assignment no · in accordance with ohm's law: v = ir . the resistance r is equals to the...
TRANSCRIPT
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 1
OBJECTIVE:
1. Study of passive components -
Resistors, Capacitors, Inductors and transformers
2. To Identify and understand different types of connectors, switches.
THEORY:
There are two types of components that we come across in electronics namely Active
and Passive components. Resistors, Capacitors etc., are known as passive components
because they can only attenuate the electrical voltage and signals and cannot amplify
Whereas active devices like transistors, operational amplifier (Op Amp) can amplify or
increase the amplitude and energy associated with the signals.
Passive components
Resistors Capacitors Inductors
RESISTORS
A resistor is a two-terminal electronic component designed to oppose an electric current
by producing a voltage drop between its terminals in proportion to the current, that is,
in accordance with Ohm's law: V = IR. The resistance R is equals to the voltage drop V
across the resistor divided by the current I through the resistor.
The primary characteristics of resistors are their resistance and the power they can
dissipate. Other characteristics include temperature coefficient, noise, and inductance.
Practical resistors can be made of resistive wire and various compounds and films, and
they can be integrated into hybrid and printed circuits. Size and position of leads are
relevant to equipment designers; resistors must be physically large enough not to
overheat when dissipating their power. Resistors can be broadly of two types Fixed
Resistors and Variable Resistors.
ASSIGNMENT NO.1
TITLE: STUDY OF DIFFERENT ELECTRONIC COMPONENTS
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International Institute of Information Technology, Hinjawadi, Pune. Page 2
The symbols are as shown below
Fixed Resistors:
Carbon Film (5%, 10% tolerance) and Metal Film Resistors (1%,2% tolerances) and wire
wound resistors. A fixed resistor is one for which the value of its resistance is specified
and cannot be varied in general.
Resistance Value:
The resistance value is displayed using the color code (the colored bars/the colored
stripes), because the average resistor is too small to have the value printed on it with
numbers. The resistance value is a discrete value. For example, the values [1], [2.2], [4.7]
and [10] are used in a typical situation.
Colour coding:
Example 1:
(Brown=1), (Black=0), (Orange=3)
10 x 103 = 10k ohm; Tolerance (Gold) = ±5%
Fig. 1.1: Resistor
Table 1.1: Color band chart for calculating the value of resistor
Color Value Multiplier Tolerence(%)
Black 0 1 -
Brown 1 101 ±1
Red 2 102 ±2
Orange 3 103 ±0.05
Yellow 4 104 -
Green 5 105 ±0.5
Blue 6 106 ±0.25
Violet 7 107 ±0.1
Gray 8 108 -
White 9 109 -
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Gold - 10-1 ±5
Silver - 10-2 ±10
None - - ±20
Variable Resistors:
Variable resistors are adjustable by changing the position of a tapping on the resistive
element and resistors with a movable tap ("potentiometers"), either adjustable by the
user of equipment or contained within, are also used.
Resistors are used as part of electrical networks and electronic circuits. There are special
types of resistor whose resistance varies with various quantities, most of which have
names, and articles, of their own the resistance of thermistor varies greatly with
temperature, whether external or due to dissipation, so they can be used for
temperature or current sensing metal oxide varistors drop to a very low resistance
when a high voltage is applied, making them suitable for over-voltage protection the
resistance of a strain gauge varies with mechanical load; the resistance of photoresistors
varies with illumination; the resistance of a Quantum Tunnelling Composite can vary
by a factor of 1012 with mechanical pressure applied and so on.
Units:
The ohm (symbol: Ω) is a SI-driven unit of electrical resistance, named after Georg Ohm.
Letter R is used for Ohms, ‘K’ for Kilohms and ‘M’ for Megaohms and placed where the
decimal point would go.
Examples
R47 0.47 ohms
4R7 4.7 ohms
470R 470 Ohms
4K7 4.7K ohms
47K 47K ohms
47K3 47.3K ohms
470K 470K ohms
Carbon Film Resistors:
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International Institute of Information Technology, Hinjawadi, Pune. Page 4
This is the most general purpose, cheap resistor. Usually the tolerance of the resistance
value is ±5%. Power ratings of 1/8W, 1/4W and 1/2W are frequently used. The
disadvantage of using carbon film resistors is that they tend to be electrically noisy.
Fig.1.2:Carbon film resistor (CFR)
Metal film Resistors:
Metal film resistors are used when a higher tolerance (more accurate value) is needed.
Nichrome (Ni-Cr) is generally used for the material of resistor. They are much more
accurate in value than carbon film resistors. They have about ±0.05% tolerance.
Fig.1.3:Metal film resistor (MFR)
Ceramic Resistors:
Another type of resistor is the Ceramic resistor. These are wire wound resistors in a
ceramic case, strengthened with special cement. They have very high power ratings,
from 1 or 2 watts to dozens of watts. These resistors can become extremely hot when
used for high power applications, and this must be taken into account when designing
the circuit.
Fig.1.4: Ceramic resistor
Single Line Network resistor:
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Fig.1.5: Single line network resistor
Wire Wound Resistors:
There is another type of resistor called the wire wound resistor. A wire wound resistor
is made of metal resistance wire, and because of this, they can be manufactured to
precise values. Also, high-wattage resistors can be made by using a thick wire material.
Wire wound resistors cannot be used for high-frequency circuits.
Fig.1.6: Wire wound resistor
Variable Resistors:
There are two general ways in which variable resistors are used. One is the variable
resistor whose value is easily changed, like the volume adjustment of Radio. The other
is semi-fixed resistor that is not meant to be adjusted by anyone but a technician. It is
used to adjust the operating condition of the circuit by the technician.
Semi-fixed resistors are used to compensate for the inaccuracies of the resistors, and to
fine-tune a circuit. The rotation angle of the variable resistor is usually about 300
degrees. Some variable resistors must be turned many times ( multi-turn Pot) to use the
whole range of resistance they offer. This allows for very precise adjustments of their
value. These are called "Potentiometers" or "Trimmer Potentiometers” or “presets”.
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Fig.1.7: Variable resistors
Light Dependent Resistors:
One type of variable resistor is the Cadmium Sulphide Photocell. It is a kind of resistor,
whose value depends on the amount of light falling on it. When in darkness its
resistance if very large and as more and more light falls on it its resistance becomes
smaller and smaller.
Fig.1.8: Light dependent resistor
Thermistors:
The resistance value of the thermistor changes according to temperature. They are used
as a temperature sensor. There are generally two types of thermistors with
• Negative Temperature Coefficient (NTC)
• Positive Temperature Coefficient (PTC)
•
Fig.1.9: Thermistor
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CAPACITOR
Capacitor consists of two or more parallel conductive (metal) plates which are not
connected or touching each other, but are electrically separated either by air or by some
form of insulating material such as paper, mica, ceramic or plastic and which is
commonly called the capacitors Dielectric.
Fig.1.10: Working of capacitor
Dielectric Capacitors are usually of the variable type where a continuous variation of
capacitance is required for tuning transmitters, receivers and transistor radios. The
position of the moving plates with respect to the fixed plates determines the overall
capacitance value. The capacitance is generally at maximum when the two sets of plates
are fully meshed together. High voltage type tuning capacitors have relatively large
spacings or air-gaps between the plates with breakdown voltages reaching many
thousands of volts.
Variable Capacitors symbol:
Fig.1.11: Trimmer capacitor
As well as the continuously variable types, preset type variable capacitors are also
available called Trimmers. These are generally small devices that can be adjusted or
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"pre-set" to a particular capacitance value with the aid of a small screwdriver and are
available in very small capacitances of 500pF or less and are non-polarized.
Ceramic Capacitors:
Ceramic Capacitors or Disc Capacitors are made by coating two sides of a small
ceramic disc with silver and are then stacked together to make a capacitor. For very low
capacitance values a single ceramic disc of about 3-6mm is used. Ceramic capacitors
have a high dielectric constant (High-K) and are available so that relatively high
capacitances can be obtained in a small physical size.
Fig. 1.12: Ceramic capacitor
They exhibit large non-linear changes in capacitance against temperature and as a result
are used as de-coupling or by-pass capacitors as they are also non-polarized devices.
Ceramic capacitors have values ranging from a few Picofarads to one or two
microfarads but their voltage ratings are generally quite low.
Ceramic types of capacitors generally have a 3-digit code printed onto their body to
identify their capacitance value in picofarads. Generally the first two digits indicate the
capacitors value and the third digit indicates the number of zero's to be added. For
example, a ceramic disc capacitor with the markings 103 would indicate 10 and 3 zero's
in pico-farads which is equivalent to 10,000 pF or 10nF. Letter codes are sometimes used
to indicate their tolerance value such as: J = 5%, K = 10% or M = 20% etc.
ELECTROLYTIC CAPACITORS
Electrolytic Capacitors are generally used when very large capacitance values are
required. This insulating layer is so thin that it is possible to make capacitors with a
large value of capacitance for a small physical size as the distance between the plates, d
is very small.
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Fig. 1.13: Electrolytic Capacitor
The majority of electrolytic types of capacitors are Polarized, that is the DC voltage
applied to the capacitor terminals must be of the correct polarity, i.e. positive to the
positive terminal and negative to the negative terminal as an incorrect polarization will
break down the insulating oxide layer and permanent damage may result. All polarized
electrolytic capacitors have their polarity clearly marked with a negative sign to indicate
the negative terminal and this polarity must be followed. Electrolytic Capacitors are
generally used in DC power supply circuits due to their large capacitances and small
size to help reduce the ripple voltage or for coupling and decoupling applications. One
main disadvantage of electrolytic capacitors is their relatively low voltage rating and
due to the polarization of electrolytic capacitors. Electrolytic generally come in two
basic forms; Aluminum Electrolytic Capacitors and Tantalum Electrolytic Capacitors.
CAPACITOR CHARACTERISTICS
Fig.1.14: Capacitor characteristics
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CAPACITOR COLOUR CODE TABLE:
Table 1.2 Capacitor color code table
Colour Digit
A
Digit
B
Multiplier
D
Tolerance
(T) > 10pf
Tolerance
(T) < 10pf
Temperature
Coefficient
(TC)
Black 0 0 x1 ± 20% ± 2.0pF
Brown 1 1 x10 ± 1% ± 0.1pF -33x10-6
Red 2 2 x100 ± 2% ± 0.25pF -75x10-6
Orange 3 3 x1,000 ± 3% -150x10-6
Yellow 4 4 x10,000 ± 4% -220x10-6
Green 5 5 x100,000 ± 5% ± 0.5pF -330x10-6
Blue 6 6 x1,000,000 -470x10-6
Violet 7 7 -750x10-6
Grey 8 8 x0.01 +80%,-
20%
White 9 9 x0.1 ± 10% ± 1.0pF
Gold x0.1 ± 5%
Silver x0.01 ± 10%
CAPACITOR VOLTAGE COLOUR CODE TABLE:
Table 1.3 Capacitor voltage color code table
Colour Voltage Rating (V)
Type J Type K Type L Type M Type N
Black 4 100 10 10
Brown 6 200 100 1.6
Red 10 300 250 4 35
Orange 15 400 40
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Yellow 20 500 400 6.3 6
Green 25 600 16 15
Blue 35 700 630 20
Violet 50 800
Grey 900 25 25
White 3 1000 2.5 3
Gold 2000
Silver
Capacitor Voltage Reference
• Type J : Dipped Tantalum Capacitors.
• Type K : Mica Capacitors.
• Type L : Polyester/Polystyrene Capacitors.
• Type M : Electrolytic 4 Band Capacitors.
• Type N : Electrolytic 3 Band Capacitors.
Metalized Polyester Capacitor
Disc & Ceramic Capacitor
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Fig. 1.15: capacitor value identification
Capacitor Tolerance Letter Codes Table
Table1.4: Capacitor tolerance letter code table
Letter B C D F G J K M Z
Tolerance C <10pF ±pF 0.1 0.25 0.5 1 2
C >10pF ±% 0.5 1 2 5 10 20 +80-20
Consider the capacitor below:
The capacitor on the left is of a ceramic disc type capacitor
that has the code 473J printed onto its body. Then the 4 = 1st
digit, the 7 = 2nd digit,
the 3 is the multiplier in pico-Farads, pF and the letter J is the
tolerance and this translates to:
47pF * 1,000 (3 zero's) = 47,000 pF , 47nF or 0.047 uF
the J indicates a tolerance of +/- 5%
Fig. 1.16: capacitor code
Mica Capacitors:
These capacitors use Mica for the dielectric. Mica capacitors have good stability because
their temperature coefficient is small. Because their frequency characteristic is excellent,
they are used for resonance circuits, and high frequency filters. They have very good
insulation, and so can be utilized in high voltage circuits. It was often used for vacuum
tube style radio transmitters, etc. Mica capacitors do not have high values of
capacitance, and they can be relatively expensive. Pictures shown are "Dipped mica
capacitors.” These can handle upto 500 volts. These capacitors have no polarity.
Fig.1.17: mica capacitor
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Variable capacitors:
Variable capacitors are used for adjustment of frequency mainly. The value of the
capacitor can be affected by the capacitance of the screwdriver we use so we have to use
a special screwdriver.
There are different colors, as well. Blue: 7pF (2 -9), white: 10pF (3 -15), green: 30pF (5 -
35), brown: 60pF (8 -72). These capacitors are used for radio tuners. The capacitance is
varied by turning the spindle which changes the area between the plates.
Fig.1.18: variable capacitors
APPLICATIONS:
1) Energy storage
2) Pulsed power and weapons
3) Power conditioning
4) Power factor correction
5) Supression and coupling
6) Noise filters and snubbers
7) Motor starters
8) Signal processing
9) Tuned circuits
INDUCTORS:
Fig.1.19: Types of inductor
An inductor is a passive electrical component that can store energy in a magnetic field
created by the electric current passing through it. An inductor's ability to store magnetic
energy is measured by its inductance, in units of Henries.
APPLICATIONS:
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1) Inductors are used extensively in analog circuits and signal processing.
2) An inductor is used as the energy storage device in some switched-mode power
supplies.
3) Inductors are also employed in electrical transmission systems, where they are used
to depress voltages from lightning strikes and to limit switching currents and fault
current. In this field, they are more commonly referred to as reactors.
Fig.1.20: simple transformer
A transformer is a device that transfers electrical energy from one circuit to another
through inductively coupled electrical conductors. A changing current in the first circuit
(the primary) creates a changing magnetic field. This changing magnetic field induces a
changing voltage in the second circuit (the secondary). This effect is called mutual
induction.
If a load is connected to the secondary circuit, electric charge will flow in the secondary
winding of the transformer and transfer energy from the primary circuit to the load. In
an ideal transformer, the induced voltage in the secondary winding (VS) is a fraction of
the primary voltage (VP) and is given by the ratio of the number of secondary turns to
the number of primary turns:
By appropriate selection of the numbers of turns, a transformer thus allows an
alternating voltage to be stepped up — by making NS more than NP — or stepped
down, by making it less. Transformers are some of the most efficient electrical
'machines', with some large units able to transfer 99.75% of their input power to their
output. Transformers come in a range of sizes from a thumbnail-sized coupling
transformer hidden inside a stage microphone to huge units weighing hundreds of tons
used to interconnect portions of national power grids.
APPLICATIONS:
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A major application of transformers is to increase voltage before transmitting electrical
energy over long distances through wires. Wires have resistance and so dissipate
electrical energy at a rate proportional to the square of the current through the wire. By
transforming electrical power to a high-voltage (and therefore low-current) form for
transmission and back again afterwards, transformers enable economic transmission of
power over long distances. Transformers are also used extensively in electronic
products to step down the supply voltage to a level suitable for the low voltage circuits
they contain. The transformer also electrically isolates the end user from contact with
the supply voltage.
Signal and audio transformers are used to couple stages of amplifiers and to match
devices such as microphones and recor d player cartridges to the input impedance of
amplifiers. Audio transformers allowed telephone circuits to carry on a two-way
conversation over a single pair of wires. Transformers are also used when it is necessary
to couple a differential-mode signal to a ground-referenced signal, and for isolation
between external cables and internal circuits.
CONNECTORS:
An electrical connector is a conductive device for joining electrical circuits together.
The connection may be temporary, as for portable equipment, or may require a tool for
assembly and removal, or may be a permanent electrical joint between two wires or
devices. Connectors may join two lengths of flexible wire or cable, or may connect a
wire or cable to an electrical terminal.
Properties of Electrical connector:
An ideal electrical connector would have a low contact resistance and high insulation
value. It would be resistant to vibration, water, oil, and pressure. It would be easily
mated/unmated, unambiguously preserve the orientation of connected circuits,
reliable, carry one or multiple circuits. Desirable properties for a connector also include
easy identification, compact snize, rugged construction, durability (capable of many
connect/disconnect cycles), rapid assembly, simple tooling, and low cost. No single
connector has all the ideal properties.
Power Connectors:
Domestic AC power plugs and sockets, NEMA connectors, Industrial and multiphase
power plugs and sockets for discussions of connectors used for electric power. Power
connectors must protect people from accidental contact with energized conductors.
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Power connectors often include a safety ground connection as well as the power
conductors. In larger sizes, these connectors must also safely contain any arc produced
when an energized circuit is disconnected or may require interlocking to prevent
opening a live circuit.
Fig.1.21: Power connectors
Above figure shows a common type of 115 VAC receptacle used to connect the power
cord to things such as personal computers and test equipment and a "Jones" or "Cinch-
Jones" connector. These have been around for decades, and are used in applications
such as supplying power to a DC motor.
Audio Connectors:
Fig. below shows what is commonly called an "RCA" plug and jack. They are two-
conductor connectors typically used with shielded cable. They are used in applications
such as connecting microphones and small speakers to audio amplifiers.
Fig. 1.22: Audio connectors
Modular telephone Connectors:
These are used with UTP (unshielded twisted pair) cables. Fig. shows an RJ11 connector
commonly used with 4-wire telephone cables. An RJ12 connector is the same size but
used with 6-wire cable. Fig. below shows an RJ45 connector used with 8-wire local area
network (LAN) cables.
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Fig.1.23: modular telephone connectors
BNC and UHF connectors
Fig. below shows a BNC cable commonly used with shielded cable, such as RG58,
carrying RF signals. Exactly what BNC stands for is unclear, but most people think the
B is for bayonet because of the way the connector locks on to the receptacle. BNC
connectors are common on electronics test equipment such as oscilloscopes.
Fig.1.24: BNC and UHF connectors
Fig. below, shows a UHF connector (UHF stands for Ultra High Frequency). Like the
BNC connector, it is used on coaxial cables carrying RF signals. It can be used on thicker
cable such as RG8. A UHF connector is threaded to screw onto the receptacle.
Fig. 1.25
D-Shell connectors:
Fig. 1.26 (A) Fig. 1.26 (B)
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Fig. (A) shows a DB9 connector. Fig. (B) shows a so-called Centronics connector
commonly used for the printer port of a PC.
Fig. 1.27: Edge Connectors:
Insulation Displacement Connectors (IDCs)
Fig.1.28: (A) (B) (C)
Fig. above shows the types of connectors used with ribbon cables. Fig. A is a "DIP"
connector, which can plug into a standard IC DIP socket. The connector of Fig. B mates
a "header", which has pins on 0.1" centers and is common on circuit boards. The
connector of Fig. C is a "shrouded" header.
Plug and Socket Connectors:
Fig.:1.29 A male plug made by Amphenol
Plug and socket connectors are usually made up of a male plug and a female socket,
although hermaphroditic connectors exist, such as the original IBM token ring LAN
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connector. Plugs generally have one or more pins or prongs that are inserted into
openings in the mating socket. The connection between the mating metal parts must be
sufficiently tight to make a good electrical connection and complete the circuit. When
working with multi-pin connectors, it is helpful to have a pin out diagram to identify
the wire or circuit node connected to each pin.
Fig.1.30: 8P8C connector crimped to cable
8P8C is short for "eight positions, eight conductors", and so an 8P8C modular connector
(plug or jack) is a modular connector with eight positions, all containing conductors.
D-subminiature connectors:
Fig.1.31: A male DE-9 plug.
The D-subminiature electrical connector is commonly used for the RS 232 serial port on
modems and IBM compatible computers. The D-subminiature connector is used in
many different applications, for computers, telecommunications, and test and
measurement instruments. A few examples are monitors (MGA, CGA, EGA), the
Commodore 64, MSX, Apple II, Amiga and Atari joysticks and mice, and game consoles
such as Atari, Sega and Amiga.
USB Connectors
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Fig. 1.32: A male USB series A plug
The Universal Serial Bus is a serial bus standard to interface devices, founded in 1996.
It is currently widely used among PCs, Apple Macintosh and many other devices. There
are several types of USB connectors, and some have been added as the specification has
progressed. The most commonly used is the (male) series "A" plug on peripherals, when
the cable is fixed to the peripheral. If there is no cable fixed to the peripheral, the
peripheral always needs to have a USB "B" socket. In this case a USB "A" plug to a USB
"B" plug cable would be needed. USB "A" sockets are always used on the host PC and
the USB "B" sockets on the peripherals. It is a 4-pin connector, surrounded by a shield.
There are several other connectors in use, the mini-A, mini- B and mini-AB plug and
socket (added in the On-The-Go Supplement to the USB 2.0 Specification).
SWITCHES:
In electronics, a switch is an electrical component which can break an electrical circuit,
interrupting the current or diverting it from one conductor to another. The most
familiar form of switch is a manually operated electromechanical device with one or
more sets of electrical contacts. Each set of contacts can be in one of two states: either
'closed' meaning the contacts are touching and electricity can flow between them, or
'open', meaning the contacts are separated and nonconducting.
Fig. 1.33: Three pushbutton switches. Major scale is inches
There are three important features to consider when selecting a switch:
• Contacts (e.g. single pole, double throw)
• Ratings (maximum voltage and current)
• Method of Operation (toggle, slide, key etc.)
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Switch Contacts
Several terms are used to describe switch contacts:
• Pole - number of switch contact sets.
• Throw - number of conducting positions, single or double.
• Way - number of conducting positions, three or more.
• Momentary - switch returns to its normal position when released.
• Open - off position, contacts not conducting.
• Closed - on position, contacts conducting, there may be several on positions.
For example: the simplest on-off switch has one set of contacts (single pole) and one
switching position which conducts (single throw). The switch mechanism has two
positions: open (off) and closed (on), but it is called 'single throw' because only one
position conducts.
Switch Contact Ratings
Switch contacts are rated with a maximum voltage and current, and there may be
different ratings for AC and DC. The AC values are higher because the current falls to
zero many times each second and an arc is less likely to form across the switch contacts.
For low voltage electronics projects the voltage rating will not matter, but you may need
to check the current rating. The maximum current is less for inductive loads (coils and
motors) because they cause more sparking at the contacts when switched off.
Standard Switches
Type of Switch Circuit Symbol Example
ON-OFF
Single Pole, Single Throw = SPST
A simple on-off switch. This type can be
used to switch the power supply to a
circuit. When used with mains
electricity this type of switch must be in
the live wire, but it is better to use a
DPST switch to isolate both
SPST toggle switch
(ON)-OFF
Push-to-make = SPST Momentary
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A push-to-make switch returns to its
normally open (off) position when you
release the button, this is shown by the
brackets around ON. This is the
standard doorbell switch.
Push-to-make switch
ON-(OFF)
Push-to-break = SPST Momentary
A push-to-break switch returns to its
normally closed (on) position when you
release the button.
Push-to-break switch
ON-ON
Single Pole, Double Throw = SPDT
This switch can be on in both positions,
switching on a separate device in each
case. It is often called a changeover
switch. For example, a SPDT switch can
be used to switch on a red lamp in one
position and a green lamp in the other
position.
ON-OFF-ON
SPDT Centre Off
A special version of the standard SPDT
switch. It has a third switching position
in the centre which is off. Momentary
(ON)-OFF-(ON) versions are also
available where the switch returns to
the central off position when released.
SPDT toggle switch
SPDT slide switch
(PCB mounting)
SPDT rocker switch
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Dual ON-OFF
Double Pole, Single Throw = DPST
A pair of on-off switches which operate
together (shown by the dotted line in
the circuit symbol).A DPST switch is
often used to switch mains electricity
because it can isolate both the live and
neutral connections.
DPST rocker switch
Dual ON-ON
Double Pole, Double Throw = DPDT
A pair of on-on switches which operate
together (shown by the dotted line in
the circuit symbol).
A DPDT switch can be wired up as a
reversing switch for a motor as shown
in the diagram.
ON-OFF-ON
DPDT Centre Off
It has a third switching position in the
centre which is off. This can be very
useful for motor control because you
have forward, off and reverse positions.
.
DPDT slide switch
Wiring for Reversing
Switch
SPECIAL SWITCHES
Type of Switch Example
Push-Push Switch (e.g. SPST = ON-OFF)
This looks like a momentary action push switch but it is a
standard on-off switch: push once to switch on, push
again to switch off. This is called a latching action.
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Micro switch (usually SPDT = ON-ON)
Micro switches are designed to switch fully open or closed
in response to small movements. They are available with
levers and rollers attached.
Key switch
A key operated switch. The example shown is SPST.
Tilt Switch (SPST)
Tilt switches contain a conductive liquid and when tilted
this bridges the contacts inside, closing the switch. They
can be used as a sensor to detect the position of an object.
Some tilt switches contain mercury which is poisonous.
Reed Switch (usually SPST)
The contacts of a reed switch are closed by bringing a
small magnet near the switch. They are used in security
circuits, for example to check that doors are closed.
Standard reed switches are SPST (simple on-off) but SPDT
(changeover) versions are also available.
DIP Switch (DIP = Dual In-line Parallel)
This is a set of miniature SPST on-off switches, the
example shown has 8 switches. The package is the same
size as a standard DIL (Dual In-Line) integrated circuit.
This type of switch is used to set up circuits, e.g. setting
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 25
the code of a remote control.
Multi-pole Switch
The picture shows a 6-pole double throw switch, also
known as a 6-pole changeover switch. It can be set to have
momentary or latching action. Latching action means it
behaves as a push-push switch, push once for the first
position, push again for the second position etc.
Multi-way Switch
Multi-way switches have 3 or more conducting positions.
They may have several poles (contact sets). A popular
type has a rotary action and it is available with a range of
contact arrangements from 1-pole 12-way to 4-pole 3 way.
The number of ways (switch positions) may be reduced by
adjusting a stop under the fixing nut. For example if you
need a 2-pole 5-way switch you can buy the 2-pole 6-way
version and adjust the stop.
Contrast this multi-way switch (many switch positions)
with the multi-pole switch (many contact sets) described
above.
Multi-way rotary switch
1-pole 4-way switch
symbol
CONCLUSION:
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 26
OBJECTIVE:
1. To study different controls of DMM and measurement of parameters like AC
and DC voltage, current
2. To study controls of CRO, Measurement of frequency, phase, AC & DC Voltages.
3. To study various controls of signal generator.
THEORY:
DMM: A multimeter or a multitester, also known as a volt/ohm meter or VOM, is an
electronic measuring instrument that combines several functions in one unit. A
standard multimeter may include features such as the ability to measure voltage,
current and resistance.
Fig. 2.1 : Front panel of DMM
ASSIGNMENT NO. 2
TITLE: STUDY OF DIFFERENT ELECTRONIC MEASURING
INSTRUMENTS
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 27
A multimeter can be a hand-held device useful for basic fault finding and field service
work or a bench instrument which can measure to a very high degree of accuracy. They
can be used to troubleshoot electrical problems in industrial and household devices
such as batteries, motor controls, appliances, power supplies, and wiring systems
PROCEDURE:
MEASUREMENT OF AC VOLTAGE, DC VOLTAGE & DC CURRENT:
1) Connect red test lead to “V”input terminal and black test lead to“COM” input
terminal.
2) Set Function/Range switch to desired voltage type (DC or AC) and range. If
magnitude of voltage is not known, set switch to the highest range and reduce until
a satisfactory reading is obtained.
3) Turn off power to the device or circuit being tested.
4) Connect test leads to the device or circuit being measured.
5) Turn on power to the device or circuit being measured. Voltage value will appear on
the digital display along with the voltage polarity.
6) Turn off power to the device or circuit being tested prior to disconnecting test leads.
Current Measurement:
1) Connect red test lead to the “mA” input terminal for current measurements up to
200 milliamperes. Connect black lead to the COM input terminal.
2) Set Function/Range switch to desired current type (DC or AC) and range. If
magnitude of current is not known, set switch to the highest range and reduce until
a satisfactory reading is obtained.
3) Turn off power to the device or circuit being tested.
4) Open the circuit in which current is to be measured. Now securely connect test leads
in series with the load in which current is to be measured.
5) Turn on power to the device or circuit being tested.
6) Read current value on digital display.
7) Turn off all power to the device or circuit being tested.
8) Disconnect test leads from circuit and reconnect circuit that was being tested.
9) For current measurement of 200mA or greater, connect the red test lead to “20 A”
input terminal & black test lest lead to the “COM” input terminal.
The central knob has lots of positions and you must choose which one is appropriate
for the measurement you want to make.If the meter is switched to 20 V DC,for
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 28
example,then 20 V is the maximum voltage which can be measured,this is
sometimes called 20 V fsd, fsd is full scale deflection.
1. Additionally, multimeter may also measure:
2. Capacitance in farads
3. Frequency in Hertz
4. Duty cycle as a percentage.
5. Temperature in degree Celsius or Farenheit.
6. Conductance in Siemens
7. Inductance in henry
8. Continuity that beeps when a circuit conducts.
9. Diodes and transistor testing
For safety reasons, you must NEVER connect a multimeter to the mains supply.
Observation Table:
1. Resistors (fixed value)
By using color code Using DMM
2. Variable resistors:
Theoretical value of Potentiometer-
Min value-
Max value-
3. Capacitor (Fixed value):
By using color code
And value on
capacitor
Using DMM
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
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4. AC voltage and current:
Reading on the
CRO Vpp
Vrms by
calculation
Using DMM
5. DC voltage and current:
Reading on DC power
supply
Using
DMM
DC current
theoretical
Measured Dc
current
6. Diode testing:
7. Transistor testing:
CATHODE RAY OSCILLOSCOPE (CRO):
The cathode-ray oscilloscope (CRO) is a common laboratory instrument that provides
accurate time and amplitude measurements of voltage signals over a wide range of
frequencies. Its reliability, stability, and ease of operation make it suitable as a general
purpose laboratory instrument. The heart of the CRO is a cathode-ray tube shown
schematically in Fig.. 1. The cathode ray is a beam of electrons which are emitted by the
heated cathode (negative electrode) and accelerated toward the fluorescent screen. The
assembly of the cathode, intensity grid, focus grid, and accelerating anode (positive
electrode) is called an electron gun. Its purpose is to generate the electron beam and
control its intensity and focus. Between the electron gun and the fluorescent screen are
two pair of metal plates - one oriented to provide horizontal deflection of the beam and
one pair oriented to give vertical deflection to the beam. These plates are thus referred to
as the horizontal and vertical deflection plates. The combination of these two deflections
allows the beam to reach any portion of the fluorescent screen. Wherever the electron
beam hits the screen, the phosphor is excited and light is emitted from that point. This
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 30
conversion of electron energy into light allows us to write with points or lines of light on
an otherwise darkened screen.
Fig. 2.2: Front panel of CRO
As you can see, the screen of this oscilloscope has 8 squares or divisions on the vertical
axis, and 10 squares on divisions on the horizontal axis. Usually, these squares are 1 cm
in each direction.
FRONT PANEL CONTROLS
1. POWER ‘On/Off’ : Rocker switch for supplying power to instrument.
2. X10 : Switch when pushed gives 10 times magnification of the
X signal.
3. FOCUS : Controls the sharpness of the trace.
4. XY : Switch when pressd cut off the time base & allows access to
the external horizontal signal to be fed through CH2(used
for X-Y display).
5. CH1/2, Trig ½ : Switch selects channel & trigger source(released CH1
& pressed CH2)
6. Ext : Switch when pressed allows external triggering signal to be
fed from the socket marked Trigger input (24).
7. Alt : Selects alternate trigger mode from CH1 & CH2.In this
mode both the signals are synchronized.
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8. Slope (+/-) : Switch selects the slope of triggering, whether positive
going or negative going.
9. Auto/level : Selects Auto/level position.Auto is used to get trace when
no signal is fed at the input. In Level position the trigger
level can be varied from the positive peak to negative peak
with level control.
10. Level : Controls the trigger level from peak to peak amplitude of
signal.
11. Component tester : Switch when pressed starts CT operation.
12. X shift : Controls horizontal position of the trace.
13. TB Var : Controls the time speed in between two steps of the
Time/Div switch. For calibration put this pot fully
anticlockwise at Cal position.
14. TR : Trace rotation controls the alignment of the trace with
graticule (screw driver adjustment).
15. Cal out : Socket provided for square wave output 200mV used for
probe compensation and checking vertical sensitivity,etc.
16. Volts/div. : Switch selects Volt/Div.step for CH1 & CH2
17. CH1(Y) & CH2(X) : BNC connectors serve as input connection for CH1 & CH2
input connector also serves as horizontal external input.
18. Time/Div. Switch selects Time/Div. steps
19. Component tester input: To test any componenet in the CT mode, put one test probe
in this socket and connect the other test prod in ground
socket.
20. Trigger Input : Socket provided to feed external trigger signal in External
Trigger mode.
21. Invert CH2 : Switch when pressed invert polarity of CH2.
22. Digital Readout : LCD window for displaying Digital Readout for Volt/Div.
& Time/Div. settings.
23. Y shift 1 & 2 : Controls provided for verticak deflection of trace for each
channel.
24. AC/ DC /GND : Input coupling switch for each channel. In AC the signal is
coupled through 0.1MFD capacitor.
25. Alt / Chop/Add : Switch Selects alternate or chopped in Dual mode.If Mono
is selected then this switch enables addition or subtraction of
channel i.e.CH1 ± CH2.
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 32
26. Intensity : Controls the brightness of the trace.
27. Mono/dual : Switch selects Mono or Dual trace operation.
Measurement of Different Parameters
1) Frequency Measurement:
1. Connect the signal from the signal generator to the Y-input/X-input.
2. Adjust the time base generator switch (time/div) to get a steady pattern of
the signal on the CRO screen.
3. Measure the time interval T for one cycle.
4. Determine the frequency F of the signal (F=l/T )
5. Repeat the same procedure for different frequencies.
2) DC voltage measurement:
1. Adjust the beam to certain reference level
2. Keep AC/DC selector switch on DC position.
3. Apply test voltage to CRO input.
4. Measure the shift of beam from reference level.
6. Calculate D.C. Voltage No. of divisions on y – axis x Volts/Div.
7. Note down the reading.
3) AC voltage measurement:
1. Keep AC/DC selector switch on AC position.
2. Apply AC voltage from signal generator to CRO input.
3. Measure no. of divisions on y – axis.
4. Calculate A.C. Voltage No. of divisions on y – axis x Volts/Div.
4) Phase measurement:
1. Phase difference α between two signals (same frequency) is obtained by feeding
the signals to two inputs X and Y of a dual trace CRO.
2. Set the CRO to XY mode. Keep Dual /Mono on Mono Position.
3. A Lissajous pattern is produced on the screen when two sine wave voltages are
applied simultaneously to both pairs of deflection plates of a CRO
4. The phase difference between two sinusoidal signals of same frequency can be
Calculated from the amplitudes Y1 and Y2 of the Lissajous pattern. Phase
difference is given by α = Sin-1 (Y1/Y2)
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 33
(a) (b)
Fig.2.3: a) Phase difference between two signals
b) Lissajous pattern
OBSERVATION TABLE:
PHASE MEASUREMENT
Function
Vertical
Division
(a)
Volt/div
(b)
Amplitude
(p-p)
V=a*b
Horizontal
Div (c)
Time/div
(d)
Time
T =c*d
Freq.
F=1/T
Sine
wave
Square
Wave
Sr. No Y1 = Y2 =
Phase Angle
α = Sin-1 (Y1/Y2)
(degree)
1
2
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 34
Draw observed waveforms:
Sine wave: (Amplitude: Frequency: )
Square wave: (Amplitude: Frequency: )
Questions:
1. What is the use of C.R.O.?
2. What is the highest frequency that can be measured by C.R.O. available in your
laboratory?
3. What is the highest voltage that can be measured by C.R.O. available in your
laboratory?
4. What you will do to measure voltage which is greater than voltage limit of the
C.R.O.?
5. Why AC/DC input coupling push-button switch is given?
6. What do you mean by dual channel C.R.O.?
7. How to test whether CRO probe is in working condition or not?
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 35
Component Tester
Oscilloscope comes with an additional facility, built-in Components tester. This allows
passive and active components like resistors, capacitors, inductors, transformer, silicon
or germanium diodes, Zener diodes, tunnel diodes, schottky diodes, transistors, JFETs,
MOSFETs, UJTs, SCRs, TRIACs, and even linear and digital ICs to be tested while still
in circuit.
Just push in the CT switch, plug in two test prods (supplied with instrument) one at the
Banana socket marked CT and the other at the ground socket. A horizontal line about 5
to 6 cms will be seen. On shorting the two tests prod tips a vertical line is seen. Connect
the component under test across the probs. Some typical test patterns are shown on the
following figure. Only remember to keep the scope in the "CH 1" operating mode and
Ground the input of CH 1.
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 36
SIGNAL GENERATOR:
Signal Generator provides various signals like sine wave, square wave for
different test circuits. Its frequency range varies from 1Hz to 1MHz with adjustable
amplitude, for sine wave 0 to 10V, for square wave 0 to 20V peak to peak. The output
impedance of generator is 600Ω at output level of 1V & below. The front panel of signal
generator is shown in Fig. 2.4
Fig.2.4: Front panel controls
FRONT PANEL CONTROLS:
1. Power ‘On/Off ‘ : At the rear side of the instrument, Power can be Switched
On or Off.
2. LCD Display : 16x2 Character bright back lit Liquid Crystal Display.
3. Frequency : Used for selection of frequency range in seven decade
Steps.
4. Function : Used for selection of Particular waveform.
5. Attenuation : Attenuation in two steps, ±20 dB and Variable attenuation
From 0 to 20dB Total of 60 dB.
6. FG/ FC : Used for selection of Function Generator or frequency
counter mode.
7. FM AMPL (adjusting knob) : Attenuation of input voltage for FM-input. This
Permits the user to change the sweep width.
8. Dc Offset (adjusting knob) : Adjustment of the positive or negative offset voltage.
This DC voltage can be superimposed on the output signal.
9. Trigger Variable : When trigger output is selected in CMOS output can be set
with Variable, to approximately 15 Vpp.
10. Frequency Variable(adjusting knob) : Continuous and linear frequency adjustment
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 37
From 0.1 Hz to 1 MHz in seven decade steps, selected with
frequency range.
11. Amplitude Variable : Continuous adjustment of the output amplitude from 22n
Vpp - 30 Vpp.
12. Output (BNC connector) : The output impedence is 50Ω/600 Ω switch selectable.
Maximum output amplitude is 30Vpp(open-circuit) or 15
Vpp when terminated with 50 Ω.
13. 50 Ω / 600 Ω : Push button when pressed, selects 600 Ω else 50 Ω.
14. Trigger Output (BNC connector) : This output supplies a square wave signal in
Synchronous with the output signal. It is switch selectable
TTL/CMOS and has a duty –factor of approximately 50%.
15. TTL/CMOS : Push button when pressed, selects CMOS else TTL.
16. FM Input (BNC Connector) : Applying a DC voltage to this input will vary the
oscillator frequency linearly to maximum 1:100. The
maximum allowable input voltage is +30 Vpp.
17. External counter(BNC Connector) : Input BNC connector for measuring the
frequency of external signal when external counter mode is
selected by Individual key(6) on LCD Screen.
CONCLUSION:
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 38
OBJECTIVE: For a given Regulated power supply circuit with bridge rectifier,
capacitor filter and three terminal regulator:
1. Identify pins of rectifier Diode (such as 1N4001) and study of its data sheet
specifications.
2. Identify pins of three pin regulator (such as LM 78XX or 79XX) and study of its
data sheet specifications.
3. To measure voltage and observe waveform at transformer secondary, output of
Bridge rectifier, output of regulator.
THEORY:
The p-n junction forms a popular device called p-n junction semiconductor diode. The
p-n junction has two terminals called electrodes, one each from p-region and n-region.
A rectifier is a device which converts A.C. voltage to pulsating D.C. voltage using one
or more diodes. The p-n junction diode conducts only in one direction i.e. when
forward biased and does not conduct when reverse biased. The rectifiers are broadly
classified ad half wave rectifier and full wave rectifier. The bridge rectifier is essentially
a full wave rectifier using 4 diodes forming the four arms of an electric bridge. To one
diagonal of the bridge the a.c. voltage is applied through a transformer and the rectified
voltage is taken from the other diagonal of the bridge.
It has been seen that the output of a rectifier is not a pure d.c, but it contains
fluctuations or ripple, which are undesired. To minimize the ripple content in the
output, filters are used. The filter is connected between the rectifier and the load. Ideally
the output of the filter should be pure d.c., but practically the filter circuits will try to
minimize the ripple at the output as far as possible. Two components can be used as
filters: inductors and capacitors because these components have different impedences
for a.c and d.c.. After the filters a regulator circuit is used which not only makes the d.c.
voltage smooth and almost ripple free but it also keeps the d.c output voltage constant
though input voltage varies under certain conditions.
1N4007: A diode is also called as a rectifier as it converts an alternating voltage into a
pulsating d.c. voltage. The 1N4007 is a semiconductor diode as shown with two
terminals called as anode and cathode. The terminal with a silver ring is the cathode
whereas the other terminal is the anode.
ASSIGNMENT NO. 3
TITLE: STUDY OF REGULATED POWER SUPPLY
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 39
Fig. 3.1: 1N4001 diode
Three Pin regulator ICs:
IC 78XX Series provides a fixed positive output voltage. The last two digits in the part
number indicates the D.C. output voltage. This Series provides fixed regulated voltages
from +5V to +24 V.
IC 79XX Series provides a fixed negative output voltage. This series provides fixed
regulated voltages from -5V to -24 V.
Fig.3.2
IC 7805: The 7805 regulator IC is as shown in the following Fig.. It is a three pin IC with
pin no 1 as input, 2 as ground and 3 as the regulated output.
IC 7905: The 7905 regulator IC is as shown in the following Fig.. It is a three pin IC with
pin no. 1 as Ground,2 as Input and 3 as the regulated output.
Fig. 3.3
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 40
CIRCUIT DIAGRAM:
Fig. 3.4: Circuit diagram of a power supply
PROCEDURE:
1. Trace the board as per the circuit diagram.
2. Note down the component values and device no.
3. Make the connection as per the circuit diagram.
4. Study the specifications of the diode 1N4001 from the given datasheet.
5. Study the specifications of the three pin regulator IC 7805 from the given
datasheet.
6. Measure voltage and observe the waveforms at:
i) Transformer secondary ii) output of bridge rectifier iii) output of regulator
OBSERVATIONS:
WAVEFORMS:
Note: Students are requested to draw the waveforms on the graph paper.
QUESTIONS:
1. What do you understand by regulated power supply? Draw the block diagram
of such a supply.
2. Write a short note on the need for regulated power supply.
3. What are the limitations of unregulated power supply?
4. How can you improve the regulation of an ordinary power supply?
5. Define Ripple factor?
6. What causes the ripple voltage on the output of a capacitor –input filter?
7. What is the difference between Line regulation and load regulation?
8. Draw the output waveforms at each stage in power supply design.
CONCLUSION:
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 41
OBJECTIVE: For a given BJT CE Amplifier circuit
1) Identify pins of a BJT (such as BC 547) and study of its data sheet specifications.
2) To measure voltages and observe waveforms at input and output terminals of
single stage BJT Common Emitter amplifier circuit.
3) Calculate voltage gain of the amplifier.
THEORY:
A transistor is a semiconductor device that can amplify electronic signals. It is a three
terminal device: emitter, base and collector and can be operated in one of the three
configurations namely common base, common collector and common emitter.
According to the configuration it can be used for voltage as well as current
amplification. The input signal of small amplitude is applied at the base to get the
magnified output signal at the collector. The amplification in the transistor is achieved
by passing input current signal from a low resistance to a region of high resistance. This
concept of transfer of resistance has given the name TRANSfer-resiISTOR
(TRANSISTOR). There are two types of transistors: Unipolar Junction transistors and
Bipolar Junction Transistor. In bipolar transistor, the current conduction is only due to
one type of carriers-majority carriers whereas in a bipolar junction transistor the
conduction is because of both types of carriers-electron and holes. The common emitter
configuration is widely used in amplifier circuits. This is because the CE configuration
is the only configuration which provides both voltage as well as current gain greater
than unity.
ASSIGNMENT NO. 4
TITLE: STUDY OF SINGLE STAGE BJT COMMON EMITTER
AMPLIFIER CIRCUIT
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 42
The BC 547 is a general purpose NPN transistor with its terminal as shown which can
be used for applications such as amplifiers and switch.
Fig. 4.1: Transistor BC 547
CIRCUIT DIAGRAM:
Fig. 4.2: Circuit diagram of CE amplifier
APPARATUS: Circuit board, Signal generator, CRO, CRO probes, connecting wires,
connecting wires, Dual DC power supply etc.
PROCEDURE:
1. Trace the board as per the circuit diagram.
2. Note down the component values and device no.
3. Make the connection as per the circuit diagram for CE configuration.
4. Apply sinusoidal input signal of 1 kHz frequency and 10 mVp-p amplitude.
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 43
5. Measure the output voltage (Vo) on CRO. Draw input output waveforms on
graph paper.
6. Now vary the input signal amplitude to 20mV, 30mV and 40mV and measure
the respective output voltages.
7. Calculate the voltage gain by using the formula A=Vo/Vin.
OBSERVATION TABLE:
Frequency=1 KHz constant (sine wave)
Vin(pp) Vo Gain=Vo/Vin
30 mV
50 mV
100 mV
2000 mV
WAVEFORMS:
QUESTIONS:
1. What do you understand by Single stage transistor amplifier?
2. Show the various currents and voltages in a single stage transistor amplifier?
3. What do you mean by frequency response of an amplifier?
4. Why there is phase reversal in single stage CE amplifier?
5. Does phase reversal affect amplification?
6. What is the significance of operating point?
7. Why have transistors inherent variations of parameters?
8. How transistors amplify?
CONCLUSION:
Basic Electronics laboratory manual
International Institute of Information Technology, Hinjawadi, Pune.
OBJECTIVE:
1) Identify pins of an op-amp (such as LM741)
2) Implement given voltage equation for 2 inputs with Op
and Difference amplifier(Vo=2 V
THEORY:
The operational amplifier most commonly known as an op
a variety of mathematical operations such as addition, subtraction, multiplication
etc.Op-amp is direct coupled high gain amplifier, usually consisting of one or more
differential amplifiers. An op
package.
The operational amplifier is a versatile device that can be used to amplify DC as well as
AC input signals and was originally designed for computing such mathematical
functions as addition, substation, multiplication, integration. Thus the name op
amplifier stems from its original use for these mathematical operations and is
abbreviated to op-amp with the addition of suitable external feedback components, the
modern day op-amp can be used for a variety of applications such as AC & DC signal
amplification, active filters, oscillators, comparator, regulators, and others.
BLOCK DIAGRAM REPRES
AMPLIFIER:
Since an op-amp is multistage amplifier, it can be represen
Fig.1.
ASSIGNMENT NO. 5
TITLE: STUDY OF OP
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune.
amp (such as LM741)
Implement given voltage equation for 2 inputs with Op-amp based summing
and Difference amplifier(Vo=2 V1+3V2 and Vo=4V1-V2)
The operational amplifier most commonly known as an op-amp can be used to perform
atical operations such as addition, subtraction, multiplication
amp is direct coupled high gain amplifier, usually consisting of one or more
differential amplifiers. An op-amp is available as a single integrated circuit (IC)
amplifier is a versatile device that can be used to amplify DC as well as
AC input signals and was originally designed for computing such mathematical
functions as addition, substation, multiplication, integration. Thus the name op
original use for these mathematical operations and is
amp with the addition of suitable external feedback components, the
amp can be used for a variety of applications such as AC & DC signal
filters, oscillators, comparator, regulators, and others.
BLOCK DIAGRAM REPRESENTATION OF A TYPICAL OPERATIONAL
amp is multistage amplifier, it can be represented as block diagram as show
ASSIGNMENT NO. 5
STUDY OF OP-AMP BASED AMPLIFIER CIRCUITS
Dept of Applied sciences and Engineering
Page 44
amp based summing
amp can be used to perform
atical operations such as addition, subtraction, multiplication
amp is direct coupled high gain amplifier, usually consisting of one or more
amp is available as a single integrated circuit (IC)
amplifier is a versatile device that can be used to amplify DC as well as
AC input signals and was originally designed for computing such mathematical
functions as addition, substation, multiplication, integration. Thus the name operational
original use for these mathematical operations and is
amp with the addition of suitable external feedback components, the
amp can be used for a variety of applications such as AC & DC signal
filters, oscillators, comparator, regulators, and others.
L OPERATIONAL
ted as block diagram as show
R CIRCUITS
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 45
Fig.5.1: Block diagram of a typical op-amp
The input stage is dual input balanced output differential amplifier. This stage generally
provides most of the voltage gain of the amplifier and also establishes the input
resistance of op-amp. The intermediate stage is usually another differential amplifier,
which is driven by the output of first stage. In most amplifiers the intermediate stage is
dual input unbalanced output. Because the direct coupling is used, the dc voltage at the
output of intermediate stage is well above ground potential. Therefore, generally the
level translator (shifting) circuit is used after the intermediate stage to shift the dc level
at the output of intermediate stage downward to zero volts with respect to ground. The
final is usually a push-pull complementary amplifier output stage. The output stage
increases the output voltage swing and raises the current supplying capability of the
op-amp. A well-designed output stage also provides low output resistance.The op-amp
is available in an IC as shown. It is an 8 pin IC with the following terminals.
Fig. 5.2: IC 741 op-amp
V- (pin 2) and V+ (pin 3) are the inverting and non-inverting inputs, respectively. Vout
(pin 6) is the output. +Vcc (pin 7) and –Vcc (pin 4) are the two power supply voltages
needed to power the op-amp. For the 741, +Vcc is +15 V and –Vcc is -15 V. The two
supply voltages limit the output voltage range (from +Vcc to –Vcc). If the gain would
yield an output voltage above +Vcc or below -Vcc, then the output “saturates” at +Vcc
or -Vcc, respectively.
The opamp can be used as an adder or a summing amplifier and a subtractor or a
difference amplifier as shown below.
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 46
Fig.5.3: summing amplifier Fig.5.4: difference amplifier
As the input impedence of an op-amp is extremely large, more than one input signal
can be applied to the inverting amplifier. Such circuit gives the addition of the applied
signals at the output. Hence it is called as a summing amplifier or an adder circuit.
Depending upon the sign of the output, the adders are classified as inverting or non-
inverting summing amplifier. Fig. 3 shows an inverting summing amplifier where all
the signals to be added are applied to the inverting input terminal of the opamp. The
circuit shows an adder with two inputs and a negative feedback is used. The output of
the circuit is:
If the resistances are equal i.e. R1=R2= then
Vo = -(V1+V2)
Thus the magnitude of the output voltage is the sum of the input voltages and hence the
circuit is called as an adder. We have to design an adder for the equation:
Vo=2V1+3V2.
Referring above equation , we can say that:
2 and
3
Therefore if RF=10KΩ then R1=5KΩ and R2=3.3KΩ
Fig. 4 shows a difference amplifier which performs subtraction of the two input
voltages. The output voltage is given by:
( )
If Rf = R1 then
Vo=V2-V1
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 47
By selecting proper values of R1, R2 and Rf we can have the subtraction of two inputs
with appropriate strengths like: Vo=aV2-bV1.
APPARATUS: Circuit board, Signal generator, CRO, CRO probes, connecting wires,
connecting wires, Dual DC power supply etc
PROCEDURE:
1. Trace the board as per the circuit diagram.
2. Note down the component values and device no.
3. Make the connection as per the circuit diagram for summing amplifier.
4. Apply the inputs and measure the output voltage.
5. Make the connection as per the circuit diagram for difference amplifier.
6. Apply the inputs and measure the output voltage.
OBSERVATION TABLES:
1. Adder: 2. Subtractor:
QUESTIONS:
1. What is an Operational Amplifier?
2. What is a Differential Amplifier?
3. What do you mean by inverting and non-inverting input of a differential
Amplifier?
4. What do you mean by slew rate of an OPamp?
5. Discuss two applications of Summing amplifier?
6. What is the need of negative feedback in an OPamp?
7. What is a voltage follower?
8. What do you mean by Open loop voltage gain and closed loop voltage gain of an
OPamp?
CONCLUSION:
Sr. No
Input voltage Output
voltage
V1 V2
1
2
3
Sr. No Input voltage
Output
voltage
V1 V2
1
2
3
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 48
OBJECTIVE:
1. Identify pins of IC 555 Timer
2. Observe output Observe output waveform and measure frequency of output
wave for IC 555 timer used in Astable mode
THEORY: The 555 timer is an extremely versatile integrated circuit which can be used
to build lots of different circuits. This IC is a monolithic timing circuit that can produce
accurate and highly stable time delays or oscillation. Like other commonly used op-
amps, this IC is also very much reliable, easy to use and cheaper in cost. It has a variety
of applications including monostable and astable multivibrators, digital logic probes,
waveform generators, analog frequency meters and tachometers, and control devices,
voltage regulators etc. The timer basically operates in one of the two modes either as a
monostable (one-shot) multivibrator or as an astable (free-running) multivibrator. The
pin diagram of IC 555 is as follows:
Fig. 6.1: IC 555 pin diagram
Pin 1: Grounded Terminal: All the voltages are measured with respect to this terminal.
Pin 2: Trigger Terminal: This pin is an inverting input to a comparator that is
responsible for transition of flip-flop from set to reset. The output of the timer depends
on the amplitude of the external trigger pulse applied to this pin.
Pin 3: Output Terminal: Output of the timer is available at this pin. There are two ways
in which a load can be connected to the output terminal either between pin 3 and
ASSIGNMENT NO. 6
TITLE: STUDY OF IC 555 TIMER CIRCUIT
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 49
ground pin (pin 1) or between pin 3 and supply pin (pin 8). The load connected
between pin 3 and ground supply pin is called the normally on load and that connected
between pin 3 and ground pin is called the normally off load.
Pin 4: Reset Terminal: To disable or reset the timer a negative pulse is applied to this
pin due to which it is referred to as reset terminal. When this pin is not to be used for
reset purpose, it should be connected to + VCC to avoid any possibility of false
triggering.
Pin 5: Control Voltage Terminal: The function of this terminal is to control the
threshold and trigger levels. Thus either the external voltage or a pot connected to this
pin determines the pulse width of the output waveform. The external voltage applied to
this pin can also be used to modulate the output waveform. When this pin is not used, it
should be connected to ground through a 0.01 micro Farad to avoid any noise problem.
Pin 6: Threshold Terminal: This is the non-inverting input terminal of comparator 1,
which compares the voltage applied to the terminal with a reference voltage of 2/3 VCC.
The amplitude of voltage applied to this terminal is responsible for the set state of flip-
flop.
Pin 7: Discharge Terminal: This pin is connected internally to the collector of transistor
and mostly a capacitor is connected between this terminal and ground. It is called
discharge terminal because when transistor saturates, capacitor discharges through the
transistor. When the transistor is cut-off, the capacitor charges at a rate determined by
the external resistor and capacitor.
Pin 8: Supply Terminal: A supply voltage of + 5 V to + 18 V is applied to this terminal
with respect to ground (pin 1).
ASTABLE MULTIVIBRATOR:
Astable multivibrator has one stable state and one quasi stable state. The circuit is
useful for generating single output pulse of time duration in response to a triggering
signal.The width of output pulse depends on external components connected to the op-
amp.
DESIGN EQUATIONS:
Charging time (output high): 0.693*(R1+R2)*C
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 50
Discharging time (output low): 0.693*R2*C
Total time period: 0.693*(R1+2*R2)
CIRCUIT DIAGRAM:
Fig. 6.2: Circuit diagram of Astable Multivibrator
APPARATUS: Bread board, CRO, CRO probes, connecting wires, power supply
PROCEDURE:
1. Trace the board as per the circuit diagram.
2. Note down the component values and device no.
3. Make the connection as per the circuit diagram for astable multivibrator.
4. Apply +5V supply and observe the output signal.
5. Measure TON and TOFF of the output waveform and theoretical values are verified
with practical values.
6. Calculate duty cycle and frequency.
OBSERVATION TABLE:
TON =
0.69(R1+R2)C
TOFF =
(0.069R2C)
T =
(TON+TOFF)
Frequency % Duty cycle
Calculated Observed
(1/T) Calculated
Observed
(TON/(TON+TOFF))
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 51
CALCULATIONS:
For the given circuit:
R1 = ------, R2 = -------, C = ---------;
F = .
-------------------------------theoretical frequency
% Duty cycle =
OUTPUT WAVEFORMS:
QUESTIONS:
1. What is a Multivibrator?
2. What are the different types of multivibrator?
3. What are the basic components of an oscillator circuit?
4. Name the five basic elements in a 555 timer IC.
5. When the 555 timer is configured as an astable multivibrator, hoe is the duty
cycle determined?
6. What are the two comparator reference voltages In a 555 timer when Vcc=10V.
7. How to set duty cycle more than 50% and less than 50%.
8. To what value must c can be changed in ckt given to acheve a frequency of
25kHz?
CONCLUSION:
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 52
OBJECTIVE: Study of digital circuits
1. Identify pins of Digital logic gate ICs such as AND, OR, NOT, EX-OR, NAND
2. Implement Half Adder and full Adder circuit with basic logic gate ICs
THEORY:
The electronics system or circuit in which the voltage levels assume a finite number of
discrete values is called as a digital system. The digital circuits are called logic circuits
as they process and represent logic voltage levels. The digital circuit uses binary logic
which consists of only two levels: high level and low level (logic 1 and logic 0). Logic
gate is a logic circuit which obeys a certain set of logic functions. The name logic gate is
derived from the ability of such a device to make decisions in response to different
combinations of the inputs. Various logic gates that are in use are NOT, AND, OR, Ex-
OR, NAND etc. All these logic gates are available in an IC form as shown below:
ASSIGNMENT NO. 7
TITLE: STUDY OF DIGITAL CIRCUITS
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 53
Fig. 7.1: Internal pin configuration of a NOT gate, AND gate, OR gate, NAND
gate and EX-OR gate
Truth Table of Basic logic gates is as shown below:
Logic circuit that performs binary addition is called electronic adder or adder. It
consists of properly added logic gates.
There are two types of adders
1. Half Adder 2.Full Adder
Basic Electronics laboratory manual
International Institute of Information Technology, Hinjawadi, Pune.
1. Half Adder:
The logic circuit that can add two binary bits (0 or 1) is called half adder.
block symbol of the half adder. The adder circuit would need two inputs and two
outputs. The two inputs are for two digits to be added either 0 or 1. One output
terminal is for the sum of the two inputs and other output is for the carry.
the addition table of the adder and called truth table.
The half adder would behave according to truth table
Fig. 7.2: Half Adder
Observing the truth table we can see that the output column (sum and carry) can be
produced by using two gates.
I) Sum column is the output of XOR gate
II) Carry column is output of AND gate.
Thus we can produce half adder us
shown in Fig. below.
Logic diagram:
Fig.7.
2. Full Adder:
A full adder adds two binary bits plus carry input (Cin) to produce th
(Co) outputs. Fig. 3 shows block diagram of full adder.
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune.
The logic circuit that can add two binary bits (0 or 1) is called half adder.
block symbol of the half adder. The adder circuit would need two inputs and two
outputs. The two inputs are for two digits to be added either 0 or 1. One output
inal is for the sum of the two inputs and other output is for the carry.
the addition table of the adder and called truth table.
The half adder would behave according to truth table.
Observing the truth table we can see that the output column (sum and carry) can be
produced by using two gates.
Sum column is the output of XOR gate
Carry column is output of AND gate.
Thus we can produce half adder using two input AND gate and two input XOR gate as
7.3: Logic Diagram of Half Adder
A full adder adds two binary bits plus carry input (Cin) to produce the Sum and Carry
3 shows block diagram of full adder.
Inputs Outputs
A B Sum Carry
0 0 0 0
0 1 1 0
1 0 1 0
1 1 0 1
Dept of Applied sciences and Engineering
Page 54
The logic circuit that can add two binary bits (0 or 1) is called half adder. Fig. 1 shows
block symbol of the half adder. The adder circuit would need two inputs and two
outputs. The two inputs are for two digits to be added either 0 or 1. One output
inal is for the sum of the two inputs and other output is for the carry. Fig. 7.2 shows
Observing the truth table we can see that the output column (sum and carry) can be
ing two input AND gate and two input XOR gate as
e Sum and Carry
Outputs
Carry
0
0
0
1
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 55
Fig. 7.4: Full Adder
It is formed by using two half adder circuit and an OR gate as shown in Fig. below.
Logic diagram:
Fig. 7.5: Logic Diagram of Full Adder
APPARATUS: Digital Trainer kit, connecting wires, basic gate ICs.
PROCEDURE:
1. Build the circuit as above on bread board.
2. Make the connections and apply the supply voltage.
3. See the result as per truth table
Inputs Outputs A B Cin Sum Carry 0 0 0 0 0 0 1 0 1 0 1 0 0 1 0 1 1 0 0 1 0 0 1 1 0 0 1 1 0 1 1 0 1 0 1 1 1 1 1 1
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 56
OBSERVATION TABLE:
Half Adder: Full Adder:
Inputs Outputs
A B Sum Carry
0 0
0 1
1 0
1 1
QUESTIONS:
1. What are the logic Gates?
2. What are the logic circuits, Logic function and logical variables?
3. Design a full adder using half adder.
4. Implement half adder and full adder using NAND gates only.
5. What are the universal gates? Why these are called so?
6. What is the drawback of half adder?
7. Design EX-OR gate using NAND gates only.
8. How to use Ex-OR Gate and EX-NOR gate as Inverter?
CONCLUSION:
Inputs Outputs
A B Cin Sum Carry
0 0 0
0 1 0
1 0 0
1 1 0
0 0 1
0 1 1
1 0 1
1 1 1
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 57
OBJECTIVE: Build and test any circuit using IC such as Op-amp LM 741, IC 555 timer,
LM 78XX, LM 79XX or any digital logic gate IC.
APPARATUS: Digital trainer kit, connecting wires, bread board, respective IC’s.
THEORY:
OBSERVATION TABLE:
ASSIGNMENT NO. 8
TITLE: BUILD AND TEST SIMPLE APPLICATION CIRCUIT
Basic Electronics laboratory manual Dept of Applied sciences and Engineering
International Institute of Information Technology, Hinjawadi, Pune. Page 58
CONCLUSION: