Electricity Lesson 5 Measuring Current in Series Learning

Learning Intention By the end of this lesson I will Develop my knowledge of

Starter Questions 1. What name is given to the type of circuit we investigated

Starter Answers 1. What name is given to the type of circuit we investigated

Measuring Current • We know that current is a flow of electrons and so

Measuring current • Current is measured using an ammeter. • The unit of current

Activity 1: Current in Series circuits What you need: • 1 battery, 2 bulbs,

Activity 1: Current in Series circuits Ammeter Position Current (A) 1 2 3 From

Plenary Questions 1. State what the missing values should be in the following circuits.

Plenary Questions 2. State what the missing values should be in the following circuit.

Plenary Questions 3. A pupil connected up this circuit. What’s the problem? The ammeter

Summary • • An ammeter measures current. The units of current are the ampere/amps/A

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Electricity Lesson 5 Measuring Current in Series

Learning Intention By the end of this lesson I will Develop my knowledge of measuring current Success Criteria • State how to measure current in an electrical circuit • State the unit of current • Construct an electrical circuit and accurately measure current flow in a series circuit

Starter Questions 1. What name is given to the type of circuit we investigated last day? 2. State what type of circuit each of the following are: A B 3. Which one of the circuits is being described below: “When I unscrewed one bulb, the other remained on”

Starter Answers 1. What name is given to the type of circuit we investigated last day? Parallel circuits 2. State what type of circuit each of the following are: A Series B Parallel 3. Which one of the circuits is being described below: “When I unscrewed one bulb, the other remained on” Circuit B - Parallel

Measuring Current • We know that current is a flow of electrons and so when we measure current, we are measuring how much electricity is flowing in a circuit. • The size of the current is measured using a meter called an ammeter. • The unit of current is the ampere (A). This is named after André-Marie Ampère (1775– 1836), who was a French mathematician and physicist. • In this section we will investigate the measurement of current in circuits.

Measuring current • Current is measured using an ammeter. • The unit of current is the ampere (A) although this is often shortened to “Amps”. The symbol for amperes is A. For example, a current of 3 amperes can be written as 3 A. • Ammeters have a circuit symbol: A • They must be connected in series in a circuit:

Activity 1: Current in Series circuits What you need: • 1 battery, 2 bulbs, 4 wires and an ammeter What to do: • Measure the current at three different positions by connecting the ammeter as shown in the circuit diagrams below:

Activity 1: Current in Series circuits Ammeter Position Current (A) 1 2 3 From the table, what can you say about the current at different positions in a series circuit? The current in a series circuit should be the same at every point.

Plenary Questions 1. State what the missing values should be in the following circuits. X = 0. 15 A Y = 0. 3 A

Plenary Questions 2. State what the missing values should be in the following circuit. A 1 = 2 A A 2 = 2 A A 3 = 2 A

Plenary Questions 3. A pupil connected up this circuit. What’s the problem? The ammeter should be connected in series.

Summary • • An ammeter measures current. The units of current are the ampere/amps/A Ammeters are connected in series. Current in a series circuit is the same at every point.