It is possible to calculate the self-inductance for circuits with simple
geometries Let us calculate the self-inductance of a long solenoid of cross-
sectional area A and length l, having n turns per unit length The magnetic
field due to a current I flowing in the solenoid is B = m0 n I  (neglecting edge
effects, as before) The total flux linked with the solenoid is
(
)(
)( )
0
NB
nl
n I
A
Φ
µ
=
0n2AlI

where nl is the total number of turns