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Questions tagged [virtual-ground]

In electronics, a virtual ground (or virtual earth) is a node of a circuit that is maintained at a steady reference potential, without being connected directly to the reference potential.

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Voltage Balun 1:1

somewhere I have seen that it is possible to build a Balun by using a transformer in the following way: The explanation I have found is that the fact that the ground is only at the primary coil will ...
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1answer
36 views

Is it right to define ground as a pool of surplus free electrons, like a metal?

In a dipole antenna or any other pole like antenna, there is supposedly a ground on one side causing the current to flow away and towards the ground towards the feed, but if the whole antenna itself ...
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2answers
138 views

What is the correct schematic symbol to use for virtual ground?

I'm following the design of a circuit requiring a power supply to provide something the author calls virtual ground, \$V_{gnd}\$. The circuit look like this: However, I'm using KiCad for the design ...
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34 views

Driving an XLR input with virtual ground

I am building an audio circuit. I would like it to have XLR as an input (as well as others). It needs at least 12 Volts to operate. To drive my operational amplifiers, I am using a rail splitter with ...
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1answer
63 views

What happens if output voltage is connected to OPAMP operating in negative feedback? [closed]

simulate this circuit – Schematic created using CircuitLab I need to anlayse state of OPAMP for V1=1V ,10V ,15V ,40V Its not ptractical problem just want to learn what happens if a voltage ...
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1answer
59 views

Creating Neutral node on Three phase Inverter

I want to create a neutral node at the output of a 3-phase Inverter for ACIM. Is it possible to do that by adding 3 resistors at the Inverter outputs and join them together to get the neutral node? ...
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1answer
87 views

Single supply opamp colpitts oscillator

I'm designing a Colpitts oscillator with a single supply rail-to-rail opamp powered with 3.3 V. The positive input of the opamp is set to VDD/2 to offset the negative part of the oscillations so ...
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7answers
4k views

How make a dual +-12V supply from a 24V SMPS

I'm trying to power a home-made load cell transmitter using a 24V single SMPS. I need to make +12, 0 and -12 Volts that are capable of 50mA. I wish to power multiple channels of opamps and bridges. I ...
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2answers
447 views

Virtual Short Concept in an Op-Amp

By virtue of the open-loop gain being infinity for an ideal op-amp, the two input terminals are said to be virtually shorted. Yet, the virtual short concept is only applied to op-amps in negative ...
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3answers
156 views

Voltage gradient across an antenna (and how it drives an AM radio)

Edit: I was interested how is voltage gap maintained across an antenna. It seemed to me that an antenna might be like a wire where if there's a voltage at the top, the same voltage would be at the ...
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1answer
77 views

Op amp AC simple supple (Buffer) LM324N

I´m working on a proyect and i use OrCad/Spice to simulate the op amp that i gone use and my Voltage(output) signal is Constant and my Voltage(Input) is sinusoidal.
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1answer
43 views

transimpedance op-amp wrong and random output

from my previous question (this link) i advised to using operational amplifiers to converting current changes to voltage changes then i followed the standard circuit for a transimpedance ...
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0answers
72 views

Would a current feedback op-amp work well as a precision ground reference?

I've been looking into precision ground reference circuits to form ±5V rails from a 10V supply for a project I'm working on, and noticed that current feedback (CFB) op-amps have some desirable ...
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1answer
166 views

How to connect this amplifier to my symmetrical power supply?

I am relatively new to electronics. I have this power supply. It is symmetrical because I need negative voltages to other parts of the circuit. The power supply input J3 receives 18 VDC. The 7806 and ...
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1answer
105 views

Trying to build a symmetrical power supply from a VDC input without the problems of virtual ground

I have built this circuit to supply a few ICs. The problem is that at some point in time the load on the positive site is bigger than on the negative side. So the virtual ground moves towards the ...
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1answer
78 views

As I increase the volume of this amplifier the sound gets choppy and the negative power supply regulator gets hot as hell

I have designed and built the project below. Open the image on new window or imgur will not let you scale it up and you will not see the components. This is a 4 channel stereo switch. You press the ...
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3answers
910 views

Power Supply negative voltage as ground and ground

I have a PC PSU and can get GND +5V +12V +3.3V and -3.3V -5V -12V out of it. I need to power a device that needs more than 12V. Am I able to take the -5V as GND and connect +12V to VCC and still use ...
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4answers
966 views

Isolating audio ground between devices

I'm planning a build for a guitar amplifier with 2 stages, the first being a tube pre-amp and the second stage being a solid state amplifier. Both amplifiers will be powered from the same source, a ...
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3answers
166 views

What is the meaning of “ground” and “-V” in a simple push-pull circuit?

In this simple "push-pull" circuit, there are +V, -V and ground connections. up until now, i always considered ground to be the minus side of the battery. but that is also the way i understand -V, so ...
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1answer
540 views

How to calculate capacitor and resistors on virtual ground circuit?

How do I calculate the resistors and the capacitor on this circuit, which has ground and virtual ground as you can see? In the second image, how do I find the current I2?
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1answer
94 views

Signal Filter Shunt to GND or Virtual GND

In the following two circuits, I am using a TLE2426 as a low impedance virtual ground to bias multiple single supply opamps/diff amps. At the output is an LRC filter, but I'm not sure whether to ...
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1answer
115 views

Use of virtual ground to split ground loops?

So I have a "broadband" signal (DC-5MHz) which I'd like to send over coax cable to two other circuits referenced to the same ground. Simply floating the other two circuits is not an option for ...
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1answer
267 views

Using an interface and virtual ground with a non-isolated power supply

If I use the above rail-splitter with a 24V non-isolated power supply, what can be the problem when used with any load like an opamp ect.? How would the current loop if the power supply is not ...
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4answers
1k views

Operational amplifiers and virtual ground

Could you physically clarify why we use virtual ground in op amps? I have seen the argument that since A(open loop gain) tends to infinity, we need the difference in inputs to tend to zero(to maintain ...
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1answer
69 views

Does my electric clearing field actually make ions?

I am using an electric clearing field of 15v/10cm (~150V/m) to remove ions from a test chamber, however I'm wondering to what extent the localisation of the field's reference voltage plays a role. ...
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1answer
569 views

Problem in using a buffered virtual ground as opamp split supply [closed]

The single-ended to differential converter on the right side works fine in sim only if I set opamp rails Vcc=12V and Vee=-12V as split supply. But if I supply the circuit by using 24V supply and a ...
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1answer
278 views

What is behavior of this virtual ground circuit when sourcing/sinking current?

simulate this circuit – Schematic created using CircuitLab This is the virtual ground circuit from a battery-powered headphone amplifier(direct link to schematic PDF). What is the behavior of ...
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1answer
381 views

JFET Burn Out in Wien Bridge Oscillator

I have a simple Wien Bridge Oscillator (with JFET gain control) circuit pictured below. This circuit works as expected at lower voltages (+/-9 V), but I am running into some problems with higher ...
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0answers
992 views

Why do some audio amplifiers connect the power ground to the signal ground?

Trying to add a MIDI synthesizer & speakers to a keyboard here. Here's the schematic: simulate this circuit – Schematic created using CircuitLab But I was getting annoying crackling and ...
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2answers
601 views

Simple single-supply op amp virtual ground questions

I found this circuit online and made it and it works. It uses an LM358 op amp to amplify an oscillation from a 555 in astable mode. simulate this circuit – Schematic created using CircuitLab ...
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2answers
320 views

Virtual AC ground for AC power main

I have the following problem: I use to perform electrical experiments in a small room in an apart where other persons repair computers. It sometimes happens that I make the main differential switch ...
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11answers
3k views

Virtual Ground Paradox?

I'm unable to come to terms with something I think is a paradoxical situation relating to the virtual ground of an Operational Amplifier.Please pardon me if this is a really stupid question. When the ...
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2answers
253 views

How to split 5V USB input into 4 rails (+/-5V, +/-15V)? Problem with combining two virtual grounds

Problem: I have 5V input from USB, I need to split it into four rails with +/-5V and +/-15V. Currently done: I have built the following circuit in a breadboard. I have measured the outputs with a ...
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2answers
296 views

Sensing voltage with respect to virtual ground

I want to sense a near-ground voltage in this circuit which is Vsense, but its maximum voltage would be 0.5 V so I designed an op amp amplifier with a gain of 10. I used another op amp to split the ...
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0answers
367 views

V+, V- and GND - Getting started with virtual grounds

I've been happily playing around with TTL logic but have recently come across an Analog / Digital converter TSC7106 whilst tearing apart an old thermostat which has demanded V+, GND and ... V- :o I ...
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3answers
542 views

Two grounds when using transistor switching

Background I'm designing a small circuit in which an MCU and all its peripherals should be shut down unless a certain condition is met, which is represented by a switch in this simplified schematic. ...
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1answer
781 views

Proper biasing to virtual ground with TLE2426

I've made simple circuit - it attenuates the signal 10 times, bare bones voltage divider: simulate this circuit – Schematic created using CircuitLab Now I want to bias the signal to half of my ...
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2answers
702 views

DC to DC power supply Virtual Ground circuit dillema

I am trying to power a circuit with two op-amps that require multiple voltages. The voltage requirements are -14v, +14v, ground/24+. I am trying to power this circuit from a 12vdc power supply. I am ...
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3answers
634 views

Can I use one voltage divider to bias multiple points in circuit?

I have 4 nodes in my circuit that require virtual ground of half the power supply voltage. 2 of the nodes are just offset for input signal and other 2 are for op-amp biasing to virtual ground. Can I ...
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2answers
465 views

Driving LM386 with signal referenced to virtual ground

I'm working with a chip that outputs audio signals to headphones that are referenced to a virtual ground. Since I'm connecting the audio signal to a speaker instead of headphones, I'd like to ...
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1answer
785 views

Phantom Power Circuit Comparison?

I'm going to connect an electret mic (WM-61A) to my computer's "mic in", and am very confused on the reasoning behind a couple different diagrams/schematics that could possibly be used to do this with....
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2answers
231 views

What does it mean for a signal to be 5V with respect to one leg of an AC input?

This power supply provides 5V with respect to one leg of the 24 VAC input. I'm trying to understand what that means because this provides 1.2 amps and I only need 20 mA for what I'm trying to do. It ...
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5answers
2k views

Battery and virtual ground

I have a 24V battery and I'm trying to obtain a virtual ground from it. 90% of the circuits I found limit themselves to an opamp, which has very low current sinking. I'm trying to add a pair of ...
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1answer
619 views

Measuring opamp output voltage (with virtual ground) on arduino

I have been working on a simple project to read the analog voltage input on Arduino. I'm having problem to read the correct value on Arduino. I know what's causing the problem. I'm using the virtual ...
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1answer
312 views

Design of variable split rail power supply

I'm attempting to drive an array of piezo transducers and am struggling to find a good design capable of driving from around +-5V to +-30V at about 2A for my testing. There are about 12 sets of ...
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4answers
2k views

What is the use of an op-amp whose output and inverting input are connected to ground?

I am in first year of Engineering school and I was given an assignment containing this circuit, which drives pressure sensors in a pitot tube : I am struggling to understand the whole circuit, and ...
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1answer
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Op amp rail splitter virtual ground shifts when LED is on

I have a 9V power supply. I split it in half using a voltage divider buffered through a TL071 op amp. I use the +4.5V rail to power an ATmega328P. The microcontroller has one pin attached to an LED ...
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3answers
577 views

Bipolar output from DAC with unipolar supplies

I want to use a unipolar 12-bit DAC (MCP4725) as a function generator with bipolar output (from -2.5 to +2.5V). Problem is, I only have two supplies of +5V and +12V referenced to the same ground, so ...
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3answers
370 views

Phototransistor with virtual ground opamp design

I am setting up a high sensitivity light detection circuit and came across this thread just a bit ago: Phototransistor transimpedance amplifier Within it was a response with this image: My question ...
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2answers
399 views

How do I connect the virtual ground as shown below

This is a circuit for EEG. How do I make the connections labelled as Virtual Ground? Also, how do I connect the 1M trim pot in the top right?