15 and its direction can determined the ‘dot’ ‘cross’ nota-
tion and the ‘screw rule’.
N S
N S
S N
Like poles repel
Unlike poles attract
FIGURE 5.14
The first laws magnetism.Basic Electrical Installation Work
114
Electromagnetism
Electricity and magnetism have been inseparably connected since the
experiments Oersted and Faraday the early nineteenth century. Imagine corkscrew screw
being turned that will move the direction the current. If
the current was going into the paper, shown Fig. 5.
. An
electric current flowing conductor produces magnetic field ‘around’
the conductor which proportional the current.15(a), the
magnetic field would spiralling anticlockwise around the conductor. this, think the current being repre-
sented dart arrow inside the conductor. The dot represents current
coming towards when would see the point the arrow dart inside
the conductor.15(b), the mag-
netic field would spiral clockwise around the conductor. The magnetic field ‘spirals’ around the conductor, shown
in Fig. Thus small current
produces weak magnetic field, while large current will produce strong
magnetic field. 5. 5. Therefore,
if the current was coming out the paper, shown Fig. The cross represents current going away from when we
would see the flights the dart arrow
