Here are the steps to solve this problem: 1. Apply KVL around the loop containing V1, R1, and R2: V1 - I1R1 - I1R2 = 0 2. Apply Ohm's law at R1 and R2 to substitute for I1: V1 - (V1/R1)R1 - (V1/R1)R2 = 0 3. Simplify the equation: V1 - V1 - V1(R2/R1) = 0 4. Solve for V1: V1(1 + R2/R1) = 0 V1 = 0

2. 19EC1154
Basics of Electron
Devices and
Electric Circuits

4. SYLLABUS

5. UNIT I : ELECTRICAL
CIRCUITS AND ANALYSIS
Ohm‘s law, DC and AC circuits
fundamentals, Kirchhoff‘s laws, Mesh
and Nodal analysis-Theorems and
simple problems: Superposition,
Maximum power transfer theorem -
Experimental study -Verification
of superposition theorem.

6. UNIT II : CIRCUIT
TRANSIENTS AND
RESONANCES
Basic RL, RC and RLC circuits and
their responses to DC and sinusoidal
inputs –frequency response – Parallel
and series resonances – Q factor.
Experimental verification of series
resonance. Experimental study-
Determination of Resonance
Frequency of Series RLC Circuits

7. UNIT III : DIODE AND
TRANSISTOR
Characteristics of PN Junction Diode –
Zener Diode and its Characteristics –
Zener Effect– Zener Voltage
Regulator.Bipolar Junction Transistor
(BJT) Construction – CB, CE, CC
Configurations and Characteristics-
Experimental study-PN Junction
Diode Characteristics,Zener Diode
Characteristics

8. UNIT IV : SPECIAL
SEMICONDUCTOR DEVICES
Construction, Characteristics and
Applications of FET - UJT – SCR,
Photo diode, Photo Transistor -
LED and LCD- Implementation of
Photo diode application.
Experimental study- FET
Characteristics

9. UNIT V : BASICS OF POWER
SUPPLY AND ELECTRICAL
WIRING
Introduction to Power supply circuits:
Half wave, Full wave Rectifier –SMPS -
UPS (online & offline).Cable and wire
types and applications – Two way and
three way control- Experimental
study - Implementation of simple
wiring circuit for a Computer
network

11. SYMBOL OF VOLTAGE

12. VOLTAGE
 Voltage, also called electromotive force, is a quantitative expression
of the potential difference in charge between two points in an
electrical field.
 The greater the voltage, the greater the flow of electrical current (that
is, the quantity of charge carriers that pass a fixed point per unit of
time) through a conducting or semiconducting medium for a given
resistance to the flow.
 Voltage is symbolized by an uppercase italic letter V or E. The
standard unit is the volt, symbolized by a non-italic uppercase letter
V.
 One volt will drive one coulomb (6.24 x 1018) charge carriers, such
as electrons, through a resistance of one ohm in one second.

13. TYPE THE STANDARD VALUE OF
VOLTAGE FOR SINGLE PHASE AC
SUPPLY WE ARE GETTING FOR OUR
HOME FROM ELECTRICITY BOARD IN
CHAT BOX NOW
?????

15. SYMBOL OF CURRENT

16. CURRENT
 The electric current is the rate of flow of electric charge through a
conducting medium with respect to time.
 When there is a potential difference between two points in a conductive
medium, electric charge starts flowing from the higher potential point to
the lower potential point to balance the charge distribution between the
points.
 The rate of flow of charge in respect of time is known as electric
current.
 If q Coulomb electric charge gets transferred between these two points in
time t sec, then the current can be calculated as
q/t

17. RESISTANCE

18. RESISTANCE
 Resistance (also known as ohmic resistance or electrical
resistance) is a measure of the opposition to current flow in an
electrical circuit. Resistance is measured in ohms, symbolized
by the Greek letter omega (Ω).
 When a voltage is applied across a substance there will be
an electric current through it.
 The applied voltage across the substance is directly
proportional to the current through it.
 The constant of proportionality is resistance. Hence resistance
is defined as the ratio of the applied voltage to the current
through the substance.Where V is voltage, I is current and R is
resistance.

19. SYMBOL OF RESISTANCE

20. FOR BETTER UNDERSTANDING…

21. STILL U CAN’T..? LOOK THIS…

22. AC WAVEFORM

23. DC WAVEFORM

24. OHM’S LAW
 The first, and perhaps most important, the relationship between
current, voltage, and resistance is called Ohm’s Law, discovered by
Georg Simon Ohm and published in his 1827 paper.
 Ohm’s law states that the voltage across a conductor is directly
proportional to the current flowing through it, provided all physical
conditions and temperature remain constant.

25. PROBLEM-1
 Determine the current resulting from the application of a
9-V battery across a network with a resistance of 2.2 .

26. PROBLEM-2
Calculate the resistance of a 60-W bulb if a current of 500
mA results from an applied voltage of 120 V.

27. PROBLEM-3
Calculate the current through the 2-k resistor of Fig. if the
voltage drop across it is 16 V.

28. PROBLEM-4 (DO IT BY YOURSELF)
 Calculate the voltage that must be applied across the
soldering iron of Fig. to establish a current of 1.5 A
through the iron if its internal resistance is 80 .

29. Any doubts????

30. The limitations of Ohm’s law
 This law cannot be applied to unilateral networks.
A unilateral network has unilateral elements
like diode transistors, etc., which do not have
same voltage current relation for both directions of
current.
 Ohm’s law is also not applicable for non – linear
elements. Non-linear elements are those which do not
have current exactly proportional to the applied voltage,
that means the resistance value of those elements
changes for different values of voltage and current.
Examples of non – linear elements are thyristor, electric
arc, etc.

31. KIRCHHOFF’S VOLTAGE LAW
 For any closed path in a network, Kirchhoff’s voltage law
(KVL) states that the algebraic sum of the voltages is
zero.
 Some of the voltages will be sources, while others will
result from current in passive elements creating a
voltage, which is sometimes referred to as a voltage
drop.

32. EXAMPLE

33. CIRCUIT

34. PROBLEM 5

35. SOLUTION

36. KIRCHHOFF’S CURRENT LAW
 The connection of two or more circuit elements creates a
junction called a node.
 The junction between two elements is called a simple
node and no division of current results.
 The junction of three or more elements is called a
principal node, and here current division does take
place.
 Kirchhoff’s current law (KCL) states that the algebraic
sum of the currents at a node is zero.

37. PROBLEM 6

38. PROBLEM 7

40. Determine the current flowing
through this circuit

46. IMPORTANT FORMULAS
 V=IR
 AC POWER = VIcosф
 DC POWER = VI or IR*I

47. PROBLEM-10
For the circuit in Fig. 2.21(a), find voltages v1 and v2.

49. Problem-11 (class work out)
Find V1 and V2 in the circuit.