Benjamin Franklin and Thomas Edison were important figures in the development of electricity. Franklin proved that lightning was electricity and helped people understand electrical principles, while Edison invented the light bulb. The document goes on to define key electrical concepts like current, voltage, resistance and different types of circuits. It also describes different sources of electricity like power stations and batteries, as well as instruments used to measure current and voltage.

1. ELECTRICITY

2. PEOPLE
Benjamin Franklin
Thomas Edison
 Have you heard of these people?
 Why are they important?

3. Benjamin Franklin
 Proved that lightning was electricity by flying a
kite in a lightning storm
 Helped people understand the principles of
electricity
• Thomas Edison
– Invented the electrical light bulb

4. Definition:
Electricity is a form of energy that can
be easily changed to other forms.
What isElectricity???

5. WHERE DOES ELECTRICITY COME FROM?
Mainly 2 sources:
1) Power Stations
- Supply a lot of electricity
- Used in many electrical
appliances
2) Electric Cells (batteries)
- Supply a little electricity
- Portable
- Safe

7. HOW DOES AN ELECTRICAL APPLIANCE WORK?
 To make an electrical appliance work, electricity must
flow through it.
 The flow of electricity is called an electric current.
 The path along which the electric current moves is called
the electric circuit.

8. What is an Electric Current???
Definition:
An electric current is the rate of flow of electric
charges in a circuit.
connecting
wire
electric
cell
filament
flow of electrons

9. ELECTRIC CHARGES
 Electric charges are made up of positive
charges (protons) and negative charges
(electrons).
 When these charges flow in a circuit, a
current is produced.

10. HOW DOES ELECTRICITY FLOW?
 The battery in a circuit gives energy to the
electrons and pushes them around a circuit,
from the negative terminal of the cell, round the
circuit and back to the positive terminal of the
cell.

11. HOW TO MEASURE CURRENT?
 The SI unit for electric current is ampere (A).
 Smaller currents are measured in
milliamperes (mA).
 Different electrical components and
appliances require different sizes of current to
turn them on.
1 A = 1,000 mA
1 mA = 0.001 A

12. INSTRUMENT TO MEASURE CURRENT
 An ammeter is an instrument used for measuring
electric current.

13. AMMETER
 It must be connected in series in the circuit.
 Positive side of ammeter must be connected
nearest to the positive terminal of the battery
(electric cell), and vice versa.

15. VOLTAGE
 An electric cell gives energy to the electrons and
pushes them round a circuit. Voltage is a measure of
how much energy the electrons receive.
 Different voltages are supplied by different cells and
batteries.
12V CarBattery
1.5V Dry Cell
9 V DryCell

16. HOW TO MEASURE VOLTAGE?
The SI unit for voltage is volt (V).
A voltmeter is an instrument used for measuring
voltages.

17. VOLTMETER
Voltmetersmust be connected in parallelto the
circuit.
The positive side of voltmeter is connectedto the
positive terminalof the cell,and viceversa.

18. DIFFERENCE BETWEEN VOLTS AND AMPS
 Example – you could say
that…
 Amps measure how much
water comes out of a hose.
 Volts measure how hard
the water comes out of a
hose.

19. 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
2A2A
1A
1A

20. measuring voltage
PARALLEL CIRCUIT
SERIES CIRCUIT
• voltage is the same
at all points in the
circuit.
• voltage is shared
between the
components

22. RESISTANCE
Whenan electric currentflows through a circuit, there will be
some resistance that opposes it. (similartofriction)
It can be measured by dividing voltage by the current.
R =
V
I
R = Resistance
V = Voltage
I = Current

23. RESISTANCE
Goodconductors of electricity have LOW RESISTANCE.(Eg.
Metal objects)
 Electricity is able to flow through them veryeasily
Poor conductors of electricity have HIGH RESISTANCE. (Eg.
Wood, cloth)
 Electricity is not able to flow through them easily

24.  TheSI unit for resistance is ohm ()
 Different electrical components have different resistance
 Forexample, nichrome wires have a higher resistance than copper wires.
Resistance
So shouldwe use nichrome or copper
to make wires?

25. EXAMPLE 1
An electricrice cooker operates at 240 V anduses a
current of 8 A. What isthe resistanceof the rice cooker?
Voltage (V) = 240 V
Current (I) = 8 A
R =
V
I
R =
240
8
= 30 

26. RESISTORS
 An electrical component that is specially made to have a
certain resistance is called a resistor.
 They can be connected in a circuit to resist the current
flow.

27. FIXED RESISTORS AND VARIABLE RESISTORS
 Fixed resistors have only one resistance value
 Variable resistors can be adjusted to change the
resistance.
fixed resistor symbol variable resistor symbol
•Variable resistors are
usefulin light dimmers
andother electric
appliances

28. S/E:RESISTORS
Resistors canbe connectedin seriesor parallel
single resistor
extra resistor in
series results in
dimmer bulb
extra resistor in
parallel results
in brighter bulb
Resistors connected
in SERIES
Resistors connected
in PARALLEL

29. S/E: RESISTORS IN SERIES
 When resistors are connected in
series, the resistance willadd up and
increase.
 R = R1 + R2 + R3…
2  3 
The total resistance for this circuit is:
2  + 3  = 5 

30. S/E: RESISTORS IN PARALLEL
 When resistors are
connected in parallel, the
resistance will decrease
 This is because they will
provide alternate routes for
the current to flow.

31. S/E: RESISTORS IN PARALLEL
6 
6 
1
R
=
1
R
1
R
1
R
+ +
1 2 3
What is the resistance of the
circuit?
1
R
=
1
6
1
6
+
1
R
=
2
6
1
3
= R = 3 The final resistance
is smaller

32. WHAT WE KNOW...
Definition Units Symbol
Current The rate at which electrons
move from one place to
another
Ampere (A) I
Voltage
(Potential
Difference)
Measures the amount of
energy given to electrons to
move them
Volt (V) V
Resistance Degree to which a
substance opposes the
flow of electric current
through it
Ohms (Ω) R

33. DC CURRENT
 Direct current is the one way flow of
electrical charge from a positive to a
negative charge.
 Batteries produce direct current.
 Direct Current is different than alternating
current because the charge only flows in
one direction.
 Thomas Edison is credited for promoting
direct current.

34. ALTERNATING CURRENT
 Alternating Current is when charges flow back and
forth from a source.
 It is the way we receive our electricity (for our
houses, businesses, etc.)
 Nikola Tesla was a pioneer in the advancement of
alternating current.
 AC flows in the form of a sine wave, back and forth.
 It is easier to transform voltages in AC.
 The purpose of transformers is to convert AC
voltages.
 Transformers are extremely important to AC
current, and our life.

35. Alternating Current Direct Current
Amount of energy that can
be carried
Safe to transfer over longer
city distances and can
provide more power.
Voltage of DC cannot travel
very far until it begins to
lose energy.
Frequency
The frequency of alternating
current is 50Hz or 60Hz
depending upon the
country.
The frequency of direct
current is zero.
Direction
It reverses its direction
while flowing in a circuit.
It flows in one direction in
the circuit.
Current
It is the current of
magnitude varying with time
It is the current of constant
magnitude.
Types
Sinusoidal, Trapezoidal,
Triangular, Square.
Pure and pulsating.
Obtained from A.C Generator and mains. Cell or Battery.

36. NONRENEWABLE
AND
RENEWABLE
RESOURCES

37. HMMMM....
What do you think
nonrenewable
resources are?
Break it down...
Nonrenewable?
Resource?

38. NONRENEWABLE RESOURCES
A nonrenewable resource is a natural
resource that cannot be re-made or
re-grown at a scale comparable to its
consumption.

39. NUCLEAR ENERGY
Nuclear fission uses
uranium to create
energy.
Nuclear energy is a
nonrenewable
resource because
once the uranium is
used, it is gone!

40. COAL, PETROLEUM, AND GAS
Coal, petroleum, and
natural gas are
considered
nonrenewable because
they can not be
replenished in a short
period of time. These
are called fossil fuels.

41. HOW IS COAL MADE
???

42. HOW ARE OIL AND GAS MADE
???

43. WHAT WAS THE DIFFERENCE BETWEEN COAL
AND OIL/GAS?

44. HMMMM....
If nonrenewable
resources are resources
that cannot be re-made
at a scale comparable
to its consumption, what
are renewable
resources?

45. RENEWABLE RESOURCES
Renewable resources are
natural resources that can be
replenished in a short period
of time.
● Solar ● Geothermal
● Wind ● Biomass
● Water

46. SOLAR
Energy from the
sun.
Why is energy
from the sun
renewable?

47. GEOTHERMAL
Energy from
Earth’s heat.
Why is energy
from the heat of
the Earth
renewable?

48. WIND
Energy from
the wind.
Why is energy
from the wind
renewable?

49. BIOMASS
Energy from
burning organic
or living matter.
Why is energy
from biomass
renewable?

50. WATER OR
HYDROELECTRIC
Energy from the
flow of water.
Why is energy of
flowing water
renewable?

51. SUMMARY
What are the
differences
between
nonrenewable and
renewable
resources?

52. THERMAL POWER STATION
A thermal power station is a power
plant in which the prime mover is
steam driven. Water is heated, turns
into steam and spins a steam turbine
which drives an electrical generator.

53. SOLAR POWER PLANT
Solar power is the conversion of
sunlight into electricity, either directly
using photovoltaics (PV), or indirectly
using concentrated solar power
(CSP). Concentrated solar power
systems use lenses or mirrors and
tracking systems to focus a large area
of sunlight into a small beam.

54. ELECTRIC MOTOR
An electric motor is an
electrical machine that
converts electrical energy into
mechanical energy.

55. ELECTRIC GENERATOR
In electricity generation, a
generator is a device that
converts mechanical energy to
electrical energy for use in an
external circuit.