DC AND ACDirect current flows in one direction only, while
alternating current isconstantly changing in amplitude and
direction
8/17/2019 Ac Circuits L1
3/10
Current carrying conductors and magnetic fields
8/17/2019 Ac Circuits L1
4/10
The relation between the direction of the magnetic lines of
force around aconductor and the direction of electron current flow
in the conductor may bedetermined by means of the LEFT-HAN !"LE F#!
A C#N"CT#!$
if you gras% the conductor in your left hand with the thumb
e&tended in thedirection of the electron flow 'current( '- to
)(* your fingers will %oint in thedirection of the magnetic lines
of force+
For con,entional current we use !ight hand rule
irection of agnetic Field
8/17/2019 Ac Circuits L1
5/10
Magnetic field around current carrying conductor
The direction of the magnetic force is assumed to be the
directionin which the north pole of the compass points.
8/17/2019 Ac Circuits L1
6/10
Magnetic field around two parallelconductors
•If two parallel and adjacent conductors are carrying currents
in the same direction,
the fields about the two conductors aid each other.
•If the two conductors are carrying currents in opposite
directions, the fields about
the conductors repel each other.
8/17/2019 Ac Circuits L1
7/10
Fleming.s Left-hand rule forgenerators
8/17/2019 Ac Circuits L1
8/10
/AS0C AC 1ENE!AT0#N
2A current-carrying conductor %roduces a magnetic field around
itself
2Changing magnetic field %roduces an emf in a conductor that is
if aconductor is %laced in a magnetic field* and either the field
or the
conductor mo,es* an emf is induced in the conductor+ This effect
is calledElectromagnetic Induction.
