Download ac / dc

What we will do today:
• Investigate the two ways in which current
moves around a circuit (a.c. and d.c.)
• State whether the mains supply is a.c. or
d.c.
• State whether a battery supply is a.c. or
d.c.
• Use an oscilloscope to see the patterns of
a.c. and d.c.
• Look at energy changes in electronic
components.
Electric current
•
Electric current is sent round a circuit in
two different ways:
1. Direct Current (d.c.): when electrons
flow around a circuit in one direction.
• A battery supply is an example of d.c.
2. Alternating Current (a.c.): when
electrons move both forwards and
backwards in a circuit, changing direction
many times in each second.
• The mains supply is an example of a.c.
The oscilloscope
•
•
An oscilloscope is used to draw a graph of an
electric signal.
It shows the following patterns for d.c. and a.c.:
d.c.
a.c.
Revision of Energy Types
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MACHELPS
M ovement (kinetic)
A tomic
C hemical
H eat
E lectrical
L ight
P otential
S ound
Energy transformations:
• Whenever
there is an
electrical
current in a
component,
there is an
energy
transfer.
Electrical
component
Energy
transformation
Buzzer
Electrical Energy →
Motor
Electrical Energy →
Resistor
Electrical Energy →
Lamp
Electrical Energy →
2005