the insulations changes the windings?

The insulation changes the capacitance then?

The insulation changes the winding space?

Does the Bobbin Material change the LCR, flux, magnetic field?
it the Bobbin Material a permability?

 

Where is the ferromagnetism in a guitar pickup?
What does the ferromagnetism in a guitar pickup do?
Does the ferromagnetism change the flux,magnetic field or tone of a guitar pickup?


harmonic oscillator theory affects the resonance frequency? why and how?

A magnet with wire wrapped around it produces a "harmonic oscillator"?
what does this harmonic oscillator do?

 

the magnet exists in the pickup of an electric guitar. Think of an electric guitar pickup like a linear machine (or not if you are not machine orientated)



As you can see from this picture there are a number of poles (hence the linear machine analogy).

WHen nothing is changing a fixed flux is present in the pickups winding. When a string is plucked (the string MUST be ferrous to effect the field) it changes the magnetic proporties of the system and a changing flux occurs, a changing flux is a XFMR is current and it is this current that is then amplified

THe ferromagnetism as in the magnet present doesnt change the flux, it provides the flux, the strings of the guitar change the relunctance path that the flux can take.


bit confused what you mean here. Harmonic theory is used to calculate the resonant freq, thus they go hand in hand, one doesn't cause the other, it is the same thing just viewed from different angles


ok before I carry on you are going to be entering a world of pain if you really want to get into magnetism. Some of the cleverest ppl I have ever met work in electromag, it is a subject not for the faint harted.

Anyway to just desquell a myth, someone eariler on said that magentsDONT have different freq responses. Well in actual fact they do and it is mainly down to their hysteresis of the B-H curves (rare-earth mags have the worst) , but that is a different story and I dont want to confuse ppl too much.

Now depending what kind of magnet is being used.
Say we had a soft-iron magnet. Wrap a wire around it and put some current through it will cause the soft-iron magnet to become magentised to the field of the coil, the presece of the soft-iron will increase the permeability of the magnetic cct (think of it as a scaling factor)
Air has a perm of 4*PI*10-7
Iron has a perm of many thousand times higher then free air. Thus by adding iron to yr magentic cct you can increase the flux density conciderably (but it comes and limitation naimly saturation)

Now say you put a normaliron core into the coil. A normal iron core keeps it flux (ie a magnet). Now IF oyu put current into the winding one way you will basically canel out the magnet filed of the core and thus the inductance of the coil is zero, the other way you re-inforce the field and teh inductance goes up.

You cannot use MAGNETS in cores for tuned ccts due to this effect (soft iron MUST be used).
Now you increase the flux and you will cross a magic threshlod and you will start to magnetise the core.

Now start using stonger magnets (rare-earth and such) and the same is still true, current one way will cancel the flux (more and field will flop) current the other way and the field will strengthen.

The difference with rare-earth is if the flux get too heigh then their field actually collapsed and it is no longer magentic (well maybe 1% of its original strength)

So that statement abt a magnet with a coil around it being a harmonic oscillator isnt really possible since it will dampen out any oscillation very easily due to the sever mis-symattry of inductance one way to the other.

A soft-iron core will basically be a large inductor, and with in a LRC cct it will resonate at a certain freq

__________________
Nothing is impossible.
Once a problem is realised, the rest is just details

 

The inductance of a coil depends on the number of turns, the core material, its length and its diameter.
The capacitance of a coil depends on how many layers of turns, the spacing of its layers and turns, its length and its diameter.
The resonant frequency can be measured or calculated.

A magnet is not an inductor. A coil of wire is an inductor.

A magnet positioned inside a coil becomes the core of the coil. The ferrous core increases the inductance of the coil. The combination is an AC generator if the magnetic field is disturbed by moving the coil or magnet (dynamic microphone, magnetic phono pickup) or vibrating a steel string near it (guitar pickup).

__________________
Uncle $crooge

 

Ahh yes a moving-coil well that is a special case for a magnet within a coil, but then again that is just an electrical machine...

__________________
Nothing is impossible.
Once a problem is realised, the rest is just details

 

Thanks guys alot for helping me out

Whats inside a magnet?
Because there is so many different kinds of magnets and mixtures
the mixing process of making a magnet is a form of chemistry
so im wondering what these elements or materials do

Magnet Theory:
All a magnet does is generate a magnetic field with a fixed flux

Magnetic Field and Flux are they same thing?

ferromagnetism is inside the magnet?
The ferromagnetism is the Flux?

how does the current get amplified from a magnet and coil or wire?


"Harmonic theory is used to calculate the resonant freq"

How does a guitar pickup or a magnet with a coil have a resonant frequency or harmonic theory? what causes it to have a resonant frequency or harmonic theory?

 

The small current from a magnet and coil is amplified by a preamp circuit.

The combination of a coil's inductance and its capacitance (plus external capacitance) is a resonant parallel tuned LC circuit.

__________________
Uncle $crooge

 

What is a "harmonic oscillator" then applied to a guitar pickup or a magnet ?

 

But how does it form or get a small current from a magnet and a coil?

From just changing the Flux of the magnet it processes current?

The a Magnet is a Current generator?
But the output of a Guitar pickup is Voltage like mV so a guitar pickup is
a voltage generator?

 

Think of a guitar as a generator. REmeber how I said a electric guitar was like a linear-machine.


Say the strings are like the rotor moving and the stator is the pickup and the magnet provides the exitation flux.

As you put mechanical energy into the strings, this is transformed into electrical energy in the stator (ie the pickup)

it is an extrealy small amount of current, but it is enough for a dedicated electrical amplifier to work with

Also remebver that a resistor is a simple current->voltage converter, but that wont be what is being used

__________________
Nothing is impossible.
Once a problem is realised, the rest is just details

 

Thanks for the help

resistor is a simple current->voltage converter, but that wont be what is being used

Can u explain more about how a resistor generates current and converts it to voltage?


I'm still confussed what a "harmonic oscillator" is when dealing with magnets and coils?

i'm still confussed what "ferromagnetism" is when dealing with magnets and coils?

 

:shock:

Err the resistor doesn't generate current, the pickup generates the current as has already been explained. IF the pickup was "loaded" with a resistor, that current would have been converted into a voltage by the resistor to satify good-old OHM's law.

But as I said they wouldn't do that, some form of trans-impedance amplifier (but thats for photo-diodes???).

What are you confused with abt "harmonic oscillator" is when dealing with magnets and coils?

Equally "ferromagnetism" is when dealing with magnets and coils?
ferrous materials (ie ones with Iron in them) have the ability to enhance magnetic field by essensially acting as flux-guides. How do they do that?
The greatest mides on this planet for since magentism was first discovered until now dont fully understand why.

You get a coil and pass some current through it a magnetic field is produced (why? downto the electrons moving, the coil just concentrats them). Now that field goes everywhere. IF you put a piece of soft-iron in the core it acts as a flux-guid and concentrates all the flux down it

__________________
Nothing is impossible.
Once a problem is realised, the rest is just details

 

Thanks for the help

Are ferromagnetism a flux or magnetic field
what is a Ferromagnetism?
I thought ferromagnetism was inside a magnet

What is a harmonic oscillator? is it a flux or magnet field?
Where is a harmonic oscillator is it inside a magnet ?
What does a harmonic oscillator do?

 

Study about magnetic transducers and generators.

No! The combination of a magnet inside a coil makes the coil a generator when the magnetic field is disturbed.

When the current flows through a load, a voltage is developed across the load. Ohm's Law.

__________________
Uncle $crooge

 

Thanks alot for the information

Why does it Take a resistor or Load to convert current to voltage?

How does a resistor or Load convert current to voltage?
mostly a resistor need a ground to convert current to voltage
or a potential difference between - and +

Without resistors it would be just current and no voltage drops
without resistors there would be nothing to convert current to voltage