Can I bias the arduino uno ground pin with a high voltage?

Hello, I want to use the arduino uno to generate a pulse (just a simple blinking code) as the TTL to control the gate of a MOSFET.
The problem is the source of the MOSFET is not true ground and is biased with a high voltage (100 V relative to earth).
So, I'm wondering if I can bias the ground pin of my arduino to 100 V, so that the output pulse voltage will be 105 V? Will it fry my arduino?
Thanks!

No need to move the ground of Arduino.
Use an optocoupler and you can easily solve this problem.

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To answer your question..... depends. The key here is what else is connected to the Arduino inputs etc and how is the Arduino powered.

The other question is one of safety. My guess is because you need to ask the question you should not be approaching in such a way.

While an opto isolator can make is safer it cannot supply any gate voltage to the mosfet so you would need another supply to control the mosfet gate.

you could:

  1. use a 9V battery for mosfet gate power and an optoisolator.
  2. use a pulse transformer directly to the mosfet gate. maybe something like pulse transformer

You might find this app note useful A Guide to Gate Drive Transformers

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That can "work" but it's generally a very bad idea.

Of course the Arduino's power supply (and anything else connected to the Arduino) has to be floating (relative to earth ground) and then if you touch the 100V "ground" you could be shocked, or if you plug-in the USB to your computer your computer's ground will have 100V on it, or if the computer is earth-grounded you could fry your computer, etc.

P.S.
In most jurisdictions anything greater than 48V is considered "dangerous" and must be insulated & isolated so nobody can touch it. But of course, 48V is enough to fry your computer's USB port or other low-voltage electronics.

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what is the whole aplication?

Why does the MOS-FET-source have to be at 100V?
You can buy a lot of different MOS-FETs N-channel or P-Channel.
N-Channel/P-Channel-MOS-FETs are connected in a different way.

SO you should give an overview about your whole project. With a circuit. Very often it is possible to find a different solution that works better or is easier to build.

best regards Stefan

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Thanks and I did some search. It seems optocoupler and mosfet will do very similar job, except optocoupler doesn't the Vgs threshold voltage like mosfet?
If my understanding above is right, then I can just replace the mosfet with an appropraite optocoupler to make it work?

Thanks

Thank you! Assume no pin on the arduino is connected to anything, I powered my arduino with a 9 V adapter connected to the 110 V AC from the wall, if I apply 500 V to the GND pin of arduino, will I destroy the electricity of the whole building? Please bear with my layman questions.
Thanks!

No.

Before I answer further, where is the 500V coming from?

Given the 500V is from some power supply, you will likely destroy the 9V adapter and possibly your Arduino.

Most of the folks here assume when a MosFet is being used there is power being controlled, not just a low power logic signal.
Opto Isolators are typically not designed for their outputs to switch power. So the questions is..... what are you trying to switch with you MosFet?

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If you barely know almost nothing about electricity you should stay miles away from real experimenting with high voltages !!
If this are just thought-experiments it is OK to learn.

Destroying a whole building depends on the current. Not so much on the voltage.
If you slurp across a plastic-carpet in plastic shoes while the air has a low humidity
you can charge up your body to several thousand volts.
As soon as you touch doorknob the charge will discharge through a spark from your finger
which is a bit uncomfortable but undangerous because the current is so low and the time the current flows is so short.

Anyway this small discharge is way enough to destroy any MOS-FET!
Even if you don't feel the spark electrostatic discharge can destroy a MOSFET

In the situation: your arduino is supplied by a wall-plug that transforms 110V down to 9V and now you connect your Arduino-GND with 500V if this is causing any damage depends on the inner circuitry of your wall-plug and it depends on is your 500V isolated against anything else?

Again: I'm asking what are you planning to do? Do you want to keep it a secret because it is illegal?

You can have the experience for a lot of money by destroying multiple Arduinos though the magic smoke will not explain what really happend.

But you will be way better if you describe in detail what you are trying to achieve in the end.
best regards Stefan

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if you barely know anything about electronics you should ask a lot of questions before starting the real project. Optocouplers can switch current between 0,01A and 0,05A. MOS-FETS can switch currents up to 200A! or even more. Which MOS-FET is suitable for your still kept undercover project depends on the voltage, the current and on the Gate-threshold-voltage

So again: give a detailed description of what you plan to do!

best regards Stefan

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I guess what we are trying to say is, we are worried about you and folks who may be using some of the discussed equipment may literally die.

This is not an exaggeration, many of us have heard of deaths buy exposure to high voltage. You might think of these high voltages as you might if you had a dozen or so components that were covered with a nerve agent that would kill you instantly. What your talking about is very similar.

So I hope you stay safe.

My final statement on leaving this thread is....... in the immortal words of Buford T Justice " you can think about it ... but don't do it"

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Hi,
Is the MOSFET you want to pulse N-CH or P-CH?
A basic diagram of the power and load circuit around the MOSFET would help.

What is the application, what is the device you are pulsing and why?

Tom... :smiley: :+1: :coffee: :australia:

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So we have a blatant "XY problem" here. :roll_eyes:

Useless to discuss until we can start from the beginning.

What on earth are you actually attempting to do? :astonished:

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Hi,

Do not do this, you will be placing the components inside the 9V adapter at 500V above gnd.
Most plug packs have no electrical standards testing.
They may not be able to withstand the 500V potential difference.

WHAT IS YOUR APPLICATION?
WHAT IS AT 500V ABOVE GROUND POTENTIAL
Can you please tell us your electronics, programming, arduino, hardware experience?

Tom... :smiley: :+1: :coffee: :australia:
PS I would strongly suggest until we have at least the basic information of your project, that we cease and desist giving you more construction information.

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Seems we are all saying that, one way or another ... :roll_eyes:

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Thanks a lot for your kind reply! I won't try it in real myself because I know I shouldn't. It is just some thought for now and if I'm going to do it, I will ask an expert but right now the expert is not vailable.
For the application, I uploaded the diagram of the circuit below. In brief, A and B points are connected to two sets of wires. When the MOSFET is off, the voltage difference between A and B is high, and it becomes low when the MOSFET is turned on. This will be used as an ion shutter to block ions (when MOSFET is off, the voltage between the two wires will deflect the ions) in this project. Now I got it is a bad idea to connect the MOSFET source to arduino, is there any alternatives to achieve the idea? Is there any electroinc component that can be used as a switch like MOSFET but doesn't need a certain Vgs threshold to turn on?

Thanks!

Best Regards,
dz4399

Thanks! I attached the diagram on #16. I'm happy to provide any further descriptions if I that description of the circuit is not clear.

You haven't specified how high the voltage is.

The MOS-FET has to be specified with a voltage that is even higher as the highest voltage that can occur in your device.

Here is a 4500V high voltage MOS-FET.
<https://www.mouser.de/new/ixys/ixys-4500vmosfet-mosfet/
At this voltage-level
the signal to switch on/off the MOSFET should be electrically isolated by a highest voltage optocopupler.

So next step is to really specify the highest possible voltage than can occur.
If you don't know it my recommendation is to do research on ionic thrust.

I remember that I have seen a video where a model plane that was driven by ionic thrust was tested.

Anyway it brings me back to that you should give an overview about the final purpose of your device. creating / blocking ions is not a self-purpose.
What is the final final final effect you want to achieve?
Very often there exist multiple ways to achive the final thing.

So what is it?
best regards Stefan

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I think the curcuit is not as dangerous as it seems at the first glance when we look at the 500V. There is a resistor with 1 Megohm, which reduces the maximum current to 0.5 mA. A short search on the internet shows that a current of 1 mA ist not dangerous, it is just the threshhold of sensation. Electrical Safety: The Fatal Current (ohio-state.edu)

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Hi Stefan,
Thanks a lot for your advice and patience. Sorry I should've mentioned that in the beginning but I didn't since I thought it was kind of irrelavent.
So, what I want to do is to pulse an ion shutter (Bradbury-Nielsen Gate) for an ion mobility spectrometer. A schematic of an ion mobility spectrometer: Working-principle-of-an-Ion-Mobility-Spectrometer_W640
The ion shutter is like the picture attached (copyed from this paper: C. Chen, M. Tabrizchi and H. Li, Ion gating in ion mobility spectrometry: Principles and advances, Trends in Analytical Chemistry 133 (2020) 116100): ion gate
The ion gate controls weither the ions can enter the drift tube of the ion mobility spectrometer. The high voltage is necessary to maintain enough electrical field of the drift tube. The 500 V in my descrpition above is actually very low compared to the typical voltage. The voltage of the ion gate relative to ground depends on the design of the instrument but typical voltage of the ion gate can be 4 kV relative to ground. As the figure shows, 100 V voltage difference between S1 and S2 is need in order to effectively deflect ions (closed state), for exampe, S1=4 kV, S2=3.9 kV is the closed state, S1= S2=3.95 kV is the open state.
ion gate2
waveform2
Hope this makes it clearer. Thanks and I'm open to any suggestions.

Best Regards,
dz4399