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physics
Electrical safety awareness
Unit 15: Electrical Circuits and their Applications
C: Examine AC and DC production and health and safety aspects in domestic and industrial
applications
Section 1-AC and DC current
AC and DC current
DC stands for direct current. In DC current electrons flow only in one direction. AC stands for
alternating current. In AC the flow of electrons changes between 2 directions.
AC generators consists of field magnets, slip rings (are metal and insulated from each other), carbon
brushes and an armature (iron core wrapped with copper wire). The field magnets are cylindrical in
shape and concave. This is all connected to a galvanometer. When rotating the coil, a current is
induced in the coil. The galvanometer shows that the current is alternating. As this is rotating
perpendicular to the field an EMF (electromagnetic field) is induced. An electric current is then
induced in the coil. The direction of current shifts every half turn. The current flow is outputted in
the galvanometer. The arm on the galvanometer fluctuates indicating the current is alternating. The
voltage also reverses.
Mechanical energy is converted into DC electrical energy by DC generators. This generator consists
of stator magnets. They're essentially electromagnets with neighbouring poles that are polarised in
the opposite direction. They are in charge of creating the magnetic field. Armature. The armature is
a system of conductors or coils that are free to rotate on assisted bearings. Commutator. The
commutator is made of copper and has a cylindrical shape. It has two primary roles. One of which is
in charge of gathering current from the armature conductor. The other involves using brushes to
turn the armature's alternating current into a unidirectional current in the external circuit. Brushes.
Brushes are made primarily of carbon or graphite, and their primary purpose is to capture current
from a moving commutator. And the generator.
The stator is made up of two permanent magnets (north and south pole). Which is positioned so that
it fits around the rotor. The primary purpose of the stator is to generate magnetic fields that rotate
the rotor or armature coil. Armature loops are typically inserted into armature core slots. Armature
coils are made by linking a series of copper loops. The magnetic field is cut by the armature loop,
which causes an electromotive force (EMF) to be induced. The split ring is a movable unit that
, Taha Ismaeel
19080333
physics
reverses the current's polarity. The split ring is used to get only one direction of current. For each
half of rotation, the brushes must continuously change contact between the wires. The split ring is
used to keep direction of electrons to flow in 1 direction.
We did experiments to see how ac and dc current is produced.
Method
Get the solutions and the metals. Place the metal in the beaker connecting them using crocodile
clips. Use filter paper to allow the 2 solutions to meet (Fold into long rectangular shape). Record the
results.
Practical layout:
Method: