1.1 UNIT-1: SYLLABUS
Introduction to Resistors, Capacitors, Inductors and Transformers, Concept of ideal dc voltage and
current source, KVL, KCL, Thevenin’s, Norton’s, maximum power transfer, Millman’s theorem
(statement, proof, simple numerical application for dc only).
1.2 INTRODUCTION TO RESISTOR
A resistor is a passive component which opposes to the flow of electric current through it. Thus the
property by the virtue of which opposes to the flow of electric current is called as its resistance. This
opposition is measured in terms of Ohm (Ω). For larger values of resistance, kΩ, MΩ units are also
used. The value of carbon resistor is identified using the color rings printed on its body.
1.2.1 Law of resistor
The resistance offered by the conductor depends on following factors:
1. It is directly proportional to the length (l) of conductor
2. It is inversely proportional to the area of cross section (a) of conductor
(l)
th
ng
3. Coefficient of resistivity i.e. nature of the conductor material ( )
le
4. Thus mathematically the resistance of a conductor is given by: area (a)
= . Ω
1.2.2 Color Code Chart of Resistors
The body of the resistor is printed with color rings as shown below. With the help of these color rings
(first band, second band and multiplier band) we can find the value of the resistor using following
color code chart. The forth band is known as multiplier band. It gives us the tolerance value of the
resistor.
1st 2nd 1st 2nd
Color Multiplier Color Multiplier
Band Band Band Band
Black - 0 X 10 Blue 6 6 X 10
0 6
Brown 1 1 X 10
1
Violet 7 7 Never
found on
Red 2 2 X 10 Grey 8 8
2
3rd
Orange 3 3 X 10 White 9 9 position
3
Yellow 4 4 X 10 Golden - - X 10
4 -1
Green 5 5 X 10 Silver - - X 10
5 -2
Tolerance band values: Golden = ±5%, Silver = ±10% and other color = ±20%
Simple Notes of B.Sc. Electronics Sem I & II, www.vsagar.org
,EXERCISE
Ques 1: Calculate the values of resistors from the following colour codes:
7. Blue Grey Golden, Golden –
1. Green Blue Yellow, Golden –
8. Red Red Golden, Silver –
2. Orange Orange Brown, Golden –
9. Yellow Violet Black, Silver –
3. Yellow Violet Black, Golden –
10. Brown Black Golden, Golden –
4. Brown Green Golden, Golden –
11. Orange orange Green, Golden –
5. Red Red Green, Silver –
6. Orange Orange Orange, Silver –
12. Grey Red Green, Silver –
Ques 2: Write down the three color bands for the following resistor values with ±5% and 10%:
5) 10k, 12k, 15k, 18k, 22k, 33k,
1) 1, 2, 2.2, 3.3, 4.7, 5, 6.8, 8.2
47k, 56k, 68k, 82k
2) 10, 12, 15, 18, 22, 33, 47, 56,
6) 100k, 120k, 150k, 180k, 220k,
68, 82
330k, 470k, 560k, 680k, 820k
3) 100, 120, 150, 180, 220, 330,
7) 1M, 1.2M, 1.5M, 2.2M, 3.3M,
470, 560, 680, 820
4.7M , 5M, 10M
4) 1k, 2k, 2.2k, 3.3k, 4.7k, 5k,
6.8k, 8.2k
1.3 TYPES OF FIXED RESISTORS
Resistor is used in the circuit to limit the electric current. It is also used to produce voltage drop in a
circuit. Basically there are following types of resistors –
1) Fixed resistor type
a) Wire wound resistor
b) Carbon composition resistor
c) Carbon film resistor
d) Film type resistor
2) Variable resistor types
a) Rheostat
b) Potentiometer
1.3.1 Wire wound resistor
This type of resistor is used in heavy current and high power applications. It has very stable value of
resistance. It is made up of special resistive wire like
Nichrome or Mangenin wound on a round insulating core
made up of Asbestos, Ceramic or China clay type hollow
cylinder. Their values range 0.01 to 100k with a power
rating from watts (W) to kilowatts (kW).
The value of the resistor is calculated using the formula:
= . Ω
However it is not available in higher value of resistance. Due to such high power rating its size is very
large.
Simple Notes of B.Sc. Electronics Sem I & II, www.vsagar.org
,1.3.2 Carbon composition resistor
This type of resistor is widely used in electronic circuit. They are available in different values from 1
to 20M with a typical power rating from 1/8W to 2W. These resistors are low cost and they have
small size.
They are made up of finely divided carbon mixed with powdered insulating material in suitable
proportion. The resistive element is simple rod of pressed carbon granules which are usually enclosed
in a plastic case or insulation for good mechanical strength, as shown in following diagram.
solid resistance material
terminal terminal
color codes metal cap
The two terminals of carbon resistor element are joined to metal caps with lead of wires for soldering
connections in the circuit.
1.4 RESISTORS IN PARALLEL & SERIES
Resistors in parallel: When a number of resistors are in parallel, the reciprocal of total resistance of the
circuit is equal to the addition of reciprocals of each resistance.
Resistors in series: When a number of resistors are in series, the total resistance of the circuit is equal to
the addition of all resistances.
R2 R1
R4 R3 R2 R1 R R3 R
R4
Resistors in parallel Resistors in series
= + + + = + + +
1.5 CAPACITORS
Capacitor is an electrical device which consists of two parallel metal plates separated by an insulator
known as dielectric. It is used to store electric charge in the form of potential difference or voltage.
Its capacity to store electric charge is called as its capacitance. The capacity of capacitor is also given
by the equation, as follows:
Where, C = capacity of capacitor in Farad
. . 2
= A = are of two plates in m
d = distance between two plates in meter
0 = relative permittivity of dielectric medium
= absolute permittivity of free space or vacuum
Simple Notes of B.Sc. Electronics Sem I & II, www.vsagar.org
, The constructional diagram of a parallel plate capacitor is given below:
1.5.1 Classification of capacitors
Following diagram shows the classification of different types of capacitors:
Classification of
Capacitors
Electrolytic Non electrolytic Variable
(Polar) (Non-polar) Capacitors
Alluminium Tantalum Paper Ceramic Polyester
Mica Capacitors
Capacitors Capacitors Capacitors Capacitors Capacitors
1.5.2 Electrolytic capacitors
This capacitor is called as electrolytic because it uses electrolyte as borax or carbon salt as a negative
plate. A thin strip of Aluminium is coated with a molecular thin film of
aluminium oxide by electrochemical process.
It is covered with a layer of gauze socked in electrolyte or borax. On its
top another metal plate in contact with electrolyte is placed. This is the
second plate of capacitor. Then the two plates are rolled up into a
compact cylinder and placed inside a metal cylinder. This enclosing
cylinder creates contact with the outer metal foil of capacitor and acts as
negative terminal. Finally the metal cylinder is enclosed in a paper tube in
order to avoid electric shock, because of extremely thin dielectric film. These types of capacitors are
available in large values.
negative
terminal
metal plate
dielectric
medium gauze
saturation
oxide
film
positive
terminal
Simple Notes of B.Sc. Electronics Sem I & II, www.vsagar.org
Introduction to Resistors, Capacitors, Inductors and Transformers, Concept of ideal dc voltage and
current source, KVL, KCL, Thevenin’s, Norton’s, maximum power transfer, Millman’s theorem
(statement, proof, simple numerical application for dc only).
1.2 INTRODUCTION TO RESISTOR
A resistor is a passive component which opposes to the flow of electric current through it. Thus the
property by the virtue of which opposes to the flow of electric current is called as its resistance. This
opposition is measured in terms of Ohm (Ω). For larger values of resistance, kΩ, MΩ units are also
used. The value of carbon resistor is identified using the color rings printed on its body.
1.2.1 Law of resistor
The resistance offered by the conductor depends on following factors:
1. It is directly proportional to the length (l) of conductor
2. It is inversely proportional to the area of cross section (a) of conductor
(l)
th
ng
3. Coefficient of resistivity i.e. nature of the conductor material ( )
le
4. Thus mathematically the resistance of a conductor is given by: area (a)
= . Ω
1.2.2 Color Code Chart of Resistors
The body of the resistor is printed with color rings as shown below. With the help of these color rings
(first band, second band and multiplier band) we can find the value of the resistor using following
color code chart. The forth band is known as multiplier band. It gives us the tolerance value of the
resistor.
1st 2nd 1st 2nd
Color Multiplier Color Multiplier
Band Band Band Band
Black - 0 X 10 Blue 6 6 X 10
0 6
Brown 1 1 X 10
1
Violet 7 7 Never
found on
Red 2 2 X 10 Grey 8 8
2
3rd
Orange 3 3 X 10 White 9 9 position
3
Yellow 4 4 X 10 Golden - - X 10
4 -1
Green 5 5 X 10 Silver - - X 10
5 -2
Tolerance band values: Golden = ±5%, Silver = ±10% and other color = ±20%
Simple Notes of B.Sc. Electronics Sem I & II, www.vsagar.org
,EXERCISE
Ques 1: Calculate the values of resistors from the following colour codes:
7. Blue Grey Golden, Golden –
1. Green Blue Yellow, Golden –
8. Red Red Golden, Silver –
2. Orange Orange Brown, Golden –
9. Yellow Violet Black, Silver –
3. Yellow Violet Black, Golden –
10. Brown Black Golden, Golden –
4. Brown Green Golden, Golden –
11. Orange orange Green, Golden –
5. Red Red Green, Silver –
6. Orange Orange Orange, Silver –
12. Grey Red Green, Silver –
Ques 2: Write down the three color bands for the following resistor values with ±5% and 10%:
5) 10k, 12k, 15k, 18k, 22k, 33k,
1) 1, 2, 2.2, 3.3, 4.7, 5, 6.8, 8.2
47k, 56k, 68k, 82k
2) 10, 12, 15, 18, 22, 33, 47, 56,
6) 100k, 120k, 150k, 180k, 220k,
68, 82
330k, 470k, 560k, 680k, 820k
3) 100, 120, 150, 180, 220, 330,
7) 1M, 1.2M, 1.5M, 2.2M, 3.3M,
470, 560, 680, 820
4.7M , 5M, 10M
4) 1k, 2k, 2.2k, 3.3k, 4.7k, 5k,
6.8k, 8.2k
1.3 TYPES OF FIXED RESISTORS
Resistor is used in the circuit to limit the electric current. It is also used to produce voltage drop in a
circuit. Basically there are following types of resistors –
1) Fixed resistor type
a) Wire wound resistor
b) Carbon composition resistor
c) Carbon film resistor
d) Film type resistor
2) Variable resistor types
a) Rheostat
b) Potentiometer
1.3.1 Wire wound resistor
This type of resistor is used in heavy current and high power applications. It has very stable value of
resistance. It is made up of special resistive wire like
Nichrome or Mangenin wound on a round insulating core
made up of Asbestos, Ceramic or China clay type hollow
cylinder. Their values range 0.01 to 100k with a power
rating from watts (W) to kilowatts (kW).
The value of the resistor is calculated using the formula:
= . Ω
However it is not available in higher value of resistance. Due to such high power rating its size is very
large.
Simple Notes of B.Sc. Electronics Sem I & II, www.vsagar.org
,1.3.2 Carbon composition resistor
This type of resistor is widely used in electronic circuit. They are available in different values from 1
to 20M with a typical power rating from 1/8W to 2W. These resistors are low cost and they have
small size.
They are made up of finely divided carbon mixed with powdered insulating material in suitable
proportion. The resistive element is simple rod of pressed carbon granules which are usually enclosed
in a plastic case or insulation for good mechanical strength, as shown in following diagram.
solid resistance material
terminal terminal
color codes metal cap
The two terminals of carbon resistor element are joined to metal caps with lead of wires for soldering
connections in the circuit.
1.4 RESISTORS IN PARALLEL & SERIES
Resistors in parallel: When a number of resistors are in parallel, the reciprocal of total resistance of the
circuit is equal to the addition of reciprocals of each resistance.
Resistors in series: When a number of resistors are in series, the total resistance of the circuit is equal to
the addition of all resistances.
R2 R1
R4 R3 R2 R1 R R3 R
R4
Resistors in parallel Resistors in series
= + + + = + + +
1.5 CAPACITORS
Capacitor is an electrical device which consists of two parallel metal plates separated by an insulator
known as dielectric. It is used to store electric charge in the form of potential difference or voltage.
Its capacity to store electric charge is called as its capacitance. The capacity of capacitor is also given
by the equation, as follows:
Where, C = capacity of capacitor in Farad
. . 2
= A = are of two plates in m
d = distance between two plates in meter
0 = relative permittivity of dielectric medium
= absolute permittivity of free space or vacuum
Simple Notes of B.Sc. Electronics Sem I & II, www.vsagar.org
, The constructional diagram of a parallel plate capacitor is given below:
1.5.1 Classification of capacitors
Following diagram shows the classification of different types of capacitors:
Classification of
Capacitors
Electrolytic Non electrolytic Variable
(Polar) (Non-polar) Capacitors
Alluminium Tantalum Paper Ceramic Polyester
Mica Capacitors
Capacitors Capacitors Capacitors Capacitors Capacitors
1.5.2 Electrolytic capacitors
This capacitor is called as electrolytic because it uses electrolyte as borax or carbon salt as a negative
plate. A thin strip of Aluminium is coated with a molecular thin film of
aluminium oxide by electrochemical process.
It is covered with a layer of gauze socked in electrolyte or borax. On its
top another metal plate in contact with electrolyte is placed. This is the
second plate of capacitor. Then the two plates are rolled up into a
compact cylinder and placed inside a metal cylinder. This enclosing
cylinder creates contact with the outer metal foil of capacitor and acts as
negative terminal. Finally the metal cylinder is enclosed in a paper tube in
order to avoid electric shock, because of extremely thin dielectric film. These types of capacitors are
available in large values.
negative
terminal
metal plate
dielectric
medium gauze
saturation
oxide
film
positive
terminal
Simple Notes of B.Sc. Electronics Sem I & II, www.vsagar.org
