Questions tagged [floating]
A voltage that is not connected by any conducting path (including resistors) to ground or the key voltage reference point.
78
questions
2
votes
1answer
57 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 ...
6
votes
3answers
858 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 ...
1
vote
2answers
49 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 ...
2
votes
3answers
132 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 ...
0
votes
1answer
50 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 ...
0
votes
1answer
33 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 ...
0
votes
1answer
75 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
...
15
votes
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 ...
0
votes
2answers
102 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 ...
1
vote
1answer
51 views
Can I leave it unconnected pins in the level shifter?
My concern is that pins are connected between DB25 and TXS0108E, but are not connected between TXS0108E and the Header 5x2. There is only the tracks between TXS0108 and the Header 5x2, but there is no ...
1
vote
1answer
128 views
Floating DC power supply (solar panels) - do I need double-pole breakers and why?
I am in the process of building a small off-grid solar setup.
There will be 4 parallel strings of panels in this setup, and I understand that for 3 or more strings, you need some sort of over-current ...
0
votes
4answers
249 views
Floating Source Voltage Difference to Earth
I was reading about floating voltage on web but there is something that I couldn't understand. I attached photo of circuit. As you see it shows 60v difference between neutral of flating source and ...
0
votes
1answer
129 views
Can I leave the input pins of an ADC channel in floating state?
I'm using this 4-channel ADC: MCP3422 -> Datasheet
I only need to use 3 of the available 4 input channels in total.
Normally I would add footprints for pulldown resistors for example in case a ...
3
votes
1answer
137 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....
1
vote
1answer
157 views
Floating analog input using Arduino with 1m cable
I use an analog input from an Arduino to read the value from a piezo plugged in parallel with a 1M ohm resistor.
I followed this tutorial from Arduino: https://www.arduino.cc/en/Tutorial/Knock
Here ...
1
vote
1answer
167 views
Trying to understand floating voltage
I'm trying to understand the concept of a floated voltage, and why it is needed in some cases.
For my own case, I am using a variac connected to a rectifier to provide a DC voltage for a circuit, (...
0
votes
1answer
61 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?
1
vote
0answers
45 views
Preventing the voltage between two isolated grounds from exceeding max rating
Consider the low-side current sensing application shown in Figure 1. Grounds 1 and 2 are galvanically isolated. Assume, for example, ground 1 is the NEUTRAL line on mains power (\$V_g\$), and ground 2 ...
1
vote
2answers
371 views
Grounding a Laptop
I have the following problem: I am currently debugging an electronic sensor board which is connected to the USB port of a laptop. The USB port is used both for communication via UART and to supply ...
4
votes
2answers
646 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. ...
1
vote
2answers
53 views
Measuring floating gate potential with minimal leakage current
I am working on a sensing device where the voltage of a floating node is dependent on the quantity to be sensed, as well as the net charge stored in the node. I would like the device to be only ...
3
votes
2answers
441 views
Current source with grounded Load and floating power supply
The following circuit represents a basic op-amp current source and can be found in the "Art of electronics 3rd edition" in page 228.
\$ I_{load} \$ is easy to calculate in this situation.
The ...
0
votes
2answers
69 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 ...
0
votes
1answer
329 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.
...
0
votes
1answer
65 views
Can I use a source follower to read the floating gate voltage then add a fixed tunneling voltage, then feed it back to the tunneling electrode?
So I was reading this research paper:
H. Kosaka, T. Shibata, H. Ishii, and T. Ohmi, “An excellent weightupdating-linearity
synapse memory cell for self-leaming neuron MOS
neural networks,” in IEDM ...
0
votes
1answer
104 views
Flyback smps or floating buck converter?
I want to drive a 180V/1A string leds from 220VAC.
Which topology should I use:
flyback smps (with transformer) or,
floating buck step down converter?
I know that buck converter will be not ...
0
votes
3answers
69 views
ATmega328p TQFP and unconnected pins, what is it the best practice?
I'm designing a board based on ATmega328p in TQFP package.
I'm not using all the ports, so, for example, ports from PC0->PC5, ADC6 and ADC7 won't be connected to anything.
Can I left them unconnected ...
0
votes
1answer
129 views
Oscilloscope differential measurement for battery powered circuit using single probe
I want to measure the voltage across a resistor in my circuit. The circuit is battery powered. I don't want to use the two probe method and calculate A-B to get the results. Can I use one probe to ...
0
votes
1answer
75 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 ...
0
votes
2answers
328 views
floating ground
For a big machine (rope shovel) we put a custom electronics board (gps) in an enclosure. It is connected to the cabinet with Power over ethernet (POE). The POE switch is connected to an isolated power ...
2
votes
1answer
172 views
Confusion with calculating the mantissa of a floating point from a binary number
I use this converter to convert a 32-bit binary number to a floating point number. I first find the hexadecimal of the 32-bit binary number and convert to decimal by using the converter.
In my case ...
0
votes
0answers
75 views
Voltage regulator outputs some voltage even if in shutdown
I've created a dual source energy harvesting board to store energy from small energy sources, like a 3V 15mA solar panel, into a 3F 2.7V supercap and to power a small wireless node (3.3V, 30mA), but I ...
2
votes
3answers
737 views
Understanding Common Floating Return [duplicate]
So I'm pretty new to electronics, and I'm getting slightly hung up on the concept of ground. I'm thinking the circuit diagrams below will help me to explain this frustration, because there's not an ...
1
vote
2answers
551 views
Getting shocked because of floating ground on psu [closed]
Angus from makersmuse explains here how he got shocked from a printer with floating ground.
https://youtu.be/v1OuYg7AJjw
I don't really understand his explanation.
He basically says that if you ...
11
votes
5answers
12k 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 ...
2
votes
2answers
579 views
How can I return an Arduino digital pin to floating state?
I am trying to setup a programmed reset function for a 3.3V BlueTooth module that resets when its reset pin is pulsed LOW for a short period of time. There is a 47K pull-up resistor in the BT module ...
6
votes
1answer
766 views
why trace_printf(“%f”,x); triggers a HARD FAULT on a stm32 MCU?
I'm using a stm32 F413ZH microncontroller with HAL libraries (mainly written to be used with c but can also be used with c++) in eclipse, actually I managed to completely configure eclipse including ...
0
votes
0answers
295 views
Can I leave bootstrap pins floating? (Internal pull-up)
I have a microcontroller that uses 4 GPIO pins as "bootstrap pins". The state of these pins (high/low) at boot time will determine important features of the microcontroller, such as output voltage to ...
1
vote
1answer
196 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 ...
0
votes
1answer
214 views
Floating supply voltage
I'm building a device to, among other things, measure a few voltages from different power supplies that are expected to be floating. Because the user might do silly things like connecting them in ...
1
vote
0answers
618 views
Potential difference between DC floating power supply and earth ground
I have a question about a simple DC floating power supply: it is as simple as possible, secondary coil -> bridge rectifier -> filter cap, as shown on the figure below.
If I connect the input of the ...
2
votes
2answers
1k views
Star point in schematics
I read somewhere that in a mixed signal ckt , the analog part and the digital part are supposed to be better when they have different power rails and ground lines , but to avoid floating of the ground ...
6
votes
7answers
2k views
Getting two (or, one and a half) outputs from a single pin
I am doing a project with an ATtiny85 and of course I'm short on I/O pins. One idea I had was to use a single pin for two outputs (let's call them EN and DATA).
simulate this circuit – ...
0
votes
1answer
159 views
Altium 17: Multichannel Design “contains floating input pins”
I get
Net SCL/SCK contains floating input pins (Pin U1.1-4,Pin U1.2-4)
as the only error after compiling the project but I don't know why.
The clock signal as well as V+ is shared among the ...
0
votes
1answer
131 views
Function Generator - Signal without Neg or Gnd reference
I have a new PC based function generator (very cheap), and an old BK Precision function generator. The old BK Precision can output a signal without the ground or negative reference lead from the BNC ...
1
vote
2answers
249 views
Is it bad to leave a filter capacitor floating?
The circuit detail presented is a gyrator filter that is one of two that hang out in the feedback loop of an opamp, creating a "low" and "high" tone control for audio. (The "low" section is shown) I'd ...
0
votes
3answers
378 views
Can a 1:1 transformer prevent the SMPS noise of one load from reaching other loads plugged into a mains outlet?
It's my understanding that a load which has a SMPS can put noise back onto the power cord, which could reach another component that's plugged into the same outlet.
Is it true that a 1:1 transformer ...
0
votes
0answers
412 views
Who do IGBT rectifiers have floating gates (unlike MOSFET rectifiers)?
When I search Google Images for "IGBT rectifier", I notice that they all appear to have floating gates.
But don't IGBT's have gates like the ones on MOSFET's, in which it's insulated from the other ...
0
votes
2answers
869 views
How to check if pin is floating or connected to ground?
I am using a DC jack which has 3 pins. 2 for power and one pin which is connected to ground when there is nothing plugged into the jack and disconnected from the ground when the jack is plugged in.
...
0
votes
2answers
92 views
Do I need PSUs with similar current rating when I connect them in series?
I need a 48V power supply with 20-25A so I decided to use old ATX power supplies I have lying around.
I know already that the series of ATX PSU can be used to charge lithium packs for RC planes, it ...
