Here's a good question

Wana_make_a_guitar

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How do They work.
I know Pickups have something to do with magnets, but not much else.

In science i was learning about Super Conductors and how they use magnetic coils to power things, and was wondering, do some pickups use the same thing, but smaller.

The reason that i'm asking this is my science teacher, though not knowing how to play guitar very well at a basic level, is a complete nerd when it comes to all the electronics, and says i don't know enough about my own guitar to play it! :laughing7: So i'm going to see if he knows what you guys know, that'll show 'im!
 

Orpheo

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funny. thought about the same thing yesterday. having a superconductor as a coil (as a magnet has no use, doh), will give you an indefinite output. but you've gotta find a superconductive substance that will be superconductive up until 60 degrees celcius, otherwise, midway a performance, your sound will simply be gone :p
 

jmasin

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The guitar strings disrupt the magnetic field of the pole pieces, inducing a current in the coil.  It is similar to moving the magnet and creating the current (generator), but in this case the magnet is stationary and strings move, ultimately having the same effect.

 

blue313

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+1 to jmasin

excerpt from http://www.guitarnuts.com/wiring/pickups.php

How a magnetic guitar pickup works:
In the last few years, "active" pickups have come become more popular and piezeolectric "acoustic" pickups are beginning to catch on. However, probably 95% of electric guitars currently manufactured still use simple magnetic pickups -- the kind we'll describe here. These pickups work on the same principal as electric generators -- Whenever there is relative motion between magnetic flux lines and an electrical conductor (copper wire) an electrical signal will be generated in the conductor. The strength of the signal generated depends on how much (how many coils) of the conductor "cut" the magnetic flux lines, how fast the relative motion is, and on how strong those flux lines are.

Generators work because a coil of wire is rapidly rotated in a fixed magnetic field (or vice versa in some instances). So, why does a guitar pickup work? Neither the magnet nor the coil is moving or vibrating -- why do we still get a signal? Any time a ferous material is placed within a magnetic field, it will "warp" the magnetic flux lines. Therefore, when our steel guitar strings vibrate within the field of the fixed pickup magnet, they cause the magnetic field to "vibrate" as well. This creates motion of the flux lines relative to the coil of copper wire and generates an electrical signal.

We can make the generated signal stronger by either increasing the number of turns of wire on the coil, or by increasing the strength of the magnet. Unfortunately, pickup design is not this simple -- we'll discuss some of the factors later on.
 

TexxasJam

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Try these links:

http://entertainment.howstuffworks.com/electric-guitar1.htm

http://en.wikipedia.org/wiki/Pickup_%28music%29

:guitarplayer2:
 

TroubledTreble

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What I didn't see is that in fact one purpose of the magnet is to actually magnetize the strings. This becomes the moving magnet within the field of the coil. Cool stuff when you consider how old this technology is, how well it works for this purpose and how little it has changed.
 

Wana_make_a_guitar

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blue313, woah. That did make sense to me, but i had to read it three times to get it!

So the movement in the strings 'disturbs' the magnetic field of the Pup and gets a electric signal from it, that being said in the most simplest of forms.

So what would happen if a magnet was placed next to a Pup? Would the magnetic field increase depending on which magnetic pole, north or south, is closest? 
 

Orpheo

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TroubledTreble said:
What I didn't see is that in fact one purpose of the magnet is to actually magnetize the strings. This becomes the moving magnet within the field of the coil. Cool stuff when you consider how old this technology is, how well it works for this purpose and how little it has changed.

you don't magnetize the strings, the strings are metal, and made of a material that cán be magnetized, and thus they can change the magnetic field when in motion.
 

Orpheo

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Wana_make_a_guitar said:
The only metals that are magnetizable are steel, nickel, iron, cobalt, i think copper, and something else

funny huh. your strings áre made of nickel and steel!
 

blue313

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Wana_make_a_guitar said:
blue313, woah. That did make sense to me, but i had to read it three times to get it!

So the movement in the strings 'disturbs' the magnetic field of the Pup and gets a electric signal from it, that being said in the most simplest of forms.

So what would happen if a magnet was placed next to a Pup? Would the magnetic field increase depending on which magnetic pole, north or south, is closest? 

The output generated by an electric guitar is very weak compared to devices using similar principles like generators. The relative field strength would increase dependent on pole alignment and distance, but more string motion will create higher output as will other factors.  Too strong and the motion of the strings won't 'disturb' the field enough to generate 'good' output...and kill your sustain as the field dampens the vibration of the string.  A powerful field can impart "too much" on the strings and cause odd tones (wolf tones, Stratitis, etc.).   

It'll also interact with the field of the pup's magnet and cause its own sound to be generated as you move it (think of it as a super-duper guitar string).   EBow and Sustaniacs are examples.  EVH also used a drill near his pickups on "Poundcake" for another example.

However, putting another magnet near the pickup is generally not a great idea (especially with rare earth magnets).    It can mess up the pickup if its powerful enough to skew the placement of the magnet inside the pickup, or leave a residual (or foreign to its design) magnetic charge on the coils or polepieces.  Its a delicate balance that generates the sounds you know and love...(so experiment on crappy pups you were going to trash anyways)  :laughing7:
 

TroubledTreble

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Orpheo said:
you don't magnetize the strings, the strings are metal, and made of a material that cán be magnetized, and thus they can change the magnetic field when in motion.

I was trying to include that the strings are in fact magnetized. They are an extension of the magnetic field. It's all very symbiotic.

I was also aluding to the fact that the string must be made of a ferrromagnetic material.

:icon_thumright:
 

Orpheo

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Wana_make_a_guitar said:
Basically, magnets are an Electro magnet?

no, no no. an electromagnet is one big coil where a current runs through, and 'emits' a magnetic field :) thats an electro magnet
 

Orpheo

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Wana_make_a_guitar said:
Damn, I meant a Pickup is basically a electro magnet?

I should of read my post :doh:

oh boy... thats a tough one. in a sense, yes. the permanent magnet (the alnico2,3,4,5,8 or ceramic) is permanent. the string makes the magnetic field change, causing an induction current. that current causes its own magnetic field, called self inductance. that means that a pickup will be a bit more 'magnetic' when you start playing. this effect has to be taken into account when making a pickup, though this effect is VERY small.

but a pickup is not an electro magnet in the regular meaning of it: a coil with a current giving a magnetic field, making it a temporary magnet, which can be turned on and off at will.

the problem with a pickup being an el.mag is mostly due to the fact that the current isnt stable; it changes every second. the output of the current changes, and the frequency aswell. this due to, ofcourse, the thing we do; making MUSIC.
 

Wana_make_a_guitar

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Orpheo said:
Wana_make_a_guitar said:
Damn, I meant a Pickup is basically a electro magnet?

I should of read my post :doh:

oh boy... thats a tough one. in a sense, yes. the permanent magnet (the alnico2,3,4,5,8 or ceramic) is permanent. the string makes the magnetic field change, causing an induction current. that current causes its own magnetic field, called self inductance. that means that a pickup will be a bit more 'magnetic' when you start playing. this effect has to be taken into account when making a pickup, though this effect is VERY small.

but a pickup is not an electro magnet in the regular meaning of it: a coil with a current giving a magnetic field, making it a temporary magnet, which can be turned on and off at will.

the problem with a pickup being an el.mag is mostly due to the fact that the current isnt stable; it changes every second. the output of the current changes, and the frequency aswell. this due to, ofcourse, the thing we do; making MUSIC.

Ah

Not in a 'i don't understand' ah, but at 'ah, very interesting'.


This is great. My teacher is chuffed, i think I'll be passing this section of science in the top!


 

Wana_make_a_guitar

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Orpheo, it's my B'day soon, my aunt's got a guitar, which i assume is a strat, she knows nothing about. She got it as a present for my young cousin, but it's too big for him, so i might get it.

Also I'm getting my Cry Baby wah wah soon!

Whooooo to 14th B'day
 

Orpheo

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Wana_make_a_guitar said:
Orpheo, it's my B'day soon, my aunt's got a guitar, which i assume is a strat, she knows nothing about. She got it as a present for my young cousin, but it's too big for him, so i might get it.

Also I'm getting my Cry Baby wah wah soon!

Whooooo to 14th B'day

well, my congratulations :) that you may turn out to by a 'strapping young lad' ;) (I hope you get the in-joke :D ) anyway: I hope you get nice presents.

if you have questions about this subject, let me know. I study physics, and I might be able to help out :)
 
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