NOTA-flux

1

Hmm..I forgot what the
teacher have taught me

yesterday…What is
Magnetic Flux??

2

Magnetic Flux

is

the number of
magnetic field
lines that pass
through an area,

A.

3

Let see.. Magnetic Field, B
The diagram
of Magnetic 4

Flux

Area,
A

AAnd…don’
t forget
about
this…

5

= � Normal
= ( ) of A
θ
Where
θ = angle between Normal of A and B B
B = Magnetic field strength
A = Surface area 6

Remember…
The angle must

be between
normal of an
area and the
magnetic field!

7

If I have a coil that Yes, and we
consists of a number of call it as

turns and having the magnetic flux
same area, will the linkage, Φ.
magnetic flux change??

8

FORMULA

Φ=
or

Φ= cos( )

where
B : magnetic field strength
A : area of the coil
θ : angle between B and normal of area A
N : numbers of turns for the coil
Ø : magnetic flux through one turn of a coil

9

Since magnetic flux is
a scalar product…the
minimum value must
be zero, am I right???

10

Correct ! Young man…
If angle is zero, (θ = 90°) where normal
of A is perpendicular to B,thus flux is

zero.
(Φ min = 0)
Because NO magnetic field lines cross
the surface.

B

11

But…
B when the angle is zero,

(θ = 0°)
where normal of A is

parallel to B,
thus flux is maximum.

(Φ max = BA)

Same goes to θ = 180°

12

B B
or or

B B

13

Magnetic Flux, wb decreasing
increasing

Note that : = 90° = 0° Time, s

cos 0° = 1 = 90°
90° = 0

14

Suggestion of methods to change
magnetic flux linkage, Φ:

Change the strength of the
Magnetic Field, B

Change the cross sectional area,
A

Change the angle by moving it, θ

15

Thank you..
Now, I understand more about magnetic flux..

It’s time for me to go out and play.

16