ELECTRICAL CIRCUITS AND ELECTRICAL CIRCUITS AND COMPONENT SYMBOLSCOMPONENT SYMBOLS

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Some circuit symbolsSome circuit symbolsIn circuit diagrams components are represented by the following symbols;

cell battery

switch

lamp

motorammeter

voltmeter

buzzer

resistor

Circuit

Breaker

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The CELLThe CELL

The cell stores chemical energy and transfers

it to electrical energy when a circuit is

connected. When two or more cells are

connected together we call

this a Battery.

The cells chemical energy is

used up pushing a current

around a circuit.3

What is an electric current?

An electric current is the flow of electrons

through a circuit.

+ -

In which direction does the current flow? from the Negative terminal to the Positive terminal of a cell.

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simple circuitssimple circuits

Here is a simple electric circuit. It has a cell, a

lamp and a switch.

To make the circuit, these parts are connected

together with metal wires.

cell

lightswitch

wires

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simple circuitssimple circuitsWhen the switch is closed, the circuit is complete, and the lamp lights up. This is because there is a continuous path for the electric current to flow around.

If there were any breaks in the circuit, the current could not flow.

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circuit diagramcircuit diagram

cell switch

light wires

Electrical drawings are usually drawn using symbols;

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types of circuitstypes of circuits

There are two types of electrical circuits;

SERIES CIRCUITS PARALLEL CIRCUITS

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The components are connected end-to-end, one after the other.

Electrons flow in only ONE path.

SERIES CIRCUITS

If one bulb ‘blows’ it breaks the whole circuit and all the bulbs go out. 9

PARALLEL CIRCUITS

The current has a choice of routes (MANY paths).

The components are connected side by side.

If one bulb ‘blows’ there will still be a complete circuit to the other bulb so it stays lit.

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All information researched on the following web sites.

http://www.google.ca/search?q=electric%20circuit&rls=com.microsoft:en-ca&oe=UTF-8&startIndex=&startPage=1&gws_rd=cr&um=1&ie=UTF-8&hl=en&tbm=isch&source=og&sa=N&tab=wi

http://www.technologystudent.com/elec1/elecex.htmwww. Teachingzone.org (Electricity awareness course pack for teachers produced by C2B Media LTD