Alternating Current
Direct Current
Components of Electrical
System

Voltage source = generator/batteries
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Conductor = wires

Control Element = switch

Load = light bulb, motors, appliances
Alternating Current

Electrons flow back and forth 60 times per second

Electrons travel in bidirectional path in circuit
EXAMPLES
Power generated from power plant
Travels over long distance to your home or business
VOLTAGE amounts 120v 208v 240v 480v
Advantages?
Disadvantages?
Direct Current


Maintains a constant value
Electrons travel in a Unidirectional path, point to point
EXAMPLES
Batteries are the most common source of DC
Primary Cells are intended for 1 use
Secondary Cells can be recharges for multiple use
Battery Construction

In its simplest form a battery
consists of two different metal
(copper&zinc) plates called
electrodes which are dipped
into an acid solution called
electrolytes

The cell then produces current
through the path of the two
metals
Battery types

Primary cells

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Nonrechargeable

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Alkaline
Carbon-Zinc
Lithium
Mercury
Silver-Oxide

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Secondary cells
Rechargeable
Lead-Acid
Nickel-Iron
Nickel-Cadmium
Lead-Calcium
Silver-Zinc
ELECTRICAL SYMBOLS



Wire

Load
Switch

Battery
Lamp

AC power