L> Solenoids as Magnetic Field SourcesSolenoid

A lengthy directly coil of wire can be supplied to geneprice a almost unidevelop magnetic field similar to that of a bar magnet. Such coils, dubbed solenoids, have actually an enormousnumber of helpful applications. The field canbe significantly strengthenedby the enhancement ofan iron core.Such cores aretypical inelectromagnets.

In the over expression for the magnetic field B, n = N/L is the number of transforms per unit length, occasionally referred to as the "transforms density". The magnetic field B is proportional to the current I in the coil. The expression is an idealization to an infinite size solenoid, yet provides an excellent approximation to the area of a long solenoid.

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Go BackSolenoid Field from Ampere"s LawTaking a rectangular path about which to evaluate Ampere"s Law such that the length of the side parallel to the solenoid field is L
provides a contribution BL inside the coil.The area is fundamentally perpendicular tothe sides of thepath, offering negligible contribution. If theend is taken so far from the coil that thearea is negligible, thenthe length inside the coilis the leading contribution.

This admittedly idealized instance for Ampere"s Law gives


This transforms out to be an excellent approximation for the solenoid area, especially in the instance of an iron core solenoid.

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At the facility of a lengthy solenoid

Active formula: click on the amount you wish to calculate. Magnetic area = permeability x rotate thickness x current
feature bcal()fh=document.forms<0>;def();nn=fh.nl.value;ii=fh.i.value;mm=4*Math.PI*Math.pow(10,-7);kk=fh.k.value;bb=mm*kk*nn*ii;fh.b.value=display(bb);fh.bg.value=display(10000*bb)feature pcal()fh=document.forms<0>;def();nn=fh.nl.value;ii=fh.i.value;mm=4*Math.PI*Math.pow(10,-7);bb=fh.b.value;kk=bb/(mm*nn*ii);fh.k.value=kkfeature ical()fh=document.forms<0>;def();nn=fh.nl.value;bb=fh.b.value;mm=4*Math.PI*Math.pow(10,-7);kk=fh.k.value;ii=bb/(mm*kk*nn);fh.i.value=iiattribute ncal()fh=document.forms<0>;def();bb=fh.b.value;ii=fh.i.value;mm=4*Math.PI*Math.pow(10,-7);kk=fh.k.value;nnl=bb/(mm*kk*ii);fh.nl.value=nnl;fh.n.value=fh.l.value*nnlfunction ul(l)fh=document.forms<0>;def();fh.nl.value=fh.n.value/lfeature un(nn)fh=record.forms<0>;def();fh.nl.value=nn/fh.l.valuefunction unl(nnl)fh=document.forms<0>;def();fh.n.value=fh.l.value*nnlfeature ub(bb)fh=record.forms<0>;def();fh.bg.value=display(bb*10000)function ubg(gg)fh=record.forms<0>;def();fh.b.value=display(gg/10000)function def()fh=document.forms<0>;if (fh.i.value==0)fh.i.value=1;if (fh.l.value==0)fh.l.value=.1;if (fh.n.value==0)fh.n.value=100;if (fh.nl.value==0)fh.nl.value=1000;if (fh.b.value==0)fh.b.value=.1;if (fh.k.value==0)fh.k.value=200feature display(x)xx=x;if(x.99*Math.pow(10,6))xx="...";return xx

For a solenoid of size L = m through N = turns, the revolve thickness is n=N/L= turns/m.

If the current in the solenoid is I = amperes

and the family member permeability of the core is k = ,

then the magnetic area at the facility of the solenoid is

B = Tesla = gauss.

The Earth"s magnetic area is about half a gauss.

The relative permeability of magnetic iron is roughly 200.

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Enter data, then click on the quantity you wish to calculate in the active formula above the information enattempt points. Default values will certainly be gotten in for unmentioned parameters, however the numbers will certainly not be forced to be continuous till you click the amount to calculate.

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