Fundamental Engineering Concepts - Mathematics and Statistics for the Environment - page 298

Direction of
flux expansion

Conductor 1

Flux expanding

Current

Conductor 2

Direction
of flux
collapse

Induced emf

Direction
of relative
conductor
motion

+

-

(A) (B)

FIGURE 11.63 Self-inductance.

(A) (B)

FIGURE 11.64 (A) Few turns, low impedance; (B) more turns, higher inductance.

(A) (B)

FIGURE 11.65 (A) Wide spacing between turns, low inductance; (B) close spacing between turns, higher
inductance.

together. The second coil, though shorter, has a larger inductance value because of its close
spacing between turns.

3. Coil diameter —Coil diameter, or cross-sectional area, is highlighted in Figure 11.66. The
larger diameter inductor has more inductance. Both coils shown have the same number of
turns, and the spacing between turns is the same. The first inductor has a small diameter,
and the second one has a larger diameter. The second inductor has more inductance than
the first one.

4. Type of core material —Permeability is a measure of how easily a magnetic field goes
through a material. Permeability also tells us how much stronger the magnetic field will be
with the material inside the coil.