Electricity and Circuits

• Electrical energy or electricity is produced by the movement and distribution of these charged particles

1

The Flow of Charges

• Electrons orbit the nucleus

of an atom at different

disturbances often referred

to as levels.

• Each energy level contains

a particular number of

electrons at its maximum

2

The Flow of Charges

• Electrons in all energy levels

are held tightly in place and

are less likely to move to other

levels

* Electrons in the outermost energy level can jump from one atom to another quite easily

3

The Flow of Charges

• These jumps change the

overall charge of the atoms

• Changes in the distribution of

charges results in what is

commonly called electricity

4

Electric Current

• Electric current is the flow of

electric charges

• Electric current is measured in

amperes or amps

• Electric charges will always flow from a

region of higher potential energy to a region of lower potential energy

5

Electric Current

• The difference in potential

energy between two

locations is known as

potential difference

• Potential difference results

from difference in the

electrical charges in two locations

6

Electric Current

• Potential difference is

called voltage and is

measured in units called

volts

7

Electric Current

• A battery is a device that

converts chemical energy

into electricity

• In batteries, the potential

energy difference is

created by the positive and negative terminals

8

Circuits

• A circuit is a path through

which electricity can flow

• Charges will flow in a circuit

when there is potential

difference

9

Circuits

• Most circuits have three

parts:

1.An energy source

2.One or more loads

3.Conductors that connect

the two

10

Circuits

• A circuit may

also have a

switch that can

be open, which

stops the flow of

current, or closed

which allows current to flow

11

Circuits

• Energy flows only

through a circuit that is

closed

• Opening a circuit stops

the movement of

charged particles that produces an electric current

12

Energy Source

• A circuit needs an energy

source to push a charge

through the circuit

• A battery creates a potential

difference between its

negative and positive terminals

13

Energy Source

• Electric charges are repelled

by the negative terminal

and attracted toward the

positive terminal

14

Loads

• A load is a device in a circuit that

operates using electrical energy

• Examples of loads are light bulbs,

bells, radios, and motors

15

Conductors

• A conductor is a

material that allows

electrical energy to

flow through it easily

• Wires drawn from

metals are most often

the conductors in circuit

16

Conductors

• Wires carry electrical

current from the

energy source to the

load or loads that

are part of the

circuit

17

Resistors

• A resistor is an object added to a circuit that restricts the flow of electrical energy• Resistors inhibit the flow of electric current by providing a voltage drop when current

passes through them

18

Conductors

• Resistors can be used to

produce a desired

potential difference

• They limit current and

cause some electric

energy to be given off as

heat

19

Switch

• A switch is a device that is used

to control the flow of current

through a circuit

• A switch works by separating

(open) or bringing together

(closed) two conductors attached

to the circuit

20

Switch

• When the switch is open, the path that the electric charge can follow is broken so no electricity flows through the circuit• When the switch is closed it creates a continuous path through which an

electric charge can flow

21

Series Circuits

• Circuits can be set up in

series or in parallel

• A series circuit is a

circuit that provides

only one possible path

for the flow of current

22

Series Circuits

• In a series circuit, the loads

are set up in a series, or

line, that requires current

to flow through one load

before passing through the

next

23

Series Circuits

• Electricity flows from the battery

through each bulb, through the

switch and then back to the

battery

• Electricity in a series circuit has

only one path to follow

24

Series Circuits

• A failure or break in any part of

the circuit, such as a burned out

bulb or an open switch, will stop

the flow of electricity through

the entire circuit

• All loads share the same energy

source

25

Series Circuits

• This means that the current

lowers as more loads are

added to the circuit

• If these loads are bulbs,

adding additional bulbs can

cause the light given off by

the bulbs to be dimmer

26

Parallel Circuit

• A parallel circuit offers

more than one path for

the flow of electricity• An example of a parallel

circuit that has two paths for electrical current

• Each load in a parallel circuit has its own

closed circuit pathway to the energy source

27

Parallel Circuit

• Which means each load

has its own path for

electricity

• Because a parallel circuit

provides more than one path for electricity, a failure in one part of the circuit will not affect another part of the circuit

28

Parallel Circuit

• If a bulb burns out in one

path, current can continue

to flow through the circuit

by following another path

• The loads in a parallel circuit do not share

current in the way that loads connected in series will share

29

Parallel Circuit

• Each load connected to a

parallel circuit uses the full

voltage of the energy

source

• Adding more parallel loads

to the circuit does not affect the current flowing through the other loads

30

Parallel Circuit

• The lights will not be dimmer

as more lights are

attached

31