1. Nicola Tesla: Mad Electricity
Basic Electricity
Nicola Tesla: Mad Electricity

2. Lesson 1 : Circuit Symbols
Draw and identify the circuit symbol for a battery, lamp, switch, resistor, motor, and variable resistor.
State that lamps, heaters and motors and buzzers convert electrical energy into other forms.

3. Lesson 1 : Circuit Symbols
Examine examples of circuit components and produce a poster matching pictures of components to their symbols and energy conversions.

4. Electrical Energy Converters
What are the energy conversions associated with each of these devices?
Loudspeaker
Microphone
Hair straighter TV
Lift going up
Heater
Lamp
electrical  sound
sound  electrical
electrical  heat
electrical  sound + light
electrical  kinetic +
potential
electrical  light + heat
Now watch this short video: Electricity and circuits

5. Lesson 2/3: Practical Circuits - Quiz Board

6. Lesson 2/3: Practical Circuits - Traffic Lights

7. Lesson 2/3 – Practical circuits - Electroplating

8. Lesson 4,5 Electrical measurements in circuits
State that an ammeter is used to measure current in Amps.
Draw and identify the circuit symbol for an ammeter.
Draw a circuit diagram showing the correct position of an ammeter in the circuit.
State that current is a flow of charge and is measured in amperes
State that an voltmeter is used to measure voltage in Volts
Draw and identify the circuit symbol for a Voltmeter.
Draw a circuit diagram showing the correct position of a voltmeter in the circuit.
State that voltage is the electrical push and is measured in Volts.
State that the voltage is the same for all components connected in parallel.

9. Lesson 4 : Electrical measurements – Series circuit – Xmas Tree Lights
Xmas tree lights are wired in series – in a line one after the other.
Connect three bulbs in series as shown in the diagram.
Use retort stands as model tree!
You will need:
Connecting wire
3 x Bulb holders with 2.5v lamps
6V battery
1 x retort stands and clamps
Wire strippers

10. Measuring currents in the circuit
What is current?
Programs / Virtual Int1 Physics / Practical Electricity / Current
Watch as you are shown how to measure the currents in the circuit you have just built.
Now go and measure the currents from the battery and through each of the lamps.
Can you notice a pattern?
The current is the same at all points at all points in the circuit
video clip: How to use a multimeter

11. Measuring Current 2A ?A ?A 2A 2A ?A
Current is the flow of tiny electric charges around a circuit.
An ammeter is used to measure the current through a circuit, measured in amperes (A)
To connect an ammeter we have to break the circuit and put the ammeter in series with the other components.
The size of a current in a series circuit is the same at all points in the circuit 2A ?A ?A 2A 2A ?A

12. Measuring voltages in the circuit
Watch as you are shown how to measure the voltages in the circuit you have just built.
Now go and measure the voltages across the battery and each of the lamps.
Can you notice a pattern?
The voltages in a series circuit add to equal the battery voltage (or very similar!)

13. Measuring Voltage in series
Voltage can be thought of as the 'push' it exerts on charges in the circuit. A bigger voltage means a bigger 'push', resulting in a larger current
A voltmeter is used to measure voltage, in volts (V)
Voltmeters are connected in parallel to either side of the component.
The size of the voltage across the battery in a series circuit is equal to the sum of the voltages across the other components. 6V ?V 3V ?V 3V ?V

14. Lesson 5 : Electrical measurements in a parallel circuit – street lights
Street lights are wired in parallel and are controlled by a time switch driven by a clock. This turns the lights on and off at the correct time.
Connect three bulbs in parallel as shown in the diagram.
Use retort stands as model lamp posts.
You will need:
Connecting wire
3 x Bulb holders with 6v lamps
6V battery
3 x retort stands and clamps
Wire strippers
What are the main advantages of wiring street lamps in parallel?

15. Measuring voltages in the circuit
Watch as you are shown how to measure the voltages in the circuit you have just built.
Now go and measure the voltages across the battery and each of the lamps.
Can you notice a pattern?
The voltages in a parallel circuit are all the same (or very similar!)

16. Measuring Voltage
The size of the voltage across the battery in a parallel circuit is equal to the voltages across the other components. ?V 6V ?V 6V ?V 6V

17. Measuring currents in the circuit
Watch as you are shown how to measure the currents in the circuit you have just built.
Now go and measure the currents from the battery and through each of the lamps.
Can you notice a pattern?
In a parallel circuit the current from the battery equals the sum of the currents through the lamps (or very similar!)

18. Measuring CURRENT in a parallel circuit
the size of the current from the battery equals the sum of the currents through each of the other components. ?A 4A 2A ?A ?A 2A 4A ?A
video clip: Lighting Circuit

19. Advantages of wiring street lamps in parallel:
When bulbs are connected in parallel each bulb gets the full battery voltage.
Each bulb lights with equal brightness.
If one or more bulbs stop working or are removed the rest continue lighting.

20. Series v parallel show-me exercise
You will see statements appear that may apply to SERIES circuits or PARALLEL circuit. Which is it?
PARALLEL
SERIES
These have no branches or junctions
If one bulb breaks, the other bulbs in other
branches stay on.
Can be turned on and off by a single switch
anywhere in circuit
If you put more bulbs in they will be dimmer
as it is harder for the current to get through- the resistance is higher
Switches can be put into the circuit to turn on and off all or part of the circuit.
The sum of voltages across all the components is equal to the voltage across the cell or battery
These have branches and junctions
If one bulb breaks, all the others go out.
If you put more bulbs in they will stay bright
The size of current flowing in different parts of the circuit can be different.

21. Ammeter and Voltmeter Exercises
Redraw each of the following diagrams and on each,
Add a meter to find the voltage across component E
Add a meter to find the current through component F
Now complete the exercise, “Measuring current and voltage in series and parallel circuits”

22. Current and Voltage Clips
Current and voltage in a circuit.
Current and Voltage in a series and parallel circuit

23. lesson 7/8: Ohm’s Law - Resistance
Conduct an experimental investigation of the relationship between voltage and current through a resistor.
State that voltage/current = constant
State that the “constant” is called the “resistance”
State that resistance is a measure of the opposition to the flow of current in a circuit.
State that resistance = voltage/current is called Ohm’s law.
Calculate resistance using Ohm’s law

24. INVESTIGATION: How does changing the voltage affect the current ?
In this experiment you will use battery voltage to push current through a resistor.
You will use an ammeter and a voltmeter to find how changing the voltage affects the current.
Follow the instructions on the worksheet, “Voltage, Current and Resistance”

25. Ohms Law 2 Number of batteries Voltmeter reading (Volts) Ammeter
(Amps) 1 2 3 4

26. Ohm’s Law - Resistance
An experimental investigation of the relationship between voltage and current through a resistor shows that
voltage/current = constant.
this is called Ohm’s Law
The “constant” is called the “resistance”.
Resistance is a measure of the opposition to the flow of current in a circuit.

27. Calculating resistance from ammeter and voltmeter values
Calculate resistance using:
resistance =
voltage
current
Example:
The current through a resistor is 0.1 amperes when the
voltage across it is 12 volts. Calculate the resistance.
12V
0.1A
voltage
current 12
0.1 =
resistance =
= 120W

28. Ohms Law Practice
1. A resistor has a voltage across it of 12 volts and a current through it of 2.5 amperes.
Calculate the resistance of the resistor Solution
2. A voltage of 6 volts is across a resistor where the current is 0.5 amperes.
What is the value of the resistor? Solution
3. Calculate the resistance of a component when a voltage of 24 V causes a current of 0.1 amperes Solution
5. A torch bulb is marked "6 V, 0.25 A".
Calculate the resistance of the bulb Solution
Practical Problems involving resistance

29. Calculate the resistance of the resistor.
1. A resistor has a voltage across it of 12 volts and a current through it of 2.5 amperes.
Calculate the resistance of the resistor.
voltage
current
resistance = 12 =
2.5 =
4.8 W
Beath High School - Int 1 Physics

30. 2. A voltage of 6 volts is across a resistor where the current is 0
2. A voltage of 6 volts is across a resistor where the current is 0.5 amperes.
What is the value of the resistor?
voltage
current
resistance = 6 =
0.5 =
12 W

31. 3. Calculate the resistance of a component when a voltage of 24 V causes a current of 0.1 amperes.=
0.1 =
240 W

32. 4. A torch bulb is marked "6 V, 0.25 A".
Calculate the resistance of the bulb.
voltage
current
resistance = 6 =
0.25 =
24 W

33. lesson 9: Practical problems involving Resistors
Draw and identify the circuit symbol for a resistor and a variable resistor.
State that resistors convert electrical energy into heat energy.
State that an ohmmeter is used to measure resistance.
State that resistance is measured in ohms.
State that an increase in resistance of a circuit leads to a decrease in the current in the circuit.
Give two practical uses of resistors.

34. Practical uses of resistors 1
The most common use for a resistor is simply to control the size of the current flowing in part of a circuit.
The larger the resistance the smaller the current.
The smaller the resistance the larger the current.
Resistance is measured in units of ohms (Ω)
Symbol for resistor:
Symbol for variable resistor:

35. Practical uses of resistors 2
Dimmer Switch
Fan Speed
Scaletrix controller
Petrol Gauge
Heating Element
Radio volume control
Skin Resistance – Lie Detector