This document summarizes the history and development of electrical engineering from 1745 to the present. Some key events and developments include the first electrical capacitor in 1745, electric telegraph in 1837, electric oven in 1861, light bulb in 1874, alternating current network in 1887, diode in 1904, theory of semiconductors in 1929, programmable computer in 1943, transistor in 1947, microprocessor and microcomputer in 1971. It also discusses different electrical components like resistors, capacitors, diodes, transistors and relays as well as concepts like conduction, insulation, protection, control, energy transformation and more.

1. ELECTRICAL
ENGINEERING
Development till the Present
Chapter 14

2. 1745:
1ST
Electrical Capacitor

3. 1837:
1st
Electric Telegraph

4. 1861: 1st
Electric Oven
 WOOD
COMBINATION
ELECTRIC

5. 1874:
1st
Electric Light Bulb

6. 1887:
1ST
Alternating Current
Network

7. 1904 :
1st
Diode

8. 1929:
1ST
Theory of
Semi-Conductors

9. 1943:
1st
Programmable
Electronic Computer

10. 1947:
1st
Transistor
a semiconductor device is used to:
amplify
switch electronic signals
switch electrical power

11. 1971 : 1ST
Micro-Processor
& 1st
Micro-Computer

12. 1975: Pong console

13. 1977: Atari 2600 Console

14. 1978: Electronic QB
banned from high schools

15. 1980: 1st
Handheld Video
Games & Cell Phones

16. 1980s: 1st
Personal Computer

17. 1980s: The Walkman

18. 1998:
1st
Hard Drive MP3 Player

19. Electrical
Engineering
relates both electronics and
electricity

20. Electronic vs Electrical
 Electronic
 Made with
semiconductor material
 Usually silicon
 Examples
 Capacitors
 Diodes
 Transistors
 Relays
 Electrical
 Made with conductor
material
 Metals and alloys
 Examples
 Wires
 Switches
 Fuses

21. Alloy
 A homogeneous mixture made by
fusing two or more metals, or a metal
and a nonmetal.
 To obtain desirable qualities such as
hardness, lightness, and strength.
 Brass: Copper & Zinc
 Bronze:Copper & Tin

22. Electrical Current
 Electron flow current
occurs from the
negative terminal
(where there is an
excess of negative
electrons) to the
positive terminal
(where there is a lack of
electrons)
 Conventional current

23. Direct Current
 Electrons move continuously in the one
direction

24. Alternating
Current
 Electrons vibrate back and forth in a regular
pattern at 60 cycles per second or 60 Hz

25. Electrical function:
 the role that a component plays in the
control or transformation of electric current

26. Power Supply
 Provides the energy that causes
the current to flow through the
circuit

27. Advantages
Portable/Compact
Replaceable
Rechargeable
Cheap
Advantages
Continuous equal
flow
Recharges others
Good for big
items
Advantages
Renewable
Environment
friendly
Good for remote
places
Disadvantages
Drains fast
Limited Power
Polluting
Disadvantages
Stationary
Fire
Disadvantages
Expensive
Fragile
Good only when
sunny

28. Conduction
 Energy transfer from one material to
another by direct contact.
 Conductors are materials that allow
transfer to happen.
 E.g. copper, aluminum, silver and optical
fibres.
 A printed circuit is an electrical circuit
printed on a solid support called a circuit
board.

29. Insulation
 The electrical function performed
by a component to prevent the
flow of an electric current
 Prevent injury and short circuits
 E.g. Ceramic and plastic

30. Protection
 Protection is a component that
stops the flow of current in the
event of a power surge
 E.g. Fuses and circuit breakers

31. Control
 The function performed by a
component that can open or close a
circuit
 switches and pushbuttons are
examples of controls

32. Switches
 Rocker
 Toggle
 Push button
 Magnetic contact – Reed Switch
 Throw Switch

33. Throw Switches(love his voice)
 Single pole switches open/close 1
contact at a time
 Double pole switches open/close 2
contacts
 Single throw switches allow
electrons to follow 1 path.
 Double throw switches allow
electrons to follow 1 of 2 paths

34. Energy
Transformation
 Change of one form of energy (electricity)
to another form of energy
 Light energy
 Thermal (heat) energy
 Mechanical
 Sound
 Magnetic Induction

35. Components with
other Functions
 Capacitors
 Diodes
 Transistors
 Relays

36. Capacitors
 Can store electrical charge
 Composed of two electrical surfaces
separated by an insulator
 Charge builds up on one plate,
when the insulator is removed,
the charge is released
E.g. Camera flash

37. Diode
 Allows electric current to flow in one
direction
 Made of semi-conductors
 Protects electronic parts from
having electrons flow in the wrong
direction
 Used to convert AC to DC
 LEDs are Light Emitting Diodes

38. Transistors
 Block or amplify an
electric current
 Base acts like a valve that
controls current

39. Relays
 A relay opens or closes
a circuit using an
electrical signal from
another circuit
 Used in lighting in a
theatre, high voltage
appliances

40. Resistors
 Resistors limit the flow of electrons through an
electrical circuit
 E.g. A 10 Ω resistor has more conductance than
a 100 Ω resistor.

42. Coding on 4 band resistors:
 A resistor is banded with Red, Blue, Red, Gold;
 Thus the code gives 2, 6, 2, 5
 The 1st two bands gives the first two digits of
resistance; 2,6 = 26
 The 3rd band tells you the multiplier;
(2 102
=100)
 The last band is the tolerance (Gold= ±5%)
 26x 100 = 2600 Ω ±5% or 2600 ±5% 130 Ω
 Minimum R = 2570 Ω; Maximum R = 2730 Ω

43. Activity
 Page 479, Q. 1-15