Shielding guitar pickups, questions...

[antigua]

My understanding to date has been that humbucking blocks alternating magnetic field noise, where as conductive shielding blocks noise that arrives in a capacitive manner, an alternating electric charge that causes unwanted voltage interaction with the pickup. But my understanding of this is still somewhat loose. So I tried asking ChatGPT version 4, to see what sort of answer it would give, and this is what it spit out:



what is the difference between the type of noise that is blocked by humbucking versus the type that is blocked by conductive shielding?



ChatGPT

Humbucking pickups and conductive shielding are both used to reduce noise interference in electric guitars and other instruments, but they target different types of noise.

Humbucking pickups:
Humbucking pickups are designed to eliminate or "buck" hum caused by electromagnetic interference (EMI), specifically the 50/60 Hz hum that comes from power lines, transformers, and other electrical sources. This type of noise is also called "single-coil hum," as it mainly affects single-coil pickups. Humbuckers use two coils with opposite polarity and wound in opposite directions. The hum picked up by each coil is out of phase with the other, so when the signals from both coils are combined, the hum is canceled out, while the desired guitar signal is preserved.

Conductive shielding:
Conductive shielding is used to protect against radio frequency interference (RFI) and other high-frequency electromagnetic noise. This type of noise can come from various sources, such as radio stations, Wi-Fi routers, cell phones, and fluorescent lights. Conductive shielding involves enclosing the electronic components, such as the pickups, control cavities, and output jack, in a conductive material like copper or aluminum foil. The shielding creates a Faraday cage that prevents high-frequency noise from entering the electronic components, thus reducing interference.

In summary, humbucking pickups are designed to eliminate low-frequency electromagnetic interference (EMI), specifically the 50/60 Hz hum, while conductive shielding is used to protect against high-frequency radio frequency interference (RFI) and other electromagnetic noise sources. Both techniques can be used together for comprehensive noise reduction in electric guitars and other instruments.



I've seen ChatGPT be wrong about all sorts of things, so I'm not implying what it's saying here must be correct, but it seems to basically be saying that the conductive shielding differs from humbucking in that it target high frequencies. It seems that humbucking works a lot better than shielding in the electric guitar context, is this simply because humbucking is more effective in the audio range, while conductive shielding is more effective in the high frequency range? The capacitance across the guitar's circuit is obviously high enough that audible sound is rolled off, let's say around 3kHz to 4kHz, isn't that filtering action grounding out high frequency noise, even if the shielding is omitted, or fails to block the noise?

[stevewf]

While experimenting for different tones, I've had the guts of working guitars laid out on the table. I've enclosed the guts in a Faraday cage, and compared the noise when the cage is grounded versus when it's ungrounded, and I can definitely hear a difference. I don't have any absolute measurements, but toiling for long periods with the guitar's innards on the table, grounding the cage and reducing the noise makes life a little more bearable.

The only refinements I can offer on my observations:
-the noises reduced by shielding seem higher in frequency when compared to the noise that's reduced by humbucking
-the amount of reduction by shielding seems less than the amount of reduction by humbucking

[antigua]

May 2, 2023 20:13:15 GMT -5 stevewf said:

While experimenting for different tones, I've had the guts of working guitars laid out on the table. I've enclosed the guts in a Faraday cage, and compared the noise when the cage is grounded versus when it's ungrounded, and I can definitely hear a difference. I don't have any absolute measurements, but toiling for long periods with the guitar's innards on the table, grounding the cage and reducing the noise makes life a little more bearable.

The only refinements I can offer on my observations:
-the noises reduced by shielding seem higher in frequency when compared to the noise that's reduced by humbucking
-the amount of reduction by shielding seems less than the amount of reduction by humbucking

That's good to know, although I've had unexpected things happen when the wiring was external to the guitar, when there's more distance between the components. I know that when I test my wiring changes with alligator clips for example, it seems much noisier than when it's all soldered down and closed up, even when the guitar in question has no shielding. 

[stevewf]

May 2, 2023 22:14:11 GMT -5 antigua said:

That's good to know, although I've had unexpected things happen when the wiring was external to the guitar, when there's more distance between the components. I know that when I test my wiring changes with alligator clips for example, it seems much noisier than when it's all soldered down and closed up, even when the guitar in question has no shielding. 

Yes, I'll second that in my experience. Getting the wiring down to size and inside the guitar has been quieter than long lines outside of the guitar. Unshielded guitar = quieter than unshielded guts, and shielded guitar = quieter than shielded guts. I don't remember comparing unshielded guitar versus shielded guts, though.

[aquin43]

May 2, 2023 19:37:55 GMT -5 antigua said:

My understanding to date has been that humbucking blocks alternating magnetic field noise, where as conductive shielding blocks noise that arrives in a capacitive manner, an alternating electric charge that causes unwanted voltage interaction with the pickup. But my understanding of this is still somewhat loose. So I tried asking ChatGPT version 4, to see what sort of answer it would give, and this is what it spit out:



what is the difference between the type of noise that is blocked by humbucking versus the type that is blocked by conductive shielding?



ChatGPT

Humbucking pickups and conductive shielding are both used to reduce noise interference in electric guitars and other instruments, but they target different types of noise.

Humbucking pickups:
Humbucking pickups are designed to eliminate or "buck" hum caused by electromagnetic interference (EMI), specifically the 50/60 Hz hum that comes from power lines, transformers, and other electrical sources. This type of noise is also called "single-coil hum," as it mainly affects single-coil pickups. Humbuckers use two coils with opposite polarity and wound in opposite directions. The hum picked up by each coil is out of phase with the other, so when the signals from both coils are combined, the hum is canceled out, while the desired guitar signal is preserved.

Conductive shielding:
Conductive shielding is used to protect against radio frequency interference (RFI) and other high-frequency electromagnetic noise. This type of noise can come from various sources, such as radio stations, Wi-Fi routers, cell phones, and fluorescent lights. Conductive shielding involves enclosing the electronic components, such as the pickups, control cavities, and output jack, in a conductive material like copper or aluminum foil. The shielding creates a Faraday cage that prevents high-frequency noise from entering the electronic components, thus reducing interference.

In summary, humbucking pickups are designed to eliminate low-frequency electromagnetic interference (EMI), specifically the 50/60 Hz hum, while conductive shielding is used to protect against high-frequency radio frequency interference (RFI) and other electromagnetic noise sources. Both techniques can be used together for comprehensive noise reduction in electric guitars and other instruments.



I've seen ChatGPT be wrong about all sorts of things, so I'm not implying what it's saying here must be correct, but it seems to basically be saying that the conductive shielding differs from humbucking in that it target high frequencies. It seems that humbucking works a lot better than shielding in the electric guitar context, is this simply because humbucking is more effective in the audio range, while conductive shielding is more effective in the high frequency range? The capacitance across the guitar's circuit is obviously high enough that audible sound is rolled off, let's say around 3kHz to 4kHz, isn't that filtering action grounding out high frequency noise, even if the shielding is omitted, or fails to block the noise?

Of course you are right and ChatGPT is wrong here which is a pity because its database probably does contain the correct information about shielding but most of the associations between guitar pickups and interference that it was trained with from the internet contain the spurious RFI tag. Garbage in -> garbage out.

The truth of the matter, as we have all experienced at some time or other, is that there are large electric fields at low frequencies - 50 or 60 Hz and its harmonics - that fill our living spaces and that conductive shielding can prevent them from reaching the pickup and pot terminals.

True RF interference is not a real problem since it has no effect until it enters the amplifier 

and it does not affect most amplifiers until the level is very high, such as from a mobile phone.

[gckelloch]

The material also makes some difference. Cu blocks more high harmonics than Al at the same thickness, but Al blocks poorly shielded rheostat noise affecting SC pickups. I just use Al tape under pickups, pickguards and in control cavities, but Cu tape might be better in control cavities. Both would be best in SC pickup cavities, but still won't reduce EMI harmonics very much. Neither will reduce 50/60Hz unless very thick. FI, Al will virtually eliminate it at 1/4" thick, but will reduce pickup output a bit as well. If you have one of those old thick Al pie tins, you'll notice a big difference just placing it behind a SC pickup.

Here's the result of a test I did with a 0.08" thick pie tin over a P90 sitting on my desk:
drive.google.com/drive/folders/0Bx0CnqsQz_uYblRTLTQwam5FS2s?resourcekey=0-HmA9RFQMWz4AYmvFTPpD2Q&usp=share_link

The noise was very strong because the leads were just connected to a cable via clips. Notice the reduction in the critical hearing range where it matters most. Cu might be even better. You could try cutting and stacking thin Cu discs under a pickup. I bought such discs on Etsy pretty cheap for a decorative counterweight I made for my baritone.

[aquin43]

When creating a cavity shielded against electrostatic interference, the type of material has virtually no effect as long as it is reasonably conductive.

A single plate of conductive material will shield against an alternating magnetic field to some degree by creating a magnetic shadow on the side facing away from the source, since voltages induced in the plate will create circulating currents that oppose the magnetic field. Such a shield would be very impractical and too directional to be of much use. A full shield of this type - intended to stop magnetic interference - would either stop the signal from the strings if under them or prevent you from playing at all if over them.

A single plate of conductive material will also shield against an alternating electric field to some degree by by creating a roughly constant potential in the region round it, particularly if it is grounded.

Humbucking seems to be the only line of defence against large magnetic fields. Stacked humbuckers or sidewinders are the most effective because of their better symmetry.

I would guess that ChatGPT must have the correct information about magnetic and electric shielding somewhere in its database but it only produces an output based on the probabilities of one word following another so it is tainted by the amount of drivel about pickups that it has been fed with from the internet. Lots of data, no knowledge but boldly stated and well written.

[cynical1]

I posed the same question to BARD, just out of curiosity. I even got a chart...:

"Humbucking pickups are designed to cancel out noise by having two coils that are wired in opposite polarity. This means that any noise that is picked up by one coil is also picked up by the other coil, but in the opposite phase. The two signals are then subtracted from each other, which cancels out the noise.

Conductive shielding is a metal sheet that is placed inside the guitar body. This sheet acts as a Faraday cage, which blocks electromagnetic fields from reaching the pickups. This can help to reduce noise from things like power lines, fluorescent lights, and cell phones.

The main difference between the two types of noise blocking is that humbucking pickups are more effective at blocking noise that is in the same frequency range as the guitar signal. Conductive shielding is more effective at blocking noise that is at a higher frequency, such as noise from power lines.

In general, humbucking pickups are a better choice for players who need to reduce noise in a variety of situations. Conductive shielding can be a good option for players who need to reduce noise from a specific source, such as a power line.

Here is a table that summarizes the differences between humbucking pickups and conductive shielding:

Feature	Humbucking Pickups	Conductive Shielding
Type of noise blocked	Noise in the same frequency range as the guitar signal	Noise at a higher frequency
Effectiveness	More effective	Less effective
Cost	More expensive	Less expensive
Installation	More difficult	Easier

Ultimately, the best way to reduce noise on your guitar is to use a combination of humbucking pickups and conductive shielding."

For posterity...

HTC1

[aquin43]

The same spurious confidence and lack of any understanding. I wonder where the idea of power lines being a source of high frequency noise comes from, and also a sheet constituting a cage.

Neither of the systems has picked up the difference between electric and magnetic sources of interference.

This is probably an unfair test. There are other systems of this sort that are trained on scientific data; presumably one of those could give a better answer.

[antigua]

May 3, 2023 8:38:20 GMT -5 aquin43 said:

The same spurious confidence and lack of any understanding. I wonder where the idea of power lines being a source of high frequency noise comes from, and also a sheet constituting a cage.

Neither of the systems has picked up the difference between electric and magnetic sources of interference.

This is probably an unfair test. There are other systems of this sort that are trained on scientific data; presumably one of those could give a better answer.

To kind of cut to the chase though, is it simply true that if guitar pickups were intended to receive RF instead of audio range, that the ratio of noise blocking provided by conductive shielding would be higher than it is? I think the question that drives people mad, even if they don't know it, is why conductive shielding is so important in various electrical applications, but not with electric guitar.

I know that per FCC regulation, part of the purpose of the shielding is to prevent an electrical device from emitting noise, and becoming an EMI/RFI pollution source. Could it be that shielding is meant to keep the noise in, more so than block noise out, and so the shielding is added expecting it to do reduce noise, when we're really just making our guitars more FCC compliant?

As for ChatGPT predicting the next word, I think it's more complicated than that, it weights importance/relevance of ideas, like it takes in a sentence and algorithmically cuts it up in order to find the important parts, so a lot of the mistakes I've seen it make seem to be related to me asking it one thing, and it thinking I want or need to know something else. Like I ask it about humbucking versus shielding, but it doesn't understand why that's important, so it takes related ideas that are deemed important otherwise, and presents that instead. I've seen people get the info they need by just changing the way they ask the question, because doing so gives the AI model a different clue as to what information is important to you. 

 

[ms]

Of course AI got it wrong.  There is not enough "I" there so that it can doubt what it learns by looking up things on the internet, and then go learn the physics in order to get it right.  AI now knows how to make things sound good to humans, and so for many things "I" means idiot, but many humans still think it is a near genius.  This is a very dangerous tool.

[aquin43]

A sad aspect of this is that the machines are reflecting the correlations found in the training information, to a large extent culled from the internet. Their responses indicate that most of the statements containing both "guitar pickups" and "shielding" that are out there are simply wrong.

I suppose we are used to that, anyway.

[gckelloch]

So, Al and Cu shielding in the control cavity is equally effective against noise we can't hear?

[ms]

May 3, 2023 16:32:28 GMT -5 gckelloch said:

So, Al and Cu shielding in the control cavity is equally effective against noise we can't hear?

And low frequency noise from electric fields that you can hear.  For example, if you do not ground the strings, you can hear hum with many pickups.  This is from electrical fields. It is not necessary to ground the strings if the pickup is very well shielded, but this usually means shielding the control cavity and cables as well.  Nickel silver works; you do not need either Cu or Al.

[reTrEaD]

May 3, 2023 17:32:49 GMT -5 ms said:

ground the strings

I don't know the science involved but we ugly bags of mostly water seem to act as a conduit to focus the fields that may exist in the environment surrounding the guitar. Grounding the strings is a convenient way of grounding us, which occurs when we touch the strings.

[gckelloch]

May 3, 2023 17:32:49 GMT -5 ms said:

May 3, 2023 16:32:28 GMT -5 gckelloch said:

So, Al and Cu shielding in the control cavity is equally effective against noise we can't hear?

And low frequency noise from electric fields that you can hear.  For example, if you do not ground the strings, you can hear hum with many pickups.  This is from electrical fields. It is not necessary to ground the strings if the pickup is very well shielded, but this usually means shielding the control cavity and cables as well.  Nickel silver works; you do not need either Cu or Al.

Is there NiAg paint? I was just talking about shielding the control cavity. It should also be noted that Al is paramagnetic and Cu is diamagnetic. Al has a different effect on tone than Cu. I have posted this link b4. It's worth a look:
alexkenis.wordpress.com/2016/04/13/guitar-pickup-theory-7-effect-of-pickup-cover-material-on-tone-and-noise/

[antigua]

May 4, 2023 9:17:37 GMT -5 gckelloch said:

Is there NiAg paint? I was just talking about shielding the control cavity. It should also be noted that Al is paramagnetic and Cu is diamagnetic. Al has a different effect on tone than Cu. I have posted this link b4. It's worth a look:
alexkenis.wordpress.com/2016/04/13/guitar-pickup-theory-7-effect-of-pickup-cover-material-on-tone-and-noise/

The purpose of the conductive shield is to be a direct path to ground for capacitively coupled noise, so all that is required is that it have low resistance relative the overall circuit impedance.

For magnetically inducted noise, the permeability, conductivity and thickness factor into how much dissipation occurs, so the metal allow would matter a lot more in that case, but the audio frequency noise is low frequency, so the metal would have to be thick, and would block out the guitar string signal if it were in between, and this is the kind of noise that humbucking addresses anyhow. 

I guess humbucking doesn't address capacitive noise because it will hit one coil more than the other most of the time, but that's just a guess, I'm fuzzy on that. 

[ms]

AK has a very thorough set of measurements.  It is fun to think about limiting cases.  A superconducting cover would dissipate no energy, but the induced currents would affect the inductance and therefore the resonance frequency.  So it  is not necessarily true higher conductivity affects the Q more than low in all cases.  However, I do not understand all of his results.

[stevewf]

May 2, 2023 19:37:55 GMT -5 antigua said:

what is the difference between the type of noise that is blocked by humbucking versus the type that is blocked by conductive shielding?

I've seen ChatGPT be wrong about all sorts of things, so I'm not implying what it's saying here must be correct, but it seems to basically be saying that the conductive shielding differs from humbucking in that it target high frequencies. It seems that humbucking works a lot better than shielding in the electric guitar context, is this simply because humbucking is more effective in the audio range, while conductive shielding is more effective in the high frequency range? The capacitance across the guitar's circuit is obviously high enough that audible sound is rolled off, let's say around 3kHz to 4kHz, isn't that filtering action grounding out high frequency noise, even if the shielding is omitted, or fails to block the noise?

Is there a test we can design? Bearing in mind that...

I've had unexpected things happen when the wiring was external to the guitar, when there's more distance between the components. I know that when I test my wiring changes with alligator clips for example, it seems much noisier than when it's all soldered down and closed up, even when the guitar in question has no shielding.

Could one take, say, a strat-type guitar with a single humbucker pickup, and wire switches so that we can hear:
-single coil
-humbucking pair of coils
-the above with cavity shielding grounded/not grounded
-the above with the player grounded/not grounded (via the strings)

[timtam]

Manfred Zollner did a 3-part youtube video series on shielding recently. Theory and experiments. In German as usual, but you can get the gist from youtube's closed captions/auto-translate to English.

[blademaster2]

May 3, 2023 7:24:56 GMT -5 aquin43 said:

When creating a cavity shielded against electrostatic interference, the type of material has virtually no effect as long as it is reasonably conductive.

I am sure you meant "electromagnetic" interference, right? Electrostatic is a charge that is built up in a material, not moving anywhere (static). If it moves from there to a place of differing charge/voltage then it is electrostatic discharge (ESD), like lightning. A one-time event usually.


I have only ever observed electrostatic 'discharge' causing noise in my guitar if I run my dry hands along the finish of the neck and my hand triboelectrically charges and then discharges to the neck surface and causes a crackling sound picked up somehow through the amp. I am not aware that shielding or humbuckers would prevent that but I have not tested for it.

As for the other points in this thread:

Humbucking is a cancellation of induced signals through the sum of two opposite polarity signals created by the reverse winding of one of the coils. Reversing the magnet polarity allows the induced string signal to sum with additive results rather than cancelation, so you hear the guitar signal. In theory this is not specifically for low frequencies, however there is a predominance of 50/60 Hz electromagnetic noise in the air so that is usually the source of the noise ('hum'). This cancellation technique is most effective for magnetic fields that shielding cannot 'block', but works for both electric or magnetic field noise.

Shielding on the other hand creates a faraday cage that prevents electric fields from being formed inside of it and is usually created with a braid on cables (or a metal enclosure or enclosure lined with conductive tape or paint). It blocks electric fields but cannot 'block' magnetic fields (they can only be canceled by humbucking or other differential technique). Braids do not provide 100% coverage, and they therefore probably have inductance, so they in theory work well at most frequencies up to a limit (far higher than human hearing). Shielding also must be 'zero' resistance/impedance to work perfectly, so the properties of the conductive material and its resistance/inductance will degrade from the ideal, hence the selection of copper versus aluminum versus conductive paint. Anything greater than zero (resistance or impedance) will allow some level of signal to exist inside.

[ms]

He does not mean electromagnetic (that is radio waves, for example), just electric.  For example, touch the tip on a guitar cable plugged into an amp.  Your body is at a different electric potential than the low side of the connector in the amp.

I do not see how a humbucker can cancel electric fields, only magnetic.

An electric shield does not have to be a very good conductor in order to do a very good job of shielding at audio frequencies.  The rate at which charge can be redistributed is a function of the capacitance involved and the conductivity of the shield, and thus the charge redistribution can be limited at very high frequencies, but not low.

[aquin43]

Jun 7, 2023 19:29:37 GMT -5 blademaster2 said:

May 3, 2023 7:24:56 GMT -5 aquin43 said:

When creating a cavity shielded against electrostatic interference, the type of material has virtually no effect as long as it is reasonably conductive.

I am sure you meant "electromagnetic" interference, right? Electrostatic is a charge that is built up in a material, not moving anywhere (static). If it moves from there to a place of differing charge/voltage then it is electrostatic discharge (ESD), like lightning. A one-time event usually.

The wavelength of a radio wave at 50Hz is 6000 km, so we are always in the "near field" where hum interference is concerned. This means in practice that the varying electric field may be modeled as an electrostatic problem who's intensity we then vary. So "electrostatic" where we are considering only the electric field and to distinguish it from the pure "electromagnetic" which has no useful application in this case.

[blademaster2]

Jun 8, 2023 3:00:06 GMT -5 aquin43 said:

Jun 7, 2023 19:29:37 GMT -5 blademaster2 said:

I am sure you meant "electromagnetic" interference, right? Electrostatic is a charge that is built up in a material, not moving anywhere (static). If it moves from there to a place of differing charge/voltage then it is electrostatic discharge (ESD), like lightning. A one-time event usually.

The wavelength of a radio wave at 50Hz is 6000 km, so we are always in the "near field" where hum interference is concerned. This means in practice that the varying electric field may be modeled as an electrostatic problem who's intensity we then vary. So "electrostatic" where we are considering only the electric field and to distinguish it from the pure "electromagnetic" which has no useful application in this case.

From my background I must disagree on this point for terminology. Even a DC electric field from a battery or capacitor, which has a wavelength of 'infinity', is generally not called electrostatic.  A DC electric field and the field from an electrostatic source might be the same thing in many respects, including being of infinite wavelength, but I have never seen the general use of these terms equated in my years of engineering practice and teaching engineering at university.

Perhaps the distinction in terminology stems from the source of the field, electrostatic usually being a triboelectric phenomenon or other induction method, or from the way the charge is stored and its source impedance since static electricity is usually a charge contained in a high impedance material or insulator rather than a good conductor.

Additionally, regardless of wavelength all of these fields - even DC fields created by a static charge - are electromagnetic. For DC fields whether from a static charge or a DC voltage source the magnetic component of the phasor has zero amplitude since the charge is not moving through space. I do not think James Clerk Maxwell made any distinction based on the wavelength.

At least that is what my engineering theory tells me.

[ms]

Dictionary
Definitions from Oxford Languages 
e·lec·tro·stat·ic
adjectivePHYSICS
adjective: electrostatic
relating to stationary electric charges or fields as opposed to electric currents.

When you limit "electrostatic" to charge in very good insulators and created by frictional or similar means, you are forced to use the term "electromagnetic" to describe the result of a motionless or near motionless charge distribution that can create no or no significant magnetic field.  That seems more confusing.

Dictionary
Definitions from Oxford Languages 
e·lec·tro·mag·net·ic
adjective
relating to the interrelation of electric currents or fields and magnetic fields.
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[aquin43]

Jun 11, 2023 18:02:47 GMT -5 blademaster2 said:

Jun 8, 2023 3:00:06 GMT -5 aquin43 said:

The wavelength of a radio wave at 50Hz is 6000 km, so we are always in the "near field" where hum interference is concerned. This means in practice that the varying electric field may be modeled as an electrostatic problem who's intensity we then vary. So "electrostatic" where we are considering only the electric field and to distinguish it from the pure "electromagnetic" which has no useful application in this case.

From my background I must disagree on this point for terminology. Even a DC electric field from a battery or capacitor, which has a wavelength of 'infinity', is generally not called electrostatic.  A DC electric field and the field from an electrostatic source might be the same thing in many respects, including being of infinite wavelength, but I have never seen the general use of these terms equated in my years of engineering practice and teaching engineering at university.

Perhaps the distinction in terminology stems from the source of the field, electrostatic usually being a triboelectric phenomenon or other induction method, or from the way the charge is stored and its source impedance since static electricity is usually a charge contained in a high impedance material or insulator rather than a good conductor.

Additionally, regardless of wavelength all of these fields - even DC fields created by a static charge - are electromagnetic. For DC fields whether from a static charge or a DC voltage source the magnetic component of the phasor has zero amplitude since the charge is not moving through space. I do not think James Clerk Maxwell made any distinction based on the wavelength.

At least that is what my engineering theory tells me.

Thinking more carefully about expressing my meaning, I might change it to "Electric Field Interference" as distinct from "Magnetic Field Interference". The connection with "electrostatic" is then that the effects of any displacement currents on the source of the interference are negligible so the field at any instant may be described and computed as an electrostatic one, even though it is varying in time.

I think that in the context of guitar pickups, the blanket use of the entirely rigorous "electromagnetic interference" simply makes it impossible to distinguish between the two separate problems with their very different solutions. This has been the cause of much confusion - not here, perhaps, but certainly in the world at large.

By the way, surely the field surrounding a battery is electrostatic. The chemical action in the battery causes a static separation of charge, pushing more electrons to the negative terminal.

[ms]

"Electric Field Interference", "Magnetic Field Interference":  Excellent, I will try to use these descriptions.