Hi!

Does the inductance of a coil on a closed core (ring core, EI-, EE-, UI-, UU-core) depend on the length of the coil? I guess not, because the magnetic length is the same.

Does it depend on the coil area if the core is the same? I guess not much since the additional area is an air core.

How different are inductors with straight and closed cores of equal length?

 

See Inductance Calculations by Frederick W. Grover, ISBN 9780876645574 or 9780486474403, 1948 & 2004 editions for a full treatise on the subject.

Cheers, DPW [ Everything has limitations...and I hate limitations.]

 

Hello,

Also a lot of information on coils and inductors can be found in the links of this page:
http://www.educypedia.be/electronics/coilsrelay.htm

Greetings,
Bertus

 

L=N^2/S

S=l/μ*A

where

L=inductance
N=number of turns
S=reluctacne
l=core length
μ=permeability of the core
A=cross sectional area of the core

The inductance depends on the length and the cross sectional area of the core. If the windings are not tightly winded then you have to include the air gap in your calculations.