How to make an Electrostatic Polarity Detector(Electric Field Detector) 

Thomas Kim has the steady hands of a brain surgeon! He makes soldering to the teensy Mosfet look easy but it was pretty tricky for me. Since I was taking too much time and heating the chip too much, I was damaging it. It would work perfectly for a bit and then start misbehaving. LED would stay on or come on by itself. Pushing the tact switch started making one LED light up. And so on. So I bought 10 Mosfets and kept at it until I could get them soldered up quickly. This is an elegant design. Thanks to Mr. Kim for posting this.

Wow, that’s some careful, steady-hand solder work!

As always, Great video Thomas. Thanks!

Really, really nice, man. Fantastic work!

Very useful, will make a great gift for my niece.

Excellent!! Thank you.

Nice! 100% like :-). If I get around to building one it will be in a black project box. The LEDs will be placed so that they shine on the end of the straw inside the box, thus the whole straw lights red or blue, mauve for AC. The battery will be a CR3032 lithium button cell. The tactile switches will be rubber buttons from an old keyboard, so the box wont need taking apart to operate.

Very nice video Bhai. Beautiful picture.

Great idea! Thanks for sharing. I understand it is possibile to make this curcuit with any N/P enhanced channel mosfet pair. There might be difference in sensitivity, but it should wiek, right?

Nice one! I'll build one of those soon :D Thanks!

Very good!!! Congratulations from nord est italy!!,

I made this and circuit and thought it was totally awesome. I epoxied everything securely together and fried the chip with a spark from the PVC pipe I had rubbed. So I turned on my 200kv Van De Graaff generator and zapped the crap out of it until it was completely FUBAR.

_really cool_

Thanks for sharing

This seems like it could work for a secret lock or something similar. Would it be possible to expand the circuit?

Can I have a question, pls? In my country there is no FDS8958A, can I use AO4060 transistors? Thank you very much!

circuit diagram is at 7:13, took me some time to find it..

I just completed this build and it works great!!! One question I have though is how do you discharge the LED's so easily? Mine if they detect a heavy charge in either polarity they have a tendency to just stay on even when I try and discharge it with a material with opposite triboelectric polarity.

What diameter or awg is the wire for the "antenna"? Could it be made of multiple core? Are there significant differences?

Thomas Kim, ensina a como fazer um Van de graff com melhorias

Hi I tried making the circuit on breadboard using npn (bs170) and pnp (bs250) mosfets instead of the IC but it doesnt work. The leds remain off and do not respond to a pvc pipe rubbed with wool. Only a couple of times i saw one led flicker very dim. I use 3V (2 AA cells), I also replaced the npn bs170 mosfet with irfz44 mosfet and now one led keeps glowing all the time and the other led glows if press the switch. What could be the issue? Also, why are the 2 tactile switches used in this circuit if they are never pressed? Thanks.

Have you tested these out on a dielectric pulled out of a "dissectable capactor" ?

Hello, thank you, I built the same as you, but the red led never lights up. Always the blue lights up. Red works fine with 3v though. An idea ? Thank you

Cool 😎

Thank you for showing, very interesting ! So very interesting that I have just ordered me some FDS8958A :) I hope my eyesight will be good enough to solder such a little chip, I have never done SMD, only dil and other 'regular' discrete components.

i cant find the fds8958a ic..? can i use some other ic instead of this....??

Buen trabajo

Great idea and skill! But I don't understand the switches for, are they normal close?

you use nice and taft van de graaff, could you share photo components of it?

What kind of straw did you choose this is Teflon in a glass tube?

Hello, how long are that wires? Thank you

Hey Thomas Kim! I'm ramping up on some of my experiments and I was thinking about this design. Is it possible to use the same circuit but in place of an LED to put probes to a voltmeter to detect intensity of the field given proper calibration? I'll probably test it as I build my copy of this design. But thought I might share that thought with you.

can i use normal MOSFET's , what transistors are they

Could you explain or forward me to a website ( or theoretical material) how is it detecting the different polarity and reacting to it. I understand that the chip ( which I'm not too sure what it does) detects electric field but how and why does it react in a way that when a negative charge comes in one LED turns on and not the other. Does it have to do with the position you soldered the connections? Even if it's positioning, does the chip work in such a fashion that one side detects one polarity, and the other side the other polarity? If this is what happens, how does it happen? How can that microchip do that? I am familiar with maxwell's equations but have a hard time understanding eletronic devices ( specially microchips and such). Sorry if it's an obvious question, and thank you for posting.

Hi !! can you recommend me some alternative tester aside from using the van de graaff thing ?? thanks ..

How to understand this circuit? Would you recommend any path of learning in order to learn such "practical" circuits? I had some circuit theory during my studies, but we were calculating some stuff that noone even understood. I didn't learn anything from these lessons. I'd like to learn on my own. Thanks in advance!

But how did you make a van de graaf machine

Thank you for sharing nice video tutorial easy to understand FDS 8958A can replace the other one?

Hi - great circuit. May i know what is the purpose of the tact switches. Reason being that it us always off. Tnx

Hi kim little switch are needed? I try without switchs and red led always on with a small light but work when touch it. Really work whit switchs? Sorry english tnx.

Hi! This is awesome! I would love to build one. Sadly I fail to understand the use of the buttons. Are yours the type that close the circuit only when pressed continuesly? What is their purpose? Any help would be great!

how about using LED bipolar ?

can't find the chip, anywhere! Please help me out!

Thank you so much for this! I couldn't find the FDS8958A s oI'm using SI4532A. Will it work the same?

Hi Thomas. Would You sell me some of Your equipments? I am willing to buy Your electrostatic polarity meter and some other stuff too.

What is that thing you r holding

What are two things after ic

안녕하세요~ 영상 보면서 비슷하게 하나 만들어봤는데요. 저는 고휘도 led를 사용해서 저항은 제거하고 연결했습니다. 근데 led가 꺼지질 않네요. 전원넣고 가만히 놔두면 혼자서 빨간색이나 파란색으로 랜덤하게 켜집니다. 점점 밝기가 증가하구요. 그 상태에서는 정전기를 가까이해도 반응이 없구요. 초기화 해서 다시 작동하면 또 되었다가 안되었다가 도통 알 수가 없네요.

I wonder if you could detect a charge during a thunderstorm by pointing it up to the sky.

Seems to be impossible to get the FDS8958A chip, I've found one place that sells it and the estimated arrival time is 7months

What are switches used for?

..nice idea use tact switch as high voltage capacitor.

Why buttons? As an IC holder? Or as a capasitor?

Good

Plz send Chip buy link

is there any alternative chip for this circuit because I donot found your one. plzz reply. thank you

what type of bottle is it and thickness of staraws etc?

Very nice! Can I use one 3.7V rechargable battery?

Sir ,we Can't purchase this ( Fds8958a) ic in India so please tell me relevant ic for this circuit.

is there any replacement for fds8958a chip?? it is very difficult to find

Hi, I'm from Uruguay, so I can replace the chip (FDS8958A)

I tried to make this and both of my led are always on did i do something wrong?

Sir, I have tried this ckt but not working..?

I want to make this project but I'm not getting that ic...any replacement for fds8958a ic pls!??

Is that an isolation chip?

Amazing, is there any equivalent IC to FDS8958A?

Hi,thomas can we use 555 timer ic instead of this to make this circuit please reply immediately. bro.

What is the purpose of those buttons?

what is that device that is in your hand

Also can I use a 555 IC?

Why red and blue LED? They are so far apart considering forward voltage.

Schematics?

how to make positive and negative van de graaff

Circuit daygram plz🙏🙏🙏🙏🙏🙏🙏🙏🙏

What's the purpose of the buttons? If you didn't click them, then the current flow wouldn't be possible or what?

I live in the US. Those bottles are no where to be found here. Here we have plastic bottles, but none of them have nice straight walls. Thanks!

That thing is just a plastic straw? I thought it was some Wi-Fi antenna 😆

can this be done with other microchips

whats the part number on the buttons?

Send me the link of old version with 9v battery

Maybe it makes sense to add gate protection? Zener diode?

Please show atleast a circuit diagram of this.. it's difficult otherwise..

just watch and click like

Извините, не понимаю :(, зачем вы поставили кнопки?

散了吧，要小主板的

Bizarre choice of mosfet package. Why not just use two discrete mosfets with schottky body diodes in TO packages where the lead outs are wires? Those microscopic SMD devices are almost impossible to work with and virtually unsolderable without damaging the device! ??? Old is o'd... New is cool innit :) Why the hell do people just throw out the baby with the bath water on projects like these.

Circuit Drawgram send me plz

U maked 4 for sale? )))

Can I make this without a button?

that fds8958a chip isent easy to get its not even available on e bay so not many can build this circuit, the 2 electronics stores here jaycar electronics and altronics both dont have this ic chip

230v line tester

Bhai iska samaan Kahan milega

FDS8958A MOSFET : SMD soldering is not so easy : Get an MSOP - 8 female to DIP - 8 male adapter and save yourself a ton of time and nerves.

well someone down the page says he got the part from mouse electronics its mouser with a letter r on it and they dont even have it in there online catalogue, so i did some digging, and in australia where i am rs components sells this ic chip part and the minimum you can buy is ten for $11.61 but im in western australia they used to have an office here only but according to the rs components chat person they are in sydney and to make things worcer they are out of stock , and have to back order and if they coming from over seas it may take time even more if its routing through china where customs scans everything now and slows the postage down from coming out of china and to make things even more worse rs components takes bank deposits and bankcards only so if ya not working and dont have these cards ya stuffed so the typical hobbyist cant get them i told them that being out of stock is the worst thing a customer hears and that that western australia where i am this state relies to much on lenghty interstate imports cause they dont have anything here most of the products have to come from eastern states , i asked them dose my visa debit qualify as a bank card they couldn't answer that , they shuffled me onto another to answer some qestions so i left , they would do better if they stock up more and bring out better buying options than the other which cuts customers off from trying to buy from them buy making the payment options so limited .

Dinesh Kashyap

using for what?

اي الاستفادة من كدا طيب 👀👀

Hi

Very weak circuit. Mine can detect up to 12 feet away

Thanks for sharing