about bonding of covalent structures

1. Lecture1
BASIC ELECTRONICS

2. Lecture topics
 Introduction
 Motivation and application of electronics in CS
 Voltage
 Current
 Resistance

3. Text BooK
 Principles of Electric Circuits
(Conventional Current Version)
 By Thomas L. Floyd
 9th Edition

4. Reference BooK
 Electronic devices
 By Thomas L. Floyd
 9th Edition

5. Misconception
 We are students of Computer Science
 Why do we need to study Electronics?
 This is just a subject for Electrical Engineering students.

6. Why do we need electronics in
the field of cs?
 Computing and Electronics go side by side
 The study of both subjects together holds huge advantages
 Development of electronics has led to the development of real time
Computing Experience

7. Why do we need electronics in
the field of cs?
 Knowledge and practical abilities spanning both disciplines
 You never know when you will have to make a program that uses a
concept from electronics or uses an analogy of how circuits work

8. Open your Options !
 The study of Computing technologies equip you with both the theoretical
and practical abilities to approach problems or challenges in hardware or
software, whilst the Electronics side allows you to transfer your ideas to a
tangible design.
 Grab the opportunity to understand basic electronics in detail for future
perspectives

9. Electronics Kit (mandatory)
 Buy your Electronics Kit from UCP Bookshop
 Before Second Week

10. Current
1. Is there any flow in static water? No
2. Similarly, no current in static electrons
flow of water == flow electrons == current
3. As electrons move in same direction, there is current.

11.  As current is the movement of charged particles through load….so does
this movement take place on it own?
 NO
 The force required is voltage.
 Without force : motion is random
and I=0

12. How does Electric Current Flow?

13.  Voltage is the pressure inserted by the water in upper tank.
 Just like the battery is inserting pressure on the current to
flow through wire.

14. Imp points of I and formula/unit
 the current must be the same at all points of the wire at any time.
 The symbol for current is I
 I is rate of flow of electric charge past a point or region
 Formula : I = Q /t unit: Ampere (A)
 Direction of current: form positive to negative terminal for conventional
current

15. Electric circuit
 Electric current doesn’t flow just anywhere. Electrons only flow if you
provide a closed conductive path, known as an electrical circuit, or simply
a circuit, for them to move

16. Important points
 A voltage is simply a difference in electrical charge between two points.
 The force that compels current to flow when the circuit is completed is
created by the difference between charges at the battery terminals.
 (if the amount of water is not different at two place====there is no flow)

17. Electrical Energy sources
 But where does the original energy — the thing that starts the electrons —
come from? It comes from a source
 Two sources: AC and DC.
 Sources are: battery, generators, solar cells etc

18. Imp points
 Voltage = W/Q
 Work needed per unit of charge to move a test charge between the two
points
 Unit = 1volt (V) =1J /1C
 Voltage is taken between two points (not at one point)
 Energy released when a unit moves downhill from
higher potential to lower potential.

19. Voltage
voltage current
Generate by doing work on charges in
devices (batteries, soalr cells, genertaors
etc)
Get by placing voltage across things (bulb,
resitsor)
Voltage can exist without current current cannot exist without
voltage.
voltage source has polarity current has a direction.

20. Why are we calling it Low and High Current here?

21. Resistance
 Analogy1 :
 Mechanical system friction ==electrical system resistance
(puts brakes on current flow)
 Analogy 2:

22. Important Pints of resistance
 Resistance:
 It is a measure of the opposition to current flow in an electrical circuit
 Resistance :
1. generate heat and light,
2. restrict the flow of electric
3. ensure that the correct voltage is supplied to device
 The higher the resistance, the more restricted the flow of current.

23.  What happen to the brightness of bulb you put resistor in circuit?
 Why we need resistor in circuit?
 Ans: to limit current value

24.  Why conducting wires having current do not heat up
 ans: because of resistance in them
 Why diff voltages to be applied in both circuit having same current.
 Ans: because of different resistances