Questions tagged [floating]

A voltage that is not connected by any conducting path (including resistors) to ground or the key voltage reference point.

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4
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1answer
386 views

How do actively driven mosfets or transistors react to floating source?

Attempting to add some lights to a car's "intelligent" lighting system. Want to make sure I understand how my n-channel mosfets will react to losing their ground, while their gates are still connected....
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1answer
179 views

What does floating source mean in this context?

What makes the load in the below circuit floating?: Does that mean the load does not have a ground shared with the circuit ground?
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50 views

No unconnected inputs yet ICs (logic gates) still seem to yield erratic/odd behaviour

I just finished building a 4-bit adder on a breadboard and I am experiencing some quite odd/erratic behaviour and I am wondering why. The actual circuit/logic works as intended, meaning the 4-bit ...
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3answers
226 views

Understanding Differential Mode Voltage of a Floating Circuit?

I am currently trying to work on studying for the ECE NCEE FE exam, but I came across the problem and don't quite understand the answer. Essentially we have an ideal transformer with an arbitrary ...
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2answers
801 views

Turning off op amp for low power application high side or low side

I have a design where I am using a LM324 to act as a buffer (unity gain impedence transformation amplifier) to feed the voltage from several high-impendence voltage dividers into my MCU's ADC pins. ...
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1answer
150 views

Floating Nwell schematic and introduction in a MOS switch

My classmate told me using a mos (body connect drain)as a switch may have leakage current,because there is a parasitic diode in that MOS,so there will have a leakage current.so i have to connect the ...
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1answer
294 views

HSPCIE Default Value for Float Nodes

I have M inputs. I want to connect m of them to Vdd and leave other nodes floating. I know that in real experiments the floating nodes can get any value between 0 and Vdd. I was wondering how HSPICE ...
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2answers
134 views

Floating Differential measurement?

Can I simply hook up an opamp inputs, (either using a differential or in-amp topology that is/are also powered from a floating power supply), across a device under test that itself has exceeding ...
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37 views

What is the correct way to bias a floating instrumentation amplifier?

Im designing a voltage measurement circuit that needs to measure differential signals in the order of mV in the presence of high voltage common mode noise. Im using a isolated DC/DC converter that is ...
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1answer
462 views

How do floating voltages affects circuits/systems?

I was at a talk recently regarding robustness testing. It was separated into parts: Uncontrolled and Controlled. Uncontrolled involved applying high floating voltages to various pins and logging the ...
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2answers
134 views

How to get rid of floating voltage on Bridge rectifier

I'm trying to implement a rectifier and AC voltage sensor. The rectifier part works just fine. I'm able to power my device without any issues. Please look at C2 in the screenshot (Circuit schematic)....
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2answers
137 views

Why is this capacitive circuit not working in both multisim and LTspice

The voltage at the top most node of this circuit should be the average of the input voltages. Vtop*CT = C1*V1 +C2*V2 +C3*V3 where CT = C1+C2+C3 I get 0V instead. UPDATE Thanks for the help. I ...
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2answers
72 views

Floating input pin with external pull-up

I would like to improve the performance of my push buttons, which sometimes don't respond when pressed. They have external pull-up resistors and have been initialised as floating input pins. Does not ...
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2answers
105 views

Floating analog input of ADS1115

I am using an ADS1115 as an analog to digital converter. R2 and C2 are used as a low pass filter. I have used two schottky diodes as voltage clippers to protect against over voltage. To avoid ...
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3answers
55 views

Floating traces on MCU dev boards bad for noise?

When you have development boards for microprocessors with every GPIO pinned out on headers around the edge of the board, is the board more susceptible to picking up noise than a board without all ...
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3answers
70 views

How does a pull-down prevent a “false 1” in a pin?

yesterday I asked a question about pull-ups and pull-downs and resistance in an input pin, but I feel that the question that invaded me today is different from my yesterday's post so this is why I'm ...
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2answers
106 views

Floating battery negative terminal [closed]

I am building a circuit that uses an op amp comparator stage to control the circuit shown. The op amp circuit will switch on or off the transistor to drive the motor supplied with a set of AAA ...
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0answers
64 views

Floating Simulated Inductor

In the image below, I do understand that a grounded inductor can be simulated using op amps. However, to make a floating simulated inductor, I have read some posts that said two ground simulated ...
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1answer
27 views

Floating Nodes Error in Simulation in ORCAD PSPICE

Does anyone have any insight as to what exactly is wrong with my circuit on Orcad/PSPICE? My name is in the project name so I blurred it out for obvious reasons
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18 views

Battery powered device - How to measure external floating differential voltage

I have the following task. As depicted in the sketch, I have a battery powered device which needs to measure the differential voltage VIN between two external nodes, EXT_NODE1 and EXT_NODE2. It is not ...
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1answer
56 views

What is the result of 1 and float on OR gate?

If only one input is 1 into an OR gate, the output is 1, but does that still count if there is no input from other sources? (like float) Or is the output simply float as well?
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1answer
186 views

multiplexer with floating outputs

I have actually a solution based on a multiplexer (CD4051) which drives 8 outputs, either at 0V or 3.3V (the input is at 3.3V). Each output of the multiplexer drive a NMOS and the goal is to have a ...
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1answer
97 views

Why does my ungrounded DC power supply work?

This is a question about electronics theory that I haven't been able to grasp. I was testing a stepper motor wired like the following: https://learn.adafruit.com/adafruit-tb6612-h-bridge-dc-stepper-...
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2answers
76 views

EMC - conducted emissions - unused wires in cable - puzzling coupling

I am trying to understand the impact of unconnected wires in a cable for EMC conducted emissions tests. My product has a shared unshielded cable for supply and communication (I know it's bad practice....
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0answers
28 views

Sensing of AC current. Isolation Capacitor Problems?

I want to measure the AC Current flowing through a Piezocrystal (replaced in the circuit with a resistor) being driven by a TI DRV2700. http://www.ti.com/lit/ds/symlink/drv2700.pdf This Chip puts out ...
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1answer
48 views

Unused/floating pins on BTS5016

I plan to use Infineons PROFET BTS5016 in a coming project. https://www.infineon.com/dgdl/Infineon-BTS5016-2EKA-DS-v01_00-EN.pdf?fileId=5546d4625a888733015aa41a5e161129 I will not use the ...
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3answers
168 views

About floating ground and circuit problems

Good morning, I have a power supply with floating ground that drives my circuit. Since the circuit doesn't work as expected (it works fine only if the ground is tied to earth) I did some measures with ...
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6answers
128 views

Is a floating pin equivalent to a very weak pull down?

I know that if a MCU pin is configured as "input" and it is not connected to any pull up/ pull down resistor, it is said to be floating. In this situation, we could say that the pin is in series with ...
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7answers
748 views

Why can a MCU input floating pin easily change state?

I would like a technical ("engineering") explanation of why a MCU input floating pin can easily change its state depending on the outside electromagnetic interference. Is it related to the fact that ...
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2answers
41 views

How to handle disconnected resistive sensor?

I'm trying to connect a PT100 thermo probe to an Arduino project to measure water temperature. After some research I have found and adopted a design using a Wheatstone bridge and an instrumentation ...
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2answers
238 views

Is it possible to get a floating power supply to power multiple MOSFETs

Hey guys this is my first post on stack exchange so please go easy on me! I have a hobby project where I was trying to make a few batteries go in series using a micro controller and a floating power ...
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6answers
5k views

Is a pull up/down resistor really necessary?

Logical reading (1 or 0) of a micro-controller input GPIO pin may float if it is neither connected to VCC nor GND; someone said it is because of surrounding RF interference. When a floating GPIO ...
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1answer
59 views

How can I simulate the circuit with floating node in Orcad simulation?

I simulated to test 4n25 optocoupler. 6 pin in 4n25 is base of output transistor. According to google, 6 pin can be not connect pin (NC) because input LED generate the base signal. Orcad ...
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1answer
131 views

555 Timer Output Always V+ or Ground?

If the output of the 555 timer is not trigger to high, is it ground? Or is the output left floating?
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1answer
75 views

Micron NOR unused pins have pull-ups. Any danger just leaving them there?

I have a board designed for a dual-die Micron MT25QL512 QSPI NOR flash. These parts are in short supply, but the board fabricator had some single-die MT25QL128, and used them instead. The single-die ...
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1answer
76 views

Floating Power Supplies

Referring to this post, is it possible to float power supplies by simply not connecting the ground wire?
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1answer
53 views

Constant Offset Floating Supply

What circuits can be used to provide a voltage supply capable of sinking around 1A of current that will always float 10ish volts below a given supply, that could be from 12 to 200 volts? I have ...
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1answer
67 views

Floating analog input value

To use my sensor I need to supply 24V. So I converted 4.5 V from battery pack to 24V and converted it again to 0-1.66V using a voltage divider. So far I can read the output of the sensor using the ...
2
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1answer
77 views

Measuring small currents at DC high voltages without floating meter

I'm doing a project with a Cockcroft-Walton multiplier that will output up to 40 kV DC at up to 10 mA. The the circuit takes an input of 10 kV AC at 60 mA and 60 Hz (from a neon sign transformer) and ...
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3answers
1k views

How can I float a pin that otherwise should be low?

I want to enable/disable a TI TPS54302 buck regulator with a microcontroller. The enable (EN) pin should float to enable the device, or be tied low to disable it. I currently have the EN pin ...
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8answers
5k views

What is the right way to float a home lab?

I just got myself some new toys for my lab at home like 30V DC power supply, KKmoon signal generator and a Rigol DS1052E. I want to float everything, because I don't want to spend any money on stuff ...
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2answers
1k views

Disconnecting ATX PSU's ground from mains earth to protect my oscilloscope

Like many I took an ATX PSU, hooked green to black, and have a nice PSU. I am experimenting with a HP oscilloscope from 1997 and as you know, those are grounded to main's earth, just like my ATX PSU. ...
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2answers
124 views

Consequences of leaving unused inputs of clock buffer floating. Alternative: best practice

I'm using a Si53342-B-GM Original datasheet download at silabs for the si5334x-series as a clock buffer. In some cases I only need to distribute a single clock signal and in some of my cases I ...
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3answers
278 views

Why does a pull down resistor eliminate floating input

Ever since I connected a button to an Arduino for the first time, I've wondered how does the resistor prevent floating input from happening? I've read several answers to similar questions, seen videos ...
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1answer
509 views

Floating input in Op-amp Readout Circuit?

I was analyzing this circuit diagram in a thesis about a capacitive EEG electrode. The author talks about a flaw in the design where there is a "floating analogue input" that is causing the op-amp to ...
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1answer
40 views

Isolated power supply with output on a 2kVDC floating ground

I am building a system of detectors which are referenced to independent floating grounds. The maximum voltage between each stage is 2kVDC. So I need isolated supplies which can operate continuously at ...
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1answer
172 views

Floating neutral in TN-S or TN-C-S earthing system

Since neutral is bonded to ground at building distribution point in a TN-S or TN-C-S earthing system, could floating neutral happen under the following conditions: Loss of N and/or PE at transformer ...
2
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1answer
2k views

Design for a balanced (positive and negative) HV DC regulator

I'm trying to design a high voltage DC regulator for driving a PZT that will provide both +200 and -200 V outputs referenced to ground. The input is a rectified AC waveform that will provide UK mains ...
3
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1answer
595 views

Why are the dimensions of a floating gate layer in a MOSFET so thick?

For a floating gate MOSFET, in order to make the control gate work you have to(generally speaking) make the oxide layer thin(~100 Angstroms) as well as the ONO(Oxygen nitride, acts as an insulator) ...
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5answers
18k views

Confusion about the meaning of floating

Here they define being floating as: They mention Ungrounded = Floating. But in another forum someone wrote: The signal is consider floating when it does not have the same ground with your ...