Electrical Circuits

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Electric current is measured in amps (A) using an ammeter connected in series in the circuit.

A

Slide 12

measuring current

A

A

This is how we draw an ammeter in a circuit.

SERIES CIRCUIT

PARALLEL CIRCUIT

Slide 13

measuring current

SERIES CIRCUIT

PARALLEL CIRCUIT

current is the same

at all points in the

circuit.

2A

2A

2A

current is shared

between the

components

2A

2A

1A

1A

Slide 14

copy the following circuits and fill in the missing ammeter readings.

?

?

4A

4A

4A

3A

?

?

1A

?

3A

1A

1A

Slide 15

Measuring voltage

The ‘electrical push’ which the cell gives to the current is called the voltage. It is measured in volts (V) on a voltmeter

V

Slide 16

Different cells produce different voltages. The bigger the voltage supplied by the cell, the bigger the current.

measuring voltage

Unlike an ammeter a voltmeter is connected across the components

Scientist usually use the term Potential Difference (pd) when they talk about voltage.

Slide 17

measuring voltage

V

This is how we draw a voltmeter in a circuit.

SERIES CIRCUIT

PARALLEL CIRCUIT

V

Slide 18

V

measuring voltage

V

V

V

Slide 19

series circuit

1.5V

voltage is shared between the components

1.5V

3V

Slide 20

voltage is the same in all parts of the circuit.

3V

parallel circuit

3V

3V

Slide 21

Measuring current & voltage

copy the following circuits on the next two slides.

complete the missing current and voltage readings.

remember the rules for current and voltage in series and parallel circuits.

Slide 22

measuring current & voltage

V

V

6V

4A

A

A

a)

Slide 23

measuring current & voltage