Inductor question

[Kari]

So I was curious, what would be the result of winding an inductor around itself multiple times? As in at the end of the first coil, you wind the enameled wire back up around the coil and then down again several times? I don't really expect it to do anything out of the ordinary, just curious for a more seasoned hobbyist/professional's opinion.

 

[BobK]

Inductors are normally wound that way. The inductance is proportional to the square of the number of turns, so adding 1 layer to a 1 layer winding gives you about 4X the inductance.

Bob

 

[Kari]

Neat! So could you essentially create a supermagnet with a 9 volt battery?

 

[BobK]

Magnetic field is proportional to the number of windings and the current.

More windings = more resistance = less current, so it is not that simple.

Bob

 

[Kari]

So then the only way to make the magnet more powerful would be to increase voltage assuming resistance is constant?

Or are there other ways to increase current

 

[BobK]

More windings will increase the magnetic field if the same current is used, more current will increase the magnetic field if the same number of windings are used. The voltage needed to supply a given current depend on the resistance, which depends on the length (and inversely on the diameter) of the wire. More windings means more length, means more resistance. You can play with all of these things to increase the magnetic field.

Bob

 

[Kari]

was assuming there was already a multi layer inductor with a fixed number of windings, so constant resistance

 

[duke37]

You can play with the wire thicknes and number of turns but to get the same magnetic field, you will need the same power.
Get as much copper in there as is possible, if this is not good enough, use silver or a superconductor.

 

[Kari]

Perhaps someday i'll attempt something just for fun, like a big hollow inductor filled with metallic hydrogen.