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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19
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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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7answers
8k 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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11answers
4k 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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4answers
2k 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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5answers
6k views

Any downside to using a charge pump for an op-amp negative supply

Background: I'm often building audio op-amp circuits for various purposes, and for small projects usually prefer single "wall adapter" supply. So for a ground reference I'll either use a simple ...
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5answers
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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 ...
5
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1answer
649 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 ...
4
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2answers
2k views

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 ...
4
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2answers
1k views

Virtual earth (ground) or “mid-rail generator”

In a recent question I (rightly or wrongly) said in a comment that calling a mid-rail generator (two resistors and a smoothing capacitor) a "virtual ground" was wrong and that the term "virtual ground"...
4
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2answers
1k 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 ...
3
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1answer
2k views

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 ...
3
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3answers
84 views

Operational Amplifier - Virtual ground

In the question above I was asked to solve the general shape of Vout, and the exact values in t=0.5ms,1ms. My question is - can I approximate a constant virtual ground in the negative input of the ...
3
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1answer
223 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 ...
3
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4answers
2k views

How to make a simple negative power supply

I want to experiment with amplifiers but I need a negative power voltage source. I looked for some circuits but as far as I found they either are not simple & reliable or require an IC. Is there ...
2
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7answers
2k views

Op-Amp Integrator's virtual ground

I have been using op-amp TL072C in charge integrator configuration. R = 1k Ohms and C = 100 uF. Vin is a DC signal of 1 V. VCC = 10 V and VSS = -10 V. I get the expected output which is VSS, when a ...
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2answers
526 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 ...
2
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3answers
662 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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1answer
164 views

What does this rail-splitter-like circuit do?

I'm repairing an audio amplifier for a car. It has a switching supply that generates +/- 50V rails from the ~12V battery. In the output section of the amplifier, I found this small circuit with ...
2
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2answers
366 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 ...
2
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1answer
188 views

Transistor getting hot in rail splitter circuit

I designed and prototyped the circuit below. The circuit works as expected but Q2 is getting really hot during operation. I simulated it in LTSpice and saw that Q2 draws more current but the range is ...
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0answers
2k 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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3answers
145 views

What is the difference between real ground and virtual ground in opamp?

I understand what a real ground for a Opamp is.It is a terminal which is physically connected to ground or earth which acts as the reference point for the entire circuit. But what do we mean by a ...
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1answer
454 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
1k views

Using ground vs virtual ground in a single-supply Sallen-Key low-pass filter

This is the filter in question (courtesy of Wikipedia): The opamp supplies are +5 V and 0 V, and I'm already using a buffered 2.5 V reference elsewhere in the circuit. I'm debating whether or not to ...
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1answer
108 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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4answers
2k 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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2answers
492 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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2answers
664 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
1k 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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1answer
32 views

Virtual ground supply for audio-applications

The most common solution to provide positive and negative voltage to supply an OP-amp would be to use a voltage divider and another OP-amp. In this way the voltage "on the top" of the ...
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3answers
72 views

Differential amplifier and different ground

I am designing a circuit to measure the voltage across the output of buck converter. With different ground for the buck converter and the micro controller, with respect to which ground will the ADC ...
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1answer
52 views

Connect a DC/DC converter to a virtual precision ground in KiCad

I'm trying to design a circuit which steps up 5V to 12V using a DC/DC converter and then use a virtual precision ground TLE2426 to split the 12v to +/-6V. I'm using this design in KiCad: I'm having ...
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1answer
119 views

What causes a voltage drop at the input of this TL082CP Op-Amp?

I am breadboarding a circuit using a TL082CP Op-Amp, and I am reading consistent values with the multimeter. The Op-Amp stage is powered with a single 9V battery, like this: The Op-Amp stage looks ...
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1answer
85 views

Understanding current sourcing and sinking in TL2426 rail splitter

I have a 40dB active bandpass filter being powered off a single rail power supply with the TL2426 providing a virtual ground so I can get a dual power supply configuration. Currently, I'm having ...
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1answer
458 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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0answers
60 views

Should I connect metal enclosure to -V or to virtual ground?

I've built a headphone amplifier powered by a switch-mode 2-pin wall wart power supply. Internally a virtual ground is created by dividing and buffering the supply voltage. Input and output signals ...
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0answers
197 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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0answers
478 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
2k 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 ...
0
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3answers
366 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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2answers
246 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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3answers
304 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 ...
0
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1answer
246 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
292 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 ...
0
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2answers
409 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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3answers
897 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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1answer
67 views

Virtual ground vs voltage reference

I want to know what is different between voltage reference and virtual ground and can you use both of it as rail-splitter in transimpedance amplifier, if not why. All I know is Virtual ground chips ...
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1answer
73 views

Two power supplies with different current in series

Does the schematic in the picture work with these powersupplies from China? Both are rated with 5V but one with 20 amperes and the other with 2 amperes. https://www.aliexpress.com/item/33042313383....
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1answer
76 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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1answer
1k 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?