M R . D E N N I S E V A N G E L I S T A

TOPIC 2

ELECTRICITYTypes of

STATIC ELECTRICITY• The build up of an electric charge on the

surface of an object.

• The charge builds up but does not flow.

• Static electricity is potential energy. It does not move. It is stored.

CURRENT ELECTRICITY• is the rate of flow of electrons.

• It is produced by moving electrons and it

is measured in amperes.

• current electricity must flow through a

conductor, usually copper wire

ELECTRIC CURRENT

Types of

DIRECT

CURRENT

(DC)

DIRECT CURRENT (DC)

• Where electrons flow in the samedirection in a wire.

• Current always flows in the same direction between the two terminals.

• The positive and negative terminals are always positive and negative.

EXAMPLES OF DC

SOLAR PANELS

SOLAR-POWERED

STREET LIGHTS

ELECTRICAL BATTERY • is one or more electrochemical cells

that convert stored chemical

energy into electrical energy.

What's in a battery?

Batteries are made of four main parts:

A positive electrode (ih-lek-trohd). This

can be a chemical, such as carbon that

allows electric current to be generated.

A negative electrode, such as zinc, also

allows electric current to be generated..

An electrolyte (ih-lek-troh-lite), which is a

paste or a solution (a liquid with

something dissolved in it) that conducts

electricity.

A separator, which is a material that

insulates and separates the positive and

negative electrodes

BATTERIESTypes of

• primary batteries (disposable batteries)

• which are designed to be used

once and discarded.

• include zinc–carbon batteries and

alkaline batteries.

Batteries are made from chemicals found

in minerals.

Most of these minerals are heavy metals,

which can be poisonous even in very

small amounts.

A variety of standard sizes of primary cells. From left:4.5V multicell battery, D, C, AA, AAA, AAAA, A23, 9V multicell battery, (top) LR44, (bottom) CR2032

CR2032 OR CMOS BATTERY.

• secondary batteries (rechargeable batteries)

• which are designed to be recharged and used multiple times.

• include nickel–cadmium (NiCd), nickel–zinc (NiZn), nickel metal hydride (NiMH), and lithium-ion (Li-ion) cells.

CELLPHONE BATTERIES

LAPTOP BATTERIES

WARNING:

Batteries are hazardous waste.

ALTERNATING

CURRENT

(DC)

ALTERNATING CURRENT (AC)

• Electrons flow in different directions in a wire.

• The direction of the current reverses or alternates.

• Examples of generating AC: Powerplants

HYDRO-ELECTRIC POWERPLANTS

COAL POWERPLANTS

GEOTHERMAL POWERPLANTS

NUCLEAR POWERPLANTS

THERMAL POWERPLANTS

UNDERWATER TIDAL POWERPLANTS

WIND TURBINES POWERPLANTS

CIRCUITSTypes of