P2 5.1 ELECTRIC CIRCUITS

Difference between cell and battery?

Difference between an indicator lamp and a bulb?

1

2

3

4

5

Difference between cell and battery?

Difference between an indicator lamp and a bulb?

1

2

3

4

5

SYMBOLS FUNCTION

SYMBOLS

1

2

3

4

5

FUNCTION

1

2

3

4

5

SYMBOLS FUNCTION

1

2

3

4

5

SYMBOLS FUNCTION

1

2

3

4

5

SYMBOLS FUNCTION

6

7

8

9

10

SYMBOLS FUNCTION

6

7

8

9

10

SYMBOLS FUNCTION

6

7

8

9

10

SYMBOLS FUNCTION

6

7

8

9

10

SYMBOLS FUNCTION

6

7

8

9

10

SYMBOLS FUNCTION

6

7

8

9

10

SYMBOLS FUNCTION

Measuring Current

An Ammeter measures the sizeof the c………. .

It measures it in amperes(also called amps or A).

Are these componentsin series or in parallel?

k = ….. A

l = ….. A

m = ….. A

n = ….. A

0 = ….. A

p = ….. A

Bulbs in Series

A

* Bulbs in series are dimly lit

* If one bulb breaks the other goes out

Bulbs in Parallel

A

* Bulbs in parallel are bright

* If one bulb breaks the other stays on

Used in houses and car head lamps Used in some Christmas tree lights

Bulbs in Series

A

* Bulbs in series are dimly lit

* If one bulb breaks the other goes out

Bulbs in Parallel

A

* Bulbs in parallel are bright

* If one bulb breaks the other stays on

Used in houses and car head lamps Used in Christmas tree lights

Bulbs in Series

A

* Bulbs in series are dimly lit

* If one bulb breaks the other goes out

Bulbs in Parallel

A

* Bulbs in parallel are bright

* If one bulb breaks the other stays on

Used in houses and car head lamps Used in some Christmas tree lights

Is a torch circuit series or parallel ?

Measuring currents in circuits

An electric current is the flow of tiny charges called electronsaround a complete circuit.

We measure current in units called amps using an ammeter in series.

Build the following circuits and write down the ammeter reading:

0.4 A

0.2 A 0.2 A

A

1.

A A

A A

2.

A A

3.“Two bulbs in series are dim ”

4. A

A“Two bulbs in parallel are bright ”

5.

A

AMax current =

Min current = A

A

7.

6.

A

30 cm of thin wireA

60 cm of thin wireA

A

M

CURRENT The current flowing through acomponent in a circuit is measured inamperes (A) using an ammeterconnected in series with the component.

3A P

2A

1A

3A

A higher current means a greater flow ofelectrons.

At point P:

Current in at P =

Currents out at P

An experiment to show that current is a moving charge

Sensitive ammeter

Carbon coated ball on nylon thread

Van der Graff

generator

An experiment to show that current is a moving charge

Carbon coated ball on nylon thread

++_

___

The negative charges on the metal plate attract the ball

An experiment to show that current is a moving charge

Carbon coated ball on nylon thread

++_

___

The negative charges on the metal plate attract the ball

__

__

The ball receives negative chargeand is repelled away carrying the charges

across to the other plate

An experiment to show that current is a moving charge

The faster the charges are carried across from one plate to the other the greater the current flows:

Charge = Current X Time

Q = I X T

Coulombs Amps seconds

Charge = Current X Time

Q = I X T

Coulombs Amps seconds

Example: Calculate the amount of charge flowing passed a point in a wirecarrying a current of 5 Amps in 10 minutes.

Q = I X T

Q = 5 x 10 x 60Q = 3000 Coulombs of charge