Date post: | 05-Apr-2018 |
Category: |
Documents |
Upload: | scribdashokram |
View: | 230 times |
Download: | 2 times |
of 18
7/31/2019 0.Basic Engineering Practice Electrical and Electronics Lab
1/18
BASIC ENGINEERING PRACTICE ELECTRICAL AND ELECTRONICS
LAB
LIST OF EXPERIMENTS
1. Study of Electrical and Electronic Components
I .a) Solid Conductor
b) Strandard Conductor
II. Fuses: Types of Fuses and Ratings
III. How to use a tester
IV. Single Phase Supply & Three Phase Supply
V. How to find the neutral link Cut
VI. Coding of Resistor (Each Student Should Be Given a Resistor)
VII. Identify a Capacitor (Condenser)
VIII. Identify an Inductor (Choke)
IX. Starter
X. Double Pole Single Throw Switch (DPST)
XI. Double Pole Double Throw Switch (DPDT)
XII. Insulator
XIII. Diode & Zener Diode
XIV.PN Junction Diode
2. Fluorescent Lamp Wiring
3. Staircase Wiring
4. Measurement of Electrical QuantitiesVoltage, Current, Power & Power Factor in RLC
Circuit.
5. Measurement of Energy Using Single Phase Energy Meter.
7/31/2019 0.Basic Engineering Practice Electrical and Electronics Lab
2/18
6. Residential House Wiring Using Switches Fuse, Indicator, Lamp and Energy Meter.
7. Measurement of Earth Resistance.
ELECTRONIC ENGINEERING PRACTICE
1. Characteristics of PN Junction Diode.
2. Characteristics of Zener Diode
3. Characteristics of BJT (any one)
4. Characteristics of JFET
5. Characteristics of Photo Diode
6. Verification of Logic Gates
7. Design and Implementation of Adders
7/31/2019 0.Basic Engineering Practice Electrical and Electronics Lab
3/18
ENGINEERING PRACTICES LABOURATORY
STUDY OF BASIC ELECTRICAL AND ELECTRONIC COMPONENTS
SOLID CONDUCTORS
It is made up of a single, solid conducting wire surrounded by an insulator.
STRANDED CONDUCTORS:
It is made up of a bundle of smaller wire strands. These are arranged so that several wires
(commonly 6 or 18) surround a single wire at the bundles center.
Fuse:
It is a type of sacrificial overcurrent protection device. Its essential component is a metal wire orstrip that melts when too much current flows, which interrupts the circuit in which it is
connected. A fuse interrupts excessive current (blows) so that further damage by overheating or
fire is prevented.Cartridge Fuses where the fuse element or the fuselink is located in a cartridge
and Wirable Fuses where the fuselink is a wire that is wired over a ceramic fuse carriers
Fuse rating:
the two basic ratings for fuses are the current rating, the current which, when exceeded, willcause the fuse will fail, and the voltage rating, the maximum voltage in the circuit in which the
fuse is to be safely used.
Tester
7/31/2019 0.Basic Engineering Practice Electrical and Electronics Lab
4/18
A low-cost type of test lamp only contacts one side of the circuit under test, and relies on
stray capacitance and current passing through the user's body to complete the circuit. The devicemay have the form of a screwdriver. The tip of the tester is touched to the conductor being tested
(for instance, it can be used on a wire in a switch, or inserted into a hole of an electric socket). A
neon lamp takes very little current to light, and thus can use the user's body capacitance to earth
ground to complete the circuit.
Neon-lamp type tester, which has no amplifier; this type requires a direct metallic contact to the
circuit to be tested.
Screwdriver-type test lamps are very inexpensive, but cannot meet the construction requirementsof UK GS 38. The long exposed shaft provides a shock hazard to the user, and the internal
construction of the tester provides no protection against short-circuit faults. Failure of the resistor
and lamp series network can put the user in direct metallic contact with the circuit under test.Even if an internal short circuit does not electrocute the user, the resulting electric shock may
result in a fall or other injury. The lamp provides no indication below the strike voltage of the
neon lamp, and so cannot detect certain hazardous leakage conditions.
Single phase supply
In electrical engineering, single-phase electric power refers to the distribution of alternating
current electric power using a system in which all the voltages of the supply vary in unison.Single-phase distribution is used when loads are mostly lighting and heating, with few largeelectric motors. A single-phase supply connected to an alternating current electric motor does not
produce a revolving magnetic field; single-phase motors need additional circuits for starting, and
such motors are uncommon above 10 or 20 kW in rating. Most household loads are single-phase
Standard frequencies of single-phase power systems are either 50 or 60 Hz.
Three phase supply
Three-phase electric power is a common method of alternating-current electric power
generation, transmission, and distribution. In a three-phase system, three circuit conductors carrythree alternating currents (of the same frequency) which reach their instantaneous peak values at
different times. Taking one conductor as the reference, the other two currents are delayed in timeby one-third and two-thirds of one cycle of the electric current. Three-phase systems may have a
neutral wire. A neutral wire allows the three-phase system to use a higher voltage while still
supporting lower-voltage single-phase appliances. In high-voltage distribution situations, it iscommon not to have a neutral wire as the loads can simply be connected between phases (phase-
phase connection).
http://en.wikipedia.org/wiki/File:Phasenpruefer_01-l_KMJ.jpghttp://en.wikipedia.org/wiki/File:Phasenpruefer_01-l_KMJ.jpghttp://en.wikipedia.org/wiki/File:Phasenpruefer_01-l_KMJ.jpghttp://en.wikipedia.org/wiki/File:Phasenpruefer_01-l_KMJ.jpg7/31/2019 0.Basic Engineering Practice Electrical and Electronics Lab
5/18
Generation and distribution
At the power station, an electrical generator converts mechanical power into a set of three AC
electric currents, one from each coil (or, winding) of the generator. The windings are arranged
such that the currents vary sinusoidally at the same frequency but with the peaks and troughs of
their wave forms offset to provide three complementary currents with a phase separation of one-third cycle (120 or
23 radians). The generator frequency is typically 50 or 60 Hz, varying by
country.
Large power generators provide an electric current at a potential which can be a few hundred
volts or up to about 30 kV. At the power station, transformers step this voltage up to one suitablefor transmission.
After numerous further conversions in the transmission and distribution network, the power is
finally transformed to the standard utilization voltage for lighting and equipment. Single-phase
loads are connected from one phase to neutral or between two phases. Three-phase loads such as
larger motors must be connected to all three phases of the supply.
Switch:
a switch has two conductive pieces, oftenmetal, called contacts, connected to an externalcircuit,
that touch to complete (make) the circuit, and separate to open (break) the circuit
http://en.wikipedia.org/wiki/Electrical_generatorhttp://en.wikipedia.org/wiki/Alternating_currenthttp://en.wikipedia.org/wiki/Electric_currenthttp://en.wikipedia.org/wiki/Sine_wavehttp://en.wikipedia.org/wiki/Wavehttp://en.wikipedia.org/wiki/Sine_wavehttp://en.wikipedia.org/wiki/Sine_wavehttp://en.wikipedia.org/wiki/Sine_wavehttp://en.wikipedia.org/wiki/Sine_wavehttp://en.wikipedia.org/wiki/Sine_wavehttp://en.wikipedia.org/wiki/Utility_frequencyhttp://en.wikipedia.org/wiki/Hertzhttp://en.wikipedia.org/wiki/Electrical_potentialhttp://en.wikipedia.org/wiki/Transformerhttp://en.wikipedia.org/wiki/Electric_power_transmissionhttp://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/Electric_circuithttp://en.wikipedia.org/wiki/Electric_circuithttp://en.wikipedia.org/wiki/Electric_circuithttp://en.wikipedia.org/wiki/File:3-phase_flow.gifhttp://en.wikipedia.org/wiki/File:3-phase_flow.gifhttp://en.wikipedia.org/wiki/File:3-phase_flow.gifhttp://en.wikipedia.org/wiki/File:3-phase_flow.gifhttp://en.wikipedia.org/wiki/Electric_circuithttp://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/Electric_power_transmissionhttp://en.wikipedia.org/wiki/Transformerhttp://en.wikipedia.org/wiki/Electrical_potentialhttp://en.wikipedia.org/wiki/Hertzhttp://en.wikipedia.org/wiki/Utility_frequencyhttp://en.wikipedia.org/wiki/Sine_wavehttp://en.wikipedia.org/wiki/Wavehttp://en.wikipedia.org/wiki/Sine_wavehttp://en.wikipedia.org/wiki/Electric_currenthttp://en.wikipedia.org/wiki/Alternating_currenthttp://en.wikipedia.org/wiki/Electrical_generator7/31/2019 0.Basic Engineering Practice Electrical and Electronics Lab
6/18
Inelectronics, a switch is anelectrical componentthat can break anelectrical circuit, interrupting
thecurrentor diverting it from one conductor to another.Switches are classified according to thearrangement of their contacts in electronics. A pair of contacts is said to be "closed" when
current can flow from one to the other. When the contacts are separated by aninsulating air gap,
they are said to be "open", and no current can flow between them at normal voltages. The terms
"make" for closure of contacts and "break" for opening of contacts are also widely used.
a "2-pole" switch has two separate identical sets of contacts controlled by the same knob. Thenumber of "throws" is the number of separate positions that the switch can adopt. A single-throw
switch has one pair of contacts that can either be closed or open. A double-throw switch has a
contact that can be connected to either of two other contacts,
SPST :
Single pole, single throw (One-way) .A simple on-off switch: The two terminals are eitherconnected together or disconnected from each other. An example is. a light switch
SPDT Single pole, double throw (Two-way). A simple changeover switch: C (COM, Common)
is connected to L1 or to L2
.
DPST
Double pole, single throw Double pole Double pole Equivalent to two SPSTswitches controlled
by a single mechanism
DPDT
Double pole, double throw Equivalent to two SPDT switches controlled by a single mechanism:
A is connected to B and D to E, or A is connected to C and D to F.
http://en.wikipedia.org/wiki/Electronicshttp://en.wikipedia.org/wiki/Electronicshttp://en.wikipedia.org/wiki/Electronicshttp://en.wikipedia.org/wiki/Electrical_componenthttp://en.wikipedia.org/wiki/Electrical_componenthttp://en.wikipedia.org/wiki/Electrical_componenthttp://en.wikipedia.org/wiki/Electrical_circuithttp://en.wikipedia.org/wiki/Electrical_circuithttp://en.wikipedia.org/wiki/Electrical_circuithttp://en.wikipedia.org/wiki/Electric_currenthttp://en.wikipedia.org/wiki/Electric_currenthttp://en.wikipedia.org/wiki/Electric_currenthttp://en.wikipedia.org/wiki/Insulator_%28electric%29http://en.wikipedia.org/wiki/Insulator_%28electric%29http://en.wikipedia.org/wiki/Insulator_%28electric%29http://en.wikipedia.org/wiki/Light_switchhttp://en.wikipedia.org/wiki/File:DPST-symbol.svghttp://en.wikipedia.org/wiki/File:SPDT-Switch.svghttp://en.wikipedia.org/wiki/File:SPST-Switch.svghttp://en.wikipedia.org/wiki/File:DPST-symbol.svghttp://en.wikipedia.org/wiki/File:SPDT-Switch.svghttp://en.wikipedia.org/wiki/File:SPST-Switch.svghttp://en.wikipedia.org/wiki/File:DPST-symbol.svghttp://en.wikipedia.org/wiki/File:SPDT-Switch.svghttp://en.wikipedia.org/wiki/File:SPST-Switch.svghttp://en.wikipedia.org/wiki/Light_switchhttp://en.wikipedia.org/wiki/Insulator_%28electric%29http://en.wikipedia.org/wiki/Electric_currenthttp://en.wikipedia.org/wiki/Electrical_circuithttp://en.wikipedia.org/wiki/Electrical_componenthttp://en.wikipedia.org/wiki/Electronics7/31/2019 0.Basic Engineering Practice Electrical and Electronics Lab
7/18
The Starter
The traditional starter consists of a small bulb containing a gas (usually argon) and a bi-metal
contact. When power is first applied to the fixture and is unable to flow through the fluorescent
lamp, a small amount of electricity arcs through the argon gas in the starter bulb. Because of
where the starter is wired into the electrical circuit, when current flows through the starter, it also
flows through the lamp.As current continues to flow through gas in the starter, the gas in thestarter heats and starts to bend one of the metal contacts inside, in the same way that a bi-metal
thermostat works. When sufficiently heated, the bi-metal moves out of position and creates a
direct electrical circuit in the starter. Now, the maximum amount of current flows through the
filaments of the fluorescent lamp, which heats the gas in the fluorescent lamp.
Choke:
A choke ballast is a device chokeintended to limit the amount of current in an electric circuit.
Fluorescent lamps require a ballast to stabilize the current through the lamp, and to provide the
initial striking voltage required to start the arc discharge. The Ballast handles the job of makingsure that each lamp can only draw a certain amount of electricity no matter how hot the gas is.As
to the current-limiting function of the ballast, they only come in two types: Magnetic and
Electronic.
Magnetic (sometimes called Inductive) ballasts contain an electrical choke, which is a specially
wound coil of wire. Since electrical current flowing through a wire generates a changing
magnetic field around the wire, and a changing magnetic field generates electrical current in
wires within that magnetic field, a ballast uses these opposing magnetic forces to limit the
amount of electrical current that can pass through the coils inside. As the current flow through
the ballast increases, the coils inside the ballast generate a stronger magnetic field that opposesthe flow of current that is trying to pass through the ballast to the lamps. This interaction
achieves a balance and limits the total current flow to the lamps to a specific amperage. 100 or
120 pulses per second produced by a magnetic ballast. Magnetic ballasts have been around since
fluorescent lighting was invented, which was around 1935.
http://en.wikipedia.org/wiki/File:DPDT-symbol.svg7/31/2019 0.Basic Engineering Practice Electrical and Electronics Lab
8/18
Insulators:Electrical wiring in general refers to insulatedconductorsused to carryelectricity,and associated devicesA true insulator is a material that does not respond to an electric field andcompletely resists the flow ofelectric charge. Some materials such asglass,paperorTeflonare
very good electrical insulators.
Zener diode
A Zener diode is a special kind ofdiodewhich allows current to flow in the forward direction
same as an ideal diode, but will also permit it to flow in the reverse direction when the voltage is
above a certain value known as thebreakdown voltage,
http://en.wikipedia.org/wiki/Conductor_%28material%29http://en.wikipedia.org/wiki/Conductor_%28material%29http://en.wikipedia.org/wiki/Conductor_%28material%29http://en.wikipedia.org/wiki/Electricityhttp://en.wikipedia.org/wiki/Electricityhttp://en.wikipedia.org/wiki/Electricityhttp://en.wikipedia.org/wiki/Electric_chargehttp://en.wikipedia.org/wiki/Electric_chargehttp://en.wikipedia.org/wiki/Electric_chargehttp://en.wikipedia.org/wiki/Glasshttp://en.wikipedia.org/wiki/Glasshttp://en.wikipedia.org/wiki/Glasshttp://en.wikipedia.org/wiki/Electrical_insulation_paperhttp://en.wikipedia.org/wiki/Electrical_insulation_paperhttp://en.wikipedia.org/wiki/Electrical_insulation_paperhttp://en.wikipedia.org/wiki/Polytetrafluoroethylenehttp://en.wikipedia.org/wiki/Polytetrafluoroethylenehttp://en.wikipedia.org/wiki/Polytetrafluoroethylenehttp://en.wikipedia.org/wiki/Diodehttp://en.wikipedia.org/wiki/Diodehttp://en.wikipedia.org/wiki/Diodehttp://en.wikipedia.org/wiki/Breakdown_voltagehttp://en.wikipedia.org/wiki/Breakdown_voltagehttp://en.wikipedia.org/wiki/Breakdown_voltagehttp://en.wikipedia.org/wiki/Breakdown_voltagehttp://en.wikipedia.org/wiki/Diodehttp://en.wikipedia.org/wiki/Polytetrafluoroethylenehttp://en.wikipedia.org/wiki/Electrical_insulation_paperhttp://en.wikipedia.org/wiki/Glasshttp://en.wikipedia.org/wiki/Electric_chargehttp://en.wikipedia.org/wiki/Electricityhttp://en.wikipedia.org/wiki/Conductor_%28material%297/31/2019 0.Basic Engineering Practice Electrical and Electronics Lab
9/18
FLUORESCENT LAMP WIRING
Expt.No: Date:
AIM:To make wiring for fluorescent lamp with switch control and test it.
MATERIALS REQUIRED:
S.No Name of the Component Range / Type Quantity
1Fluorescent lamp fixture 4 ft
1 No
2 Fluorescent lamp 40W/240V 1 No
3 Choke 40W, 230V, 1 No
4 Starter 1 No
5 Switch 1 No
6 Wires 1/18As per
requirement
TOOLS REQUIRED:
S.No Name of the tools Quantity
1 Screw driver 1 No
2 Wire Cutter 1 No
3 Tester 1 No
PRECAUTIONS:
Check the connections thoroughly before switching ON the supply. Handle the lamp safely. Be careful while handling the tools.
7/31/2019 0.Basic Engineering Practice Electrical and Electronics Lab
10/18
CIRCUIT DIAGRAM
THEORY:
Fluorescent lamp relies on fluorescence. Fluorescence is the emission of light by asubstance that has absorbed light or other electromagnetic radiation of a different wavelength. It is a form
of luminescence. The most striking examples of fluorescence occur when the absorbed radiation is in the
ultraviolet region of the spectrum, and thus invisible to the human eye and the emitted light is in the
visible region.
CONSTRUCTION OF FLUORESCENT LAMP:
The basic elements in the fluorescent lamp are bulb, electrodes, gases, base, starter and
choke. The lamp is a glass tube with two electrodes, one at each end. Electrodes are coiled tungsten wires
coated with an emission material. Inside the glass tube is a partial vacuum and a small amount of mercury
vapor and argon, xenon, neon, or krypton. The inner surface of the bulb is coated with a fluorescentcoating made of varying blends of metallic and rare-earth phosphor salts. When heated the electrodes emit
electrons. These electrons when it bombards with mercury atoms produce ultraviolet rays. The
phosphorus salts convert the ultraviolet rays to visible light. The traditional starter consists of a small bulb
containing a gas (usually argon) and a bi-metal contact. choke ballast is a device chokeintended to limit
the amount of current in an electric circuit.
1 AC
230V,
50Hz,
S
CHOKE
STARTER
Fluorescent lamp assembling circuit
P - Phase
N - Neutral
S -switch
Fluorescent lamp
7/31/2019 0.Basic Engineering Practice Electrical and Electronics Lab
11/18
WORKING
Step 1: When power is first applied, the resistance of the cold fluorescent lamp prevents the electricity
from flowing through it. Instead, a small amount of electricity arcs through the gas in the starter bulb, also
called the starter bottle. Although current is now flowing through both filaments of the fluorescent lamp,
the current flow is too low to illuminate the starter filaments or generate any heat to start the fluorescent
lamp, but the current flow is enough to heat the starter bulb gas.
Step 2: As the starter bulb heats, a bi-metal plate inside the starter begins to bend until it makes contact
with the other contact. This causes the entire starter assembly to have no resistance to the electrical flow,
and now the full line voltage flows through the fluorescent lamp filaments, quickly heating the gas in the
ends of the fluorescent lamp.
Step 3: Since the gas in the starter is no longer being heated, it now begins to cool. Meanwhile, the full
line current is flowing through the starting filaments in the fluorescent lamp, heating the gas in that lamp.
After a few seconds, the starter cools sufficiently that the bi-metal contact starts moving back to its "cold"
position, breaking the short circuit. The electricity now has no direct path through which to flow, and
seeks the next lowest path of resistance. If the gas in the fluorescent lamp is sufficiently heated, theelectricity will now arc through the fluorescent lamp.
STEP 4: When a flow of electrical current passes through argon gas, and mercury vapor, ultraviolet light
is produced. This ultraviolet light strikes a layer of phosphor that is coated on the inside of the fluorescentlamp, and in turn the phosphor blocks most of the ultraviolet light. Because of the ultraviolet light, the
phosphor emits various frequencies of visible light. this process not only begins the generation of light,
continues to heat the gas in the fluorescent lamp.
Step 5: The ballast now begins its task of limiting how much current can safely flow through the
fluorescent lamp Up until now, so little current was drawn that the ballast did not have to do anything but
now the current increases, because as the gases get hot their resistances decrease leading more current
flow and further decrease in resistance which is called negative resistance.
PROCEDURE:
1. Give the connections as per the circuit diagram shown in figure.2. Fix lamp and the choke in the tube holder.3. The phase wire is connected to the choke through the switch and neutral directly to the tube.4. Connect the starter in series with the tube.5. Test the working of the lamp by giving electric supply to the circuit.
RESULT:Thus the fluorescent lamp was assembled and tested.
7/31/2019 0.Basic Engineering Practice Electrical and Electronics Lab
12/18
STAIR CASE WIRING
Expt.No: Date:
Aim:
To control the status of the given lamp by using twoway switches
MATERIALS REQUIRED:
S.No Name of the apparatus Range Quantity
1 Incandescent Lamp 40W 1No
2 Lamp Holder 1 No
3 Two Way Switch 230V,5A 2No
4 Wires As reqd.,
TOOLS REQUIRED:
S.No Name of the tools Quantity
1 Screw driver 1 No
2 Wire Cutter 1 No
3 Tester 1 No
PRECAUTIONS:
Check the connections thoroughly before switching ON the supply. Handle the lamp safely. Be careful while handling the tools.
7/31/2019 0.Basic Engineering Practice Electrical and Electronics Lab
13/18
CIRCUITDIAGRAM:
Operation of the switches:
Position Of Switch (S1) Position of Switch (S2) Condition of Lamp
A B ON
B B OFF
B A ON
A A OFF
THEORY:
The stair case wiring is used to control a lamp (for example to lighten the stairs) from
two different places (say up and down the stairs) here two numbers of 2-way switches are used
as shown in the circuit. Let switch S1 be down the stairs and switch S2 up the stairs. Initially let
S1 be in position B and S2in position A. The lamp does not glow as the circuit is not closed.
Now a person can switch on the lamp from below the stairs by moving S1 from B to A. After
reaching upstairs he can switch the lamp off by moving S2 from position A to B. The table
explains the operation of the circuit clearly.
S1 S2
B
AA
B
2 way switch
P
N
1
230V AC
50 Hz
Lamp, 40W
7/31/2019 0.Basic Engineering Practice Electrical and Electronics Lab
14/18
PROCEDURE:
1. Place the accessories as per the circuit diagram.2. Take one wire connect one end to the phase side and other end to the middle point
of SPDT switch 1
3. Upper point of SPDT switch 1 is connected to the lower point of SPDT switch2.4. Lower point of SPDT 1 is connected to the upper point SPDT switch2.5. Another wire taken through a P.V.C pipe and middle point of SPDT switch 2
is connected to one end of the lamp holder.
6. Another end of lamp holder is connected to neutral line.7. Circuit is tested for all possible combination of switch position.
RESULT:
The stair case wiring is performed and tested for satisfactory working.
7/31/2019 0.Basic Engineering Practice Electrical and Electronics Lab
15/18
MEASUREMENT OF ELECTRICAL QUANTITIES VOLTAGE, CURRENT, POWER
& POWER FACTOR USING RLC CIRCUIT.
Expt.No: Date:
AIM:
To measure voltage, current, power and power factor in a single phase AC circuit
using wattmeter by RLC loading.
MATERIALS REQUIRED:
S.No Name of the apparatus Range Quantity
1 Single Phase Autotransformer 230V/(0-270)V,18A 1 No
2 Single Phase energy meter 300V,10A, LPF 1 No
3 Voltmeter (0-300V) MI 1 No
4 Ammeter (0-10A) MI 1 No
5 RLC Load 5kW 1 No
6 Connecting wires As reqd.,
TOOLS REQUIRED:
S.No Name of the tools Quantity
1 Screw driver 1 No
2 Wire Cutter 1 No
3 Tester 1 No
PRECAUTIONS:
Check the connections thoroughly before switching ON the supply. Handle the instruments carefully. Be careful while handling the tools.
7/31/2019 0.Basic Engineering Practice Electrical and Electronics Lab
16/18
CIRCUIT DIAGRAM
THEORY:
Power in an electric circuit can be measured using a wattmeter. A wattmeter
consists of two coils, namely current coil and pressure coil or potential coil. The current
coil is marked as ML and pressure coil is marked as CV. The current coil measure the
quantity that is proportional to the current in the circuit the pressure coil measures quantity
that is proportional to the voltage in the circuit.
The given wattmeter is loaded by direct loading. The ammeter is connected in
series to the wattmeter. Since the same current flows in both the coils, the current and
voltage across the circuit are constant. The power consumed by the load is measured using
the wattmeter and calculated using the relation given below.
Power = V x I Cos
Power factor = W/ (V x I)
7/31/2019 0.Basic Engineering Practice Electrical and Electronics Lab
17/18
FORMULA
Actual power = W x Multiplication factor
Where W Observed wattmeter reading
Apparent power = VI watts
Where V Voltmeter reading
I Ammeter reading
Power Factor, cos = Actual Power / Apparent Power
PROCEDURE:
1. Connect the circuit as shown in the circuit diagram.2. Initially no load is applied.3. Autotransformer is set to minimum voltage position before switching on the power
supply.
4. Set the rated voltage by using the autotransformer. Measure and record the values ofvoltmeter, ammeter and wattmeter on no load condition. Also carefully note the
multiplication factor of the wattmeter that is mentioned in the wattmeter itself.
5. Apply the load by adjusting RLC load.6. Measure and record the values of voltmeter, ammeter and wattmeter.7. Repeat the steps 5 and 6 until the ammeter reading reaches 10A.8. After taking all the readings, reduce the load slowly to the minimum and bring the
voltage to minimum in the autotransformer. Switch off the power supply.
9. Calculated the Indicated power by the given formula.10.Calculate the power factor by the given formula.
7/31/2019 0.Basic Engineering Practice Electrical and Electronics Lab
18/18
OBSERVATION TABLE:
Multiplication Factor=
S.No
Voltage
(V)
Current
(I)
Wattmeter Reading
(W)
Actual power
(W)
Power factor
Cos
observed Actual
1
2
3
4
5
MODEL GRAPH (RESISTIVE LOAD):
RESULT:
Thus the electrical quantities voltage, current, power and power factor in a single phase
AC circuit is measured using wattmeter by RLC loading.
Voltage Vs power factorVoltage Vs Current Voltage Vs Power
I
PFP
V
V V