EXPERIMENT No. :-1 AIM:- APPARATUS: -LVDT kit, Multimeter

DEPARTMENT OF ECE EMI LAB (EE-323-E) 1

EXPERIMENT No. :-1AIM:-To measure output voltage w.r.t the displacement of the core on the LVDT kit andfind the graphical relationship between the two.

APPARATUS: - LVDT kit, Multimeter

THEORY: - LVDT is basically a mutual inductance type transformer with variablecoupling between the primary and two secondary coils. It is equivalent to E.Pick off in itsoperation except the reluctance of magnetic path is mostly due to air path. Uniformlywound over a certain length of transducer and two identical secondary coil systematicallywound on either side of the primary coils and away from center. The iron rod is free tomove inside the coil in either direction from the null point when primary coil is excitedlyAC supply the induced emf of secondary are equal to each other with the core lying innull position. The secondary are connected in series with but in phase opposition so thatresultant output voltage is zero.Displacement of core in either direction from the nullposition results in output voltage as read by an AC rms voltmeter and it is observed thatthere is a residual voltage at the null position. Due to capacitance coupling betweenprimary and secondary and the characteristics of a linear over a limited displacement.

DIAGRAM:


CIRCUIT DIAGRAM

PROCEDURE: -I. Connect the multimeter at the output of kit..2. Set the range to a maximum value of 10 mm.3. More the gauge from zero to maximum of 20mm.4. Value and note the corresponding values of voltages in themultimeter.5. Plot the graph between displacement and voltages on thegraph paper.

OBSERVATION TABLE


PRECAUTION: -1. The values on the multimeter should be carefully noted.2. The core should be set to a maximum value of 20mm.3. To get the good performance from the kit, main roomtemperature.4. To check the power supply, it should be 220+!- 10% 50Hz toavoid voltage hazard.RESULT: - LVDT was studied well and graph of displacement was linear for aparticular range.


EXPERIMENT 2

OBJECTIVES : To study capacitive transducerREQUIREMENT: Capacitive transducer kit, multimeter

DIAGRAM

THEORY : The principal of operation of capacitive transducer is based upon familiareducation for capacitance of a parallel plate capacitor.

C = єA /DC = є 0 є r A/D

Where A = overlapping area of platesd =distance between platesє r = relative permittivityє 0 = permittivity of free space

The capacitive transducer works on the principle of change of capacitance which maybe caused by

1 Change of area..2 change in distance between plates3 change in dielectric constant

The capacitance may be measuredwith bridge circuit. The output impedence of capacitivetransducer isXc =2πfcWhereC = capacitanceF =frequencyCapacitance is maximum when two plates completely overlap each other ie whenΘ = 180 degree


PROCEDURE:

1 Turn on the power supply.2 Change the angle step by step.3 Using multimetre take corresponding voltage values.4 Note down the readings for voltage and angles.5 Plot the graph between Angie Vs Voltage.


EXPERIMENT 3

Aim: -To study the use of load cell for measurement.Apparatus: - load transducers kit ,load, multimeterTheory:-load cells are the transducers in which load is used as primary transducer &the strain gauges are used as secondary transducers .when strain gauges are employed formeasuring strain either ring type or column type elements & then compressive or tensilestress are calculated.Procedure: -1)first connect the load cell at a pin connector of transducer bridge.2)power ON the switch to give supply to the instrument.3)give sometime to stabilize the instrument.4)set the gain of load cell by “SPAN” turn trim pot.Precautions: -1)to get good performance from the tutor room temp. must be maintained.2)note down the reading carefully & move the scale slowly for taking readings.3)to check the power source, it should be 230V &50 hz to avoid over voltage hazards.


FUNCTIONAL BLOCK DIAGRAM OF DIGITAL LOAD INDICATOR


EXPERIMENT: 4

AIM:To measure pressure using strain guage.APPARATUS REQUIRED:• Strain measurement kit• Scale• Connecting wiresTHEORY:-When regular bodies are subjected to stress then strain developed can be measuredelectrically and relationship between the forces responsible for the stress of resultingelectrical output signal can be obtained. The resistance strain guage element is one suchdevice that plays the role of secondary transducer is sending the tensile or compressivestrain is a particular at a point on the surface of a body. If the body is known as modulesof electricity E of the material of body, the strain can be measured. the strain guagetransducer depend upon the fact that when the wire is stretched elastically its length anddiameter are altered. This result in overall change of resistance to both the diamentionallychange of resistivity.PROCEDURE:-• Connect the strain cantilever of a pin connector through wire.• Power ON the switch, the Red LED indicates the power available• On instrument.• Give sometimes to stabilize the instrument.• Balance the strain cantilever bridge by SPAN the twintrimpot.• Now apply the weight on the strain cantilever and measure it on the• Display output.• Repeat this to measure different weight on cantilever.

Now find out the strain in the cantilever by applying stress from Calculation

DIAGRAM.


STRAIN GUAGE

PRECAUTIONS:To get good performance from the exp., we have to maintain room temp.To check the power source, it should be 230V, 50hz to avoid overall Voltage hazards.RESULTS:Experiment is performed successfully and observations are noted.


EXPERIMENT NO. 5

AIM: -To study Water Level Indicator

APPARATUS: -

Water level kit, multimeter,water

THEORY:- Water level indicator works just like an LVDT. In LVDT, linearmotion is converted into electrical motion. In water level indicator one level or onerod is fixed and water is moving up and down. So displacement is there as waterlevel rises or falls. It can be converted into electrical signals by kit. Also, voltageis measured by voltmeter.


PROCEDURE:Take water in a jar and connect wires of it to kit.• There is tap in jar to draw water from it.• As the water decrease voltage also decreases.• Take reading of voltmeter, display and scale on bar.PRECAUTION:Take reading carefully.• Connections should be tight and right.’

RESULT :Water level indicator is studied and graph between voltage and scale readingis found to be linear


EXPERIMENT 6

AIM:Measurement of temperature using thermocouple .APPARTUS:Thermometer, thermocouple, sensor, tutor, vessel and water, multimeter and conductingrod.THEORY:Thermocouple is a transducer based on the seeback effect. Jt is most widely used andcommon signal device for temperature measurement in industrial application. For therange of O-400 F. Thermocouple is a self generating transducer and is basically a pair ofdissimilar metal conductors joined so as to produce an emf when the junction are kept atdifferent temperatures and material of conductors. Combination used for base metalthermocouples are

Copper-Constantan (-300F to 600F)Iron-Constantan (-300F to -1500F) etc.Thermocouples are cheap, reliable in service, are easily used, wide. range of temperaturemeasurement and have a very good time of response characteristics(low thermal mass)but they are not perfectly linear over centre range, require cold junction compensation.


OBSERVATION TABLE

PROCEDURE:1. Switch on the power supply of tutor.2. Ensure that the water heater is ready and contains sufficient amount of water.3. Keep the thermocouple in air at room temperature indicator wi!l display roomtemperature at this point, measure the voltage across thermocouple.4. Keep on the thermocouple in water kept on be boiled and measure the voltage and alsotemperature with the help of thermometer, down the display reading.5. By adding the cold water, get the reading of different temperatures of water.

PRECAUTION:1. While connecting the thermocouple to the input terminals, observe correct polarity.2. A broken or unconnected thermocouple will give out of scale reading.

RESULT:.Thermocouple is studied and observations are noted.


EXPERIMENT 7

AIM: -To measure temperature using RTD sensor.APPRATUS: -Thermometer, RTD sensor, heater, vessel, multimeter and conductive metal rod.THEORY : -The principle operation of resistance temperature detect is based on the fact that electricalresistance of many metals increases almost directly with temperature and is reciprocal tohigh degree of accuracy. The term used to express this characteristic is well known ascoefficient of resistance and is defined by formula

Rt =Ro(1 + α t)Where,α =temperature coefficient of resistance.Ro=Resistance of wire at zero degree.Rt’ =Resistance of wire at any temperature.Platinum, Copper, Nickel are used as RTD elements which are further used as transducerfor temperature measurement.1. The resistance of RTD increases as temperature increases.2. Resistance thermometer are larger in size and less convenient to apply thanthermocouple. They are massive & hcnce exhibit poor time response characteristics.3. They require bridge balance circuitry and hence rather restricted upper temperaturerange.4. They require higher accuracy, reliability than thermocouple.PROCEDURE -1. Switch ‘ON’ the power supply, the red LED glows on the front panel.2. Give the zero degree Celsius temperature of RTD by keeping it with ice. Adjust thezero on the display by adjusting through potentiometer.3. Keeping the RTD into the boiling water and adjust display reading to 100 by adjustingthrough span potential.4. Keep the RTD in air at room temperature. The indicator will display room temperature.Calculate the resistance of RID with the help of multimeter.5. By keeping the RID in the heater at different temperature, note down the displaytemperature.PRECAUTIONS :1. Maintain the room temperature.2. The environment would be dust proof and humidity proof.RESULT :

The experiment was performed successfully and the observations are noted.


OBSERVATION TABLE


EXPERIMENT 8

AIM:-To study long range linear measurement using potentiometer sensor.Apparatus:-Measurement kit, multimeter scale.Theory:-A sensitive potentiometer used for the purpose of voltage division ,consist of a sensitiveelement provided with a sliding contact may be translating or rational. The sensitiveelement of the potentiometer may be excited by either A.C or D.C Voltage .It is a passivetransducer since it requires an external power supply for its operation .In a translatingpotentiometer , the 0/P voltage across varies with the displacement of Wiper.

Let Ei & Eo be the I/P & 0/P voltage resp.Xt = total length of translational potentiometer.Xi = displacement of Wiper from zero positionRp = total resistance of the potentiometerRo/Xt = resistance per unit length0/P voltage is given by = resistance at 0/P * I/P voltage

resistance at I/PEo = Rp(Xi/Xt)Ei

Rp

= (Rp/Xt)*EiRp/Xi

=Xi*Ei/XtProcedure:-l) connect the sensor at the 9pm connector.2) switch “ON” the ON/OFF switch , the RED led on the front panel indicate that poweris available on the instrument.3) Adjust the span range by Span control trim pot. & zero reading by zero control trimpot.4) With the help of multimeter , the DC 0/P volt, is measured as the displacement isvaried.The physical displacement & indicate by the tutor is recorded.Precautions:-l)to get good performance , maintain room temp.2)move the scale carefully & slowly.3) check the power source it should be 230V & 50 hz.Result:- The experiment was performed successfully & the readings were noted down


BLOCK DIAGRAM.


EXPERIMENT 9

AIM: -To study the use of Capacitive Transducer for water level measurement .

APPARATUS: -Capacitive Transducers, water, and multimeter.THEORY: -The Tutor is meant for measurement of water level through water level transducer. TheTutor is very useful for study of water level sensor. The circuit diagram is given on thetop cover on the tutor to understand the measurement parameter at a glance. All thedifferent test points are also provided on top cover with giving there headings to facilitatethe student to understand without any operation 1instruction by any third person.PROCEDURE: -1. To connect the water level sensor at the 9 pin connector.2. Switch ‘ON’ the ON/OFF switch and see the power indicator. The RED LED on thefront panel will glow.3. Keep the sensor in the water vessel or tank, which is supplied with this instrument.Keep the water level in the vessel or tank at zero position.4. Adjust the zero reading on the display by zero control trimpot.5. Adjust the span range by Span Control trimpot.6. For example:The water level in the tank should be at 0 point, as per scale is provided on this tank.Then to supply the water through inlet point in the tank. Then to adjust the displayreading at zero point through zero trimpot. The capacity of water level sensor is 100mm.The reading will increase through water level sensor on the display according to the waterlevel in the tank. If the display is not at 100mm, you can adjust the water level reading ondisplay through Span trimpot.PRECAUTIONS: -1. To get the good performance from the tutor you have to maintain room temperature.2. To check the power source, it should be 23 0+1-10%, 50 Hz. to avoid over voltagehazards.3. To get best performance, you have to put the instrument at dust proof and humidityfree environment.4. Do not try to open the instrument or repair it .Contact manufacturer in case of any fault/ difficulty.


CAPACITIVE TRANSDUCER


EXPERIMENT 10

AIM:Use of inductive transducer for displacement measurement.

EQUIPMENTS : Inductive transducer kit, multimeter ,water

THEORYINDUCTIVE TRANSDUCER

Inductive transducer are those in which self inductance of a coil or th’ta1 inductance of apair of coil is altered in value to a variation in value of the quantity under measurement.Transducers based on the above principle are said to possess considerable sensitivity andscope of application, especially for displacement and thickness measurement. Some ofthe general observation regarding the operation and performance of the inductors may berecalled in this context for an appreciation of the limitations that render them somewhatless popular in instrumentation systems .Detection of changes in inductance can be doneby magnetic fields that would interfere with all the neighboring circuits while the coilsthemselves link with the external magnetic fields. The problem becomes more acutewhen the coils are used in high frequency circuits. Proper electric and magnetic shieldingbecomes essential. If the circuits are iron-cored, the magnetic flux contained in the pathof iron and the interference effects are minimized. The frequency of ac supplies used incircuits should be atleast 10 times higher than the frequency of the input quantity. Ironlosses of the cores add to the resistance of the copper of coils and vary With thefrequency of excitation. Inductance variation may not always be brought about variationin resistance. But the looks for output signals to be exclusively functions of changes ininductance.OPERATING PROCEDURE:1. To connect the inductive sensor at the 9 pin connector.2. Switch ‘ON’ the ON/OFF switch and see the power indicator. The RED LED on thefront panel will glow.3. Adjust the zero reading on the display by zero control. Pot.4. Travel 50 mm through scale.5. Adjust the span range by span control pot. Reading 50.0 mm.


OBSERVATIONTABLE

PRECAUTIONSTo get the good performance from the tutor you have to maintain room temperature.To check the power source, it should be 230 V +1- 10%, 50 Hz to avoid over voltagehazards.To get best performance, you have to put theinstrument at dust proof and humidity freeenvironment.Do not try to open the instrument or repair at. Contact manufacturer in case of any fault.

RESULT :The graph plotted between voltage output and displacement is linear


EXPERIMENT 11

Aim:-To measure the speed of DC motor using magnetic pick up.

Apparatus:-voitmeter ,magnetic pick up speed kit

Theory:-there is a magnetic pickup rn/c by which we can increase or decrease the speed ofmotor.in motor there is a metal plate which is placed just above rotor .it counts therotation & displays on magnetic pick up rn/c.it is one of the method of measurement ofspeed of motor.Procedure:1)connect motor with the speed measuring kit.2)connect voltmeter to rnic.3)switch ON the power supply.4)now increase the speed step by step.5)now note down the readings of voltage & speed.Precautions:—l)speed of motor should be increased very slowly.2)note readiis carefully.3)g.raph is plotted carefully.Result:-the speed of motor is measured and it is plotted against the voltage .voltage isvarying indirectly/indirectly & the graph obtained is a straight line with negative slope.


EXPERIMENT 12

AIM: To study the photocell.

REQUIREMENTS:Photo cell , bulb, kit for measuring intensity of light.THEORY:In this type of device the electrical resistance of material wires varies with the amount ofthe light energy. Starting it, when the photocell has appropriate light incident on it, itsresistance is low and current is high. When the light is interrupted partially or completelythen the current reduces due to increase in resistance.

Procedure:1) Connect the circuit2) Allow the light to fall on the photocell.3) Note down the readings of intensity of light with different ranges of light.

OBSERVATION TABLE


Result: Photocell is studied and graph between the voltage and intensity of light is foundto be linear.Precautions:(1) Take readings carefully.(2) Connections should be applied in proper way.(3) Photocell should be of suitable material

EXPERIMENT No. :-1 AIM:- APPARATUS: -LVDT kit, Multimeter

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