND connctions born equal?

I'm designing a PCB which is based on NodeMCU board in its core. On NodeMCU there are some GND pins, most of them are to serve digital outputs/inputs, or external sensors which operate on 3.3V. Vin ...
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4answers
2k views

Should I ground the heatsink?

I am using an npn transistor in TO-220 package, and its collector is electrically connected to the metal part on it. I have checked it via a multimeter. I use a heatsink for that transistor, with ...
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1answer
55 views

Is there a rule of thumb for choosing polygon width?

I am currently using the same width as the smallest wire inside the polygon, is this too small?
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1answer
47 views

Ground offset or common mode noise voltage

This is just a small doubt I would like to clear. Suppose I have a buck regulator providing output at 5V and 1A. Suppose I measure the output voltage at the ground pad of the output capacitor and it ...
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1answer
33 views

BQ25570 Ground Layout

I am using the BQ25570 power management IC for energy harvesting from a solar panel. I am currently designing the PCB layout for the IC, and I am a bit confused about the ground. As you can see in ...
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2answers
118 views

KiCad net tie on inner layer

I'm making a 4 layer board, with ground on one of the inner layers, as usual. I would like to keep the digital and analog grounds logically separate, although they of course connect on the PCB, and ...
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1answer
76 views

Ground loop problem in op amp circuit

I am having problem with a few millivolts of ground loop in my single channel amplifier circuit when I ground the input (pin 1 on socket, - input of op amp). I am using INA121 instrumentation ...
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1answer
129 views

Isolated Modbus (RS485) ground and UART noise

I build an isolated RS485 (Modbus) interface board for a sensor. I use ADM2682 as transceiver and VAQE6W-Q24-S12-D as isolated DC-DC converter. All is managed my a STM32L412. There is 2 interesting ...
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1answer
85 views

Why does my MCU work better when powered to Vcc and PA1=D2 instead of Vcc and GND?

I'm making a MIDI processor, with its power coming ... directly from the MIDI signal itself, as done by the author of this page (see "Powered by MIDI" paragraph): it works well with a 100µF cap. I ...
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1answer
69 views

Is shared ground necessary?

I ask this mainly for curiosity and am not trying to make shortcuts for real projects. I have a couple of devices (mcu development boards) that connect to each other using various communication ...
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2answers
60 views

Why do some switching regulator ICs have single VCC pin but multiple PGND pins?

This is a follow up question to Reason of multiple GND and VCC on an IC I found a switching regulator IC (buck) that has multiple PGND pins and one analog ground (AGND). It has only one VCC pin. (...
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1answer
28 views

Connect GND/signal-output-pins to differential-input-pins

I have a device outputting a signal (-10V...+10V) referring to GND. Now I want to feed this signal into another device, that only accepts differential inputs (-10V...+10V). Is it possible to just ...
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1answer
45 views

AD7606 PCB Layout - separating Analog and Digital grounds when no dedicated pins are present?

The AD7606 (and all variants thereof) is an excellent simultaneous-sampling ADC. Simultaneous sampling is necessary for my application. However, this ADC, unlike many others, does not have separate ...
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2answers
89 views

ADC / data acquisition board - general layout question

For one of my current projects, I am designing a small data acquisition board. However, I am currently not sure about the overall layout of the board. Here are 2 possible variants I came up with. ...
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2answers
95 views

Trying to pull down 1.2V Dataline to GROUND, Does not fully drop to 0V

Im trying to pull down a 1.2V dataline to 0V with a STM32 development board (H743ZI). The impulse is only some nanoseconds long, about ~50ns (longer duration or constant: does not matter same result.) ...
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1answer
31 views

Ground with one sensor vs multiple sensors

I'm pretty new to the world of electronics and was working on an Arduino project using load cells and HX711 amplifiers. The project consists of four HX711 connected to the Arduino and Pi, with all ...
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38 views

Why can not add GND in EasyEDA Simulation mode? (This circuit does not have GND. Please select GND from the circuit tool to add to the circuit.)

I want to test my circuit but for start i can not get simulation from one simple circuit, when i click  the GND icon i cannot add that to my schematic and only the mouse cruiser showed like this: and ...
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50 views

Confusion about GND and PGND

In a digital circuit like a cell phone. If a switching ic has it’s reference point as PGND, separate from the main GND (4v Main vcc coming from battery), but they’re tied together, then What exactly ...
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1answer
55 views

Is Vout in this circuit loop-grounded when Vin becomes 0V?

I don't have expertise in this area. So any answer or instruction would be helpful to relieve my pain. I think Vout would lose its GND when Vin becomes '0V' because C is located before GND. Am I ...
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1answer
51 views

Ground wire appears live despite not being connected on either end

I have decided to add another plug outlet near an existing blind outlet box. Unfortunately I've found that the existing one doesn't have ground since it's an old building, but that's a problem for ...
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1answer
66 views

How can I ground the external shield of the USB cable?

Currently, we're trying to carry out electrophysiological recordings from the mouse brain using Open Ephys acquisition box and a silicon probe, and we are suffering from severe noise in probe signals. ...
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0answers
51 views

Ground offset test

I need to perform a ground offset test. Ground offset = 1V Please tell me whether my approach is correct. Typ Input power supply to the circuit is +12V Typ Load current for the circuit is 0.5A So, I ...
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1answer
46 views

Ensuring 'common' ground on my devboard : powering externally, + JTAG + VirtualCom with USB

Before I ask, I did see other similar posts, but it's not easy for me to apply them (I'm not an experienced EE..). My question in brief is, how to get common ground, to avoid potential gremlins. (Or, ...
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4answers
457 views

Is a ground connection needed in between master and slave for this RS485/422 scenario?

I will work on a small project where an SSI-output data (angle data) of a rotary-encoder will be read by a micro-controller board (such as an Arduino board) and the micro-controller will then send ...
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2answers
96 views

Ground loop- Why would current flow between 2 earth grounds when signal return path offers the least impedance?

Lets say I have 2 ICs- C1 and C2 acting as driver and receiver for the digital signal. The signal is transmitted through a conductor/cable ( 2 wires) as shown below. I have 2 doubts 1. What would be ...
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0answers
62 views

Ground Planes, 0v or GND?

I have a board that has a dual voltage isolated DC-DC converter on it. The converter takes 0 an 5v in and gives -5,0,5 v out. The 0v of the input is actual ground. Most of the PCB uses the isolated ...
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1answer
43 views

Reading of megohm during ground check

During the check of pins on connector with a multi-meter, one of the pins that goes through the relay to provide ground signal, I am getting 8MOhm (8 megohm). I should not be getting anything on that ...

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