where's your rld connection ?
https://en.m.wikipedia.org/wiki/Driven_right_leg_circuit

I've just seen your post with a wrist strap going into a tank of water in a plastic tank, on a concrete Base.!

what are you hoping that this does ?
it reminds me of a water based leaden jar !

what is your aim with this circuit?

 

where's your rld connection ?
https://en.m.wikipedia.org/wiki/Driven_right_leg_circuit

The unit doesn't use RLD. Only virtual ground.

I've just seen your post with a wrist strap going into a tank of water in a plastic tank, on a concrete Base.!

what are you hoping that this does ?
it reminds me of a water based leaden jar !

what is your aim with this circuit?

The aim is to prevent static damage to the inputs of the amplifier. It is in the unit manual. I'll post the last pages of it for continuity and context:










I don't have earth bonding point inside the house. So I connected it to the water tank outside standing on concrete which is connected to the earth and connected to the grounding rode of the power pole that is connected to the neutral of the transformer.

This would sink any static into the water tank and earth, isn't it? Why not if it won't??

 

The unit doesn't use RLD. Only virtual ground.



The aim is to prevent static damage to the inputs of the amplifier. It is in the unit manual. I'll post the last pages of it for continuity and context:

View attachment 354068


View attachment 354069


View attachment 354070


I don't have earth bonding point inside the house. So I connected it to the water tank outside standing on concrete which is connected to the earth and connected to the grounding rode of the power pole that is connected to the neutral of the transformer.

This would sink any static into the water tank and earth, isn't it? Why not if it won't??

Esd.
What's the electrical route from the water to the earth ? Waters in a plastic insulating tank ?
Concrete is also a insulator ..

You still haven't answered what you want to do with this circuit , you say not medical or research , but what is it ?

 

Esd.
What's the electrical route from the water to the earth ? Waters in a plastic insulating tank ?
Concrete is also a insulator ..

You still haven't answered what you want to do with this circuit , you say not medical or research , but what is it ?

It's a steel tank. When I measured one of the hot wires inside my home and one multimeter lead to the steel tank, it measures 115V. The voltage inside the house is 230V. What is the resistance of concrete? So the hot wire from the powerline goes to my multimeter and into the metal tank, concrete, earth, pole ground, pole transformer. It won't trip breaker because the neutral is not given to us. This is to avoid confusion especially since our electricians are all from poor sector of society who mostly are hungry from not earning regular $8 earning a day. It will only trip breaker if there is neutral to the panel where the ground is bonded with ground rod into the earth (also to lower potential in house).

Anyway. If there is short of hot wire to concrete somewhere (like in my neighbors). I guess there will be continuous fault current that won't trip. If I use antistatic wrist band,the fault current can reach it, but with 10Megaohm resistor, I guess the voltage would be down to very low level not enough to hurt me or the circuit. This was a subject of a thread about continuous fault current running under earth.

Continous Fault Current passing through Earth ground | Page 2 | All About Circuits

If there is continuous fault current running in the earth reaching the pole ground and into neutral completing circuit. There is loss of electricity and higher bill, right? My concern is if this would contribute to more capacitive coupling.

I'm just learning about measuring biopotentials for my interests in BCI (Brain Computer Interface).

 

It's a steel tank. When I measured one of the hot wires inside my home and one multimeter lead to the steel tank, it measures 115V. The voltage inside the house is 230V. What is the resistance of concrete? So the hot wire from the powerline goes to my multimeter and into the metal tank, concrete, earth, pole ground, pole transformer. It won't trip breaker because the neutral is not given to us. This is to avoid confusion especially since our electricians are all from poor sector of society who mostly are hungry from not earning regular $8 earning a day. It will only trip breaker if there is neutral to the panel where the ground is bonded with ground rod into the earth (also to lower potential in house).

Anyway. If there is short of hot wire to concrete somewhere (like in my neighbors). I guess there will be continuous fault current that won't trip. If I use antistatic wrist band,the fault current can reach it, but with 10Megaohm resistor, I guess the voltage would be down to very low level not enough to hurt me or the circuit. This was a subject of a thread about continuous fault current running under earth.

Continous Fault Current passing through Earth ground | Page 2 | All About Circuits

If there is continuous fault current running in the earth reaching the pole ground and into neutral completing circuit. There is loss of electricity and higher bill, right? My concern is if this would contribute to more capacitive coupling.

I'm just learning about measuring biopotentials for my interests in BCI (Brain Computer Interface).

its off topic, so I'll be brief.

anti static is different to earthing to mains earth.
think of if your in a spaceship floating , you still have antistatic precautions. static is about not having a voltage difference between two places.

 

its off topic, so I'll be brief.

anti static is different to earthing to mains earth.
think of if your in a spaceship floating , you still have antistatic precautions. static is about not having a voltage difference between two places.

Is it not the purpose of anti static wrist band is so the static in your body can discharge. Where else to discharge it but the most competent material, earth..

It just so happens the power companies connect the neutral to the earth creating a big conductive path. Without connecting to earth, where do you connect the antistatic wrist band? In spaceship, how do they make zero reference to their power system? By tapping the spaceship floor? (but the area is litttle only)

To be on topic. You mentioned your ac adaptor is floating and not connecting to ground. You mean it is connected to the 2 main hot lines only? Then how do you create ground reference, pls share some illustration. The g.USBamp ac adaptor may have ground connected but I think it's all isolated inside as in the following schematic shows. But if it is isolated, I wonder why failing to connect the ground at primary can produce horrible harmonics.

 

Is it not the purpose of anti static wrist band is so the static in your body can discharge. Where else to discharge it but the most competent material, earth..

It just so happens the power companies connect the neutral to the earth creating a big conductive path. Without connecting to earth, where do you connect the antistatic wrist band? In spaceship, how do they make zero reference to their power system? By tapping the spaceship floor? (but the area is litttle only)

To be on topic. You mentioned your ac adaptor is floating and not connecting to ground. You mean it is connected to the 2 main hot lines only? Then how do you create ground reference, pls share some illustration. The g.USBamp ac adaptor may have ground connected but I think it's all isolated inside as in the following schematic shows. But if it is isolated, I wonder why failing to connect the ground at primary can produce horrible harmonics.

View attachment 354089

no. Esd is not about earthing , it's about common potential , so no current can flow..
Abs nothing to do with connecting something to dirt ,

 

no. Esd is not about earthing , it's about common potential , so no current can flow..
Abs nothing to do with connecting something to dirt ,

So where should I connect the antistatic wrist band? Everytime I used the EEG. I have to connect the wrist band to the long wire to the tank and haul it around the room while carrying the EEG unit from my cabinet to table and back to cabinet after done.

 

So where should I connect the antistatic wrist band? Everytime I used the EEG. I have to connect the wrist band to the long wire to the tank and haul it around the room while carrying the EEG unit from my cabinet to table and back to cabinet after done.

I think you've got the point .
You need to ensure that all parts are at a common potential
If you were in a space ship , you would not be halling a water tank

 

I think you've got the point .
You need to ensure that all parts are at a common potential
If you were in a space ship , you would not be halling a water tank

My concern is when walking around the room, my body can pick up so much static. How else to dissipate it than touching the earth via concrete and water tank. Unless one can discharge it by holding this aluminum pan while walking in the room?




Anyway. I've been thinking about this today. If the lights in a room are at 240V and the ceiling is 2.4m then the electric field is around 100V/m (simplification to demonstrate the idea). A typical Instrumentation Amplifier has a very high input impedance. If this 100V/m field impose itself on the person. How can it end up on the Instrumentation Amplifier inputs where it can possibly exceed the input common mode range of the Instrumentation Amplifier and get garbage waveforms?

I mean, does the electric field in your body induce current in the leads/wires and where the impedance is high can result in high voltage at the input of the Instrumentation amplifer (something an active electrode is made to avoid)? Or does the electric field in the body induce voltage by capacitive coupling on the leads independent or in addition to the capacitive coupling interference current (in room) induced in the wire?

 

My concern is when walking around the room, my body can pick up so much static. How else to dissipate it than touching the earth via concrete and water tank. Unless one can discharge it by holding this aluminum pan while walking in the room?

View attachment 354092


Anyway. I've been thinking about this today. If the lights in a room are at 240V and the ceiling is 2.4m then the electric field is around 100V/m (simplification to demonstrate the idea). A typical Instrumentation Amplifier has a very high input impedance. If this 100V/m field impose itself on the person. How can it end up on the Instrumentation Amplifier inputs where it can possibly exceed the input common mode range of the Instrumentation Amplifier and get garbage waveforms?

I mean, does the electric field in your body induce current in the leads/wires and where the impedance is high can result in high voltage at the input of the Instrumentation amplifer (something an active electrode is made to avoid)? Or does the electric field in the body induce voltage by capacitive coupling on the leads independent or in addition to the capacitive coupling interference current (in room) induced in the wire?

Ok.
What are you implying by the aluminium pan "joke" ..
If you want free help , that's not the way to go about it ..
The art of low noise is not connecting to water , but if equal potential. .
Good luck with this. I've tried and evidently failed ..

 

Ok.
What are you implying by the aluminium pan "joke" ..
If you want free help , that's not the way to go about it ..
The art of low noise is not connecting to water , but if equal potential. .
Good luck with this. I've tried and evidently failed ..

what "joke" are you talking about? The water tank is empty. I was just asking if one doesn't need to tap the water tank metal to earth to dissipate the static.. whether one can just hold aluminum pan to dissipate the statics built up in my body. If others know. Kindly answer. Equal potential means one has to dissipate the charge in my body as I walk on the floor or carpet for example. And when the static is dissipated, then the EEG unit and my body is equal potential.

 

I bought the aluminum pan above 2 months ago to clean my motherboard with 99% isoprophyl alcohol. So I have it lying around. I showed it to ask if one can dissipate via it the statics collected by walking on the floor without needing to put wiring to the earth outside. Anyway. To close this thread. Guys Just tell me how to estimate or compute how big should be the metal so I can dissipate the static charge. Some say to touch the computer case. This aluminum pan has surface area not far form computer casing. Is there some formula to calculate the surface area? That way I don't have to connect long wires to the earth outside. Thanks.

 

Hi Secan,
By just touching the pan will transfer some of the static charge on your body to the pan, the overall charge on the pan and you will be the same,
The static needs to discharge between you and EARTH ground, your incoming cold water metal pipe should be at EARTH potential, use the pipe.

Shuffling feet on a cloth or woolly carpet will create static on your body.

E

 

Hi Secan,
By just touching the pan will transfer some of the static charge on your body to the pan, the overall charge on the pan and you will be the same,
The static needs to discharge between you and EARTH ground, your incoming cold water metal pipe should be at EARTH potential, use the pipe.

Shuffling feet on a cloth or woolly carpet will create static on your body.

E

Why isn't the metal tank (at 2nd floor) outside at earth potential? It is empty as it is no longer in use. But it is connected to concrete and the earth. Why is the cold water metal pipe at more earth potential than the tank? Here is the water pipe in my restroom:







It's much easier to tap into the empty water tank outside, one can just put the wire in the top cover. Btw.. if you will measure the hot wire via multimeter and either the metal tank or water pipe, it is 115V so the entire house is pathway to the transformer neutral.

 

Hi Secan.
If you already know that you have a known Earthed system, what is the problem with just using that on your project?

If you have a 2 wire mains supply and one of the wires is grounded at the alternator source, you could use a suitably rated, one to one main's isolation transformer in order to get a mains ground free supply.

E

 

Hi Secan.
If you already know that you have a known Earthed system, what is the problem with just using that on your project?

If you have a 2 wire mains supply and one of the wires is grounded at the alternator source, you could use a suitably rated, one to one main's isolation transformer in order to get a mains ground free supply.

E

My house has 100% GFCI breakers in the main panel. Whenever it rains, some trip because the rain seeps into the hollow blocks and cracked concrete and got in contact with live.

What if I don't have GFCI and there is continuous fault current running in the earth. Do you consider the earth as having zero potential or not? Many homes have this short to concrete and they don't know it. Now if my neighbor has such short to concrete and the current is passing by under my metal water tank, my GFCI won't trip. So do you still consider as earth under the water tank as having earth potential?

Or to rephrase it short. If you have hot line short to earth which doesn't trip the breaker, is the earth still considered as having earth potential??

About this passage " If you have a 2 wire mains supply and one of the wires is grounded at the alternator source, you could use a suitably rated, one to one main's isolation transformer in order to get a mains ground free supply. " Please give some reference or illustration as I can't imagine what you mean.

 

hi Secan,
Read through this linked info.
As an example, Mains isolation transformers are often used in electrical repair shops to protect the repair technicians
E
https://www.powerinspired.com/isolation-transformer-need-know/

 

My house has 100% GFCI breakers in the main panel.

That implies you do have a mains ground. GFCI = Ground Fault Current Interrupter.

 

I bought the aluminum pan above 2 months ago to clean my motherboard with 99% isoprophyl alcohol. So I have it lying around. I showed it to ask if one can dissipate via it the statics collected by walking on the floor without needing to put wiring to the earth outside. Anyway. To close this thread. Guys Just tell me how to estimate or compute how big should be the metal so I can dissipate the static charge. Some say to touch the computer case. This aluminum pan has surface area not far form computer casing. Is there some formula to calculate the surface area? That way I don't have to connect long wires to the earth outside. Thanks.

your missing the point

its current flow that is the problem your trying to sort both in esd and your pick-up problem you started with.

thought experiment.,

make your pan 6 by 6 meters,
every thing you have is inside that pan,
everything is connected electrical to that pan,
no mains coming in, all battery powered .
make pan totaly insulated from the room, no wet wire needed.

what voltage will. there be between any two points ?
what current would flow ?