Ele Lab Manual

LMELE102 & 152 Unified Electrical Science

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LABORATORY MANUAL

ELE102

ELECTRICAL SCIENCE-II


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Table of Contents

S.no. Experiment Name Page no.

1 Inverting and non-inverting amplifiers using IC741. Opamp as summer, integrator and Diffrentiator.

3

2 Counter Design using Flip Flops. 8

3 Use of CRO, Function generator and power supply.

12

4 Realization of MUX and DEMUX. 17

5 Active Filter Design using OPAMPS. 20

6 To plot the speed torque characteristics of a dc motor.

22

7 To start and reverse the direction of an induction motor. To plot the speed torque characteristics of an induction motor.

25

8 Interfacing of microcontroller with dc motor and LED.

27

9 Driving an LED/Relay/motor using 8051 microcontroller output ports.

29

10 To display alpha numeric characters using 8051. 31


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EXPERIMENT-1

Aim: Inverting and non-inverting amplifiers using IC741. Opamp as summer, integrator and Diffrentiator.

Equipment Required: CRO, Power supply, Function generator Material Required: Op-Amp 741, resistor, Bread board, connecting wires.

PIN DIAGRAM 741

CIRCUIT DIAGRAM:-


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R1= 5KΩ, R2= 10kΩ

DESIGN PROCEDURE:-

The gain of inverting amplifier is given by

The gain for non-inverting amplifier is given by

EXPERIMENTAL PROCEDURE:

1. Connect the circuit as shown in Fig.

2. Apply +12V to pin 7 and –12V to pin 4. Connect common terminal of power supply to

ground on the breadboard.

3. Apply a dc voltage of 0.1V to the pin-2 of IC. Measure the output.


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4. Increase voltage in steps of 0.1V up to 1.0V and measure the output.

OBSERVATION TABLE:

S.NO Vi(v) Vo(v) Gain(dB)

a) Inverting Summing Amplifier Figure 2 shows an example of how an operational amplifier is connected to perform voltage summation. In this figure, an ac and a dc voltage are summed. In general,


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b) Difference Amplifier A difference amplifier has two inputs and the output voltage is proportional to the voltage difference of the input voltages. In fact, the (open-loop) Op-Amp itself is a difference amplifier, except that the gain is ideally infinity. Here we want a difference amplifier with finite gain. One such circuit using a single Op-Amp is shown in Figure 4. It can be shown that the gain of the difference amplifier can be calculated using the following:

This equation can be simplified by making R3 = RF = R1 = R2, yielding a simple differential amplifier with unity gain:


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Procedure:

1. Connect the circuit as shown in Fig.

2. Apply +12V to pin 7 and –12V to pin 4. Connect common terminal of power supply to

ground on the breadboard.

3. Apply different voltages to the pin-2 of IC. Measure resultant output.

CONCLUSION: - write down %age error of inverting and non inverting amplifier.


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EXPERIMENT NO.-2

AIM: Counter Design using Flip Flops.

Apparatus Required: -

IC 7408, IC 7476, IC 7400, IC 7432 etc.

Procedure: -

1. Connections are made as per circuit diagram.

2. Clock pulses are applied one by one at the clock I/P and the O/P is

observed at QA, QB & QC for IC 7476.

3. Verify the Truth table .

Circuit Diagram:


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Conclusion:-


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EXPERIMENT 3

Aim: Use of CRO, Function generator and power supply.

Equipment Required: CRO, Probe, Function Generator, Power Supply, Digital Multimeter Material Required: Resistance, Bread Board

CIRCUIT DIAGRAM:-

THEORY:

To achieve the purpose, various controls are provided on front panel of electronic equipment. The operating controls provided on the front panel of instruments are ON/OFF switch, selector switch


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for current, voltage, resistance, range selection switch for frequency, time/div, volt/div, switch for channel selection and control knob for level, focus etc

PROCEDURE:-

1. Observe the given equipment. 2. Draw front panel diagrams of a) Signal generator/ Function generator b) CRO, c) Power

supply d) Digital Multimeter 3. Identify the different operating controls and understand their functions. 4. List the different operating controls and write their functions.

Equipment 1: CRO

OBSERVATIONS: Give a signal of 1V and 1 Hz.

1. Frequency/div: ………………………………………………………..


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2. Volt/div: ……………………………………………………….. 3. Intensity: ……………………………………………………….. 4. Focus: ……………………………………………………….. 5. Square wave testing: ……………………………………………………….. 6. AC/DC/GROUND: ……………………………………………………….. 7. UP/DOWN: ……………………………………………………….. 8. LEFT /RIGHT: ……………………………………………………….. 9. Make: ……………………………………………………….. 10. Model: ……………………………………………………….. Lissajous Figure

In mathematics, a Lissajous curve is the graph of the system of parametric equations

The appearance of the figure is highly sensitive to the ratio a/b

For a ratio of 1, the figure is an ellipse, with special cases including circles (A = B, δ = π/2 radians) and lines (δ = 0). Another simple Lissajous figure is the parabola (a/b = 2, δ = π/2). Other ratios produce more complicated curves, which are closed only if a/b is rational.

Unpress all CRO buttons, especially “component tester”. Connect two signal generators, one to channel I and one to channel II. Switch the CRO to S-Y operations, by pressing in the X-Y operations button.

Connect up one signal generator to the CRO and connect it to channel II using the CRO leads.

This is the frequency applied to the vertical input fy . Connect the other signal generator to the CRO and connect it to channel I using the CRO leads. This is the frequency applied to the horizontal input fx . Note that you can read the frequency from the dial of the signal generator.

input horizontal the toappliedfrequency

input vertical the toappliedfrequency ratio x

y

ff


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Try to generate the following figures. The frequency ratios required to generate them are shown.

Equipment 2: Power supply OBSERVATIONS:

1. Coarse: ……………………………………….………………… 2. Fine: ……………………………………….………………… 3. Voltage range: ……………………………………….………………… 4. Resolution: ……………………………………….………………… 5. Input: ……………………………………….………………… 6. Make: ……………………………………………………….. 7. Model: ………………………………………………………..

Equipment 3: Function generator

OBSERVATIONS:

1. Function selector: ……………………………………………………….. 2. Frequency ranges: ……………………………………………………….. 3. Amplitude: Minimum………………Maximum ……………….. 4. Make: ……………………………………………………….. 5. Model: ………………………………………………………..


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OBSERVATIONS: 1. DC/AC Voltage measurement 2. Resistance measurement

CONCLUSION: - The different operating controls of the equipment are identified.


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EXPERIMENT 4

Aim: Realization & use of MUX and DEMUX. Equipment Required: Digital Trainer Kit Material Required: IC 74153, IC 74139, Connecting wire PROCEDURE: - (IC 74153)

1. The Pin [16] is connected to + Vcc.

2. Pin [8] is connected to ground.

3. The inputs are applied either to ‘A’ input or ‘B’ input.

4. If MUX ‘A’ has to be initialized, Ea is made low and if MUX ‘B’ has to be initialized, Eb

is made low.

5. Based on the selection lines one of the inputs will be selected at the output and thus verify

the truth table

PROCEDURE: - (IC 74139)

1. The inputs are applied to either ‘a’ input or ‘b’ input

2. The demux is activated by making Ea low and Eb low.

3. Verify the truth table.


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CONCLUSION: Truth table of MUX and DEMUX is verified.


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EXPERIMENT 5

Aim: Active filter design using op amp with PSPICE simulation software.

Electronic filters are electronic circuits which perform signal processing functions, specifically to remove unwanted frequency components from the signal, to enhance wanted ones, or both.

Active filters are implemented using a combination of passive and active (amplifying) components, and require an outside power source. Operational amplifiers are frequently used in active filter designs. These can have high Q, and can achieve resonance without the use of inductors. However, their upper frequency limit is limited by the bandwidth of the amplifiers used.

Low Pass Filter

Procedure: 1. Open a new file in Multisim 9. 2. Draw the following Circuit. 3. Do the AC analysis of given circuit and observe the output at node 6 for frequency

range 1 Hz to 100 Khz. 4. Plot the graph of gain with respect to frequency

High Pass Filter


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Procedure: 1. Open a new file in Multisim 9. 2. Draw the following Circuit. 3. Do the AC analysis of given circuit and observe the output at node 6 for frequency

range 1 Hz to 100 Khz. 4. Plot the graph of gain with respect to frequency.


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EXPERIMENT -6

AIM: To plot the speed torque characteristics of a dc motor.

Apparatus Required: DC motor, power supply, connecting wires

Introduction: The dc motor is a highly versatile machine. It has superior torque and speed range capabilities as compared to induction motors driven from constant frequency supply. It is capable of quick reversal, and speed control over a wide range is achieved relatively easily. For this reason they are selected for use in applications requiring these characteristics, such as rolling mills, power shovels and railroad locomotives.

Motor Equations:

Unlike a step motor, the DC brush motor exhibits simple relationships between current, voltage, torque and speed. It is therefore worth examining these relationships as an aid to the application of brush motors.

The application of a constant voltage to the terminals of a motor will result in its accelerating to attain a steady final speed (n). Under these conditions, the voltage (V) applied to the motor is opposed by the back emf (nKE) and the resultant

voltage drives the motor current (I) through the motor armature and brush resistance (Rs).

The equivalent circuit of a DC motor is shown in Fig.


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PROCEDURE:

1. Using a voltage supply set to 9 volts, run the motor unloaded. 2. Measure the rotational speed using a non-contacting tachometer. 3. Measure the motor current under this no-load condition. 4. Using an adjustable torque load such as a small particle brake coupled to

the motor shaft, increase the torque load to the motor just to the point where stall occurs.

5. It is also useful at this point to measure the terminal resistance of the motor. Measure the resistance by contacting the motor terminals. Then spin the motor shaft and take another measurement.

Now we have measured the:

• n0= no-load speed • I0= no-load current • MH= stall torque • R= terminal resistance


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Speed-Torque Graph:

Construct a table of the motor efficiency at various points from no-load to stall torque. The voltage applied to the motor is given, and the current at various levels of torque has been plotted. The product of the motor current and the applied voltage is the power input to the motor. At each point selected for calculation, the efficiency of the motor is the mechanical power output divided by the electrical power input.

TORQUE SPEED CURRENT POWER EFFICIENCY

(oz-in) (rpm) (mA) (Watts) (%)

Plot the graph between the various values of Speed and torque, by considering all the varing factors.


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EXPERIMENT - 7

AIM: To start and reverse the direction of an induction motor. To plot the speed torque characteristics of an induction motor.

Apparatus Required: Induction motor, Power supply, connecting wires

Introduction: AC induction motors are the most common motors used in industrial motion control systems, as well as in main powered home appliances. Simple and rugged design, low-cost, low maintenance and direct connection to an AC power source are the main advantages of AC induction motors.

Fig. shows the Ckt. Dia. Using an INDUCTION MOTOR

Torque speed characteristic

Torque speed characteristic of a motor is important from the point of view of its applications to specific situations. Here in the following equations, we can see by considering a no. of factors we can calculate the torque of the induction motor easily.


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PROCEDURE

1. Connect the circuit as per the circuit diagram. 2. Observing precautions, close the TPST switch. 3. Apply the rated voltage to the stator windings of 3φ induction motor with the help of

3-phase auto transformer. 4. Note down the readings of all meters on no-load. 5. Load the induction motor in steps using the brake-drum arrangement. At each step note

down the readings of all meters up to full load of the motor. 6. Gradually release the load and switch OFF the supply.

S.no. Voltage V (volts)

Current I (Amps)

Speed N (rpm)

Torque N-m

Speed-Torque Graph:

Plot the graph between the various values of Speed and torque, by considering all the varing factors.

Precautions: a) There should not be loose and wrong connections in the circuit. b) Three phase auto transformer should be in minimum output voltage position. c) Initially there should be no load on the motor.

d)Before making or breaking the circuit, supply must be switched OFF.


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EXPERIMENT NO.: 8

AIM: Interfacing of microcontroller with dc motor.

Apparatus Required: 8051 microcontroller kit, IC L293D, dc motor, Connecting wires.


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PROGRAM CODE: L293D_A equ P2.0 ;L293D A - Positive of Motor L293D_B equ P2.1 ;L293D B - Negative of Motor L293D_E equ P2.2 ;L293D E - Enable pin of IC org 0H Main: acall rotate_f ;Rotate motor forward acall delay ;Let the motor rotate acall break ;Stop the motor acall delay ;Wait for some time acall rotate_b ;Rotate motor backward acall delay ;Let the motor rotate acall break ;Stop the motor acall delay ;Wait for some time sjmp Main ;Do this in loop rotate_f: setb L293D_A ;Make Positive of motor 1 clr L293D_B ;Make negative of motor 0 setb L293D_E ;Enable to run the motor ret ;Return from routine rotate_b: clr L293D_A ;Make positive of motor 0 setb L293D_B ;Make negative of motor 1 setb L293D_E ;Enable to run the motor ret ;Return from routine break: clr L293D_A ;Make Positive of motor 0 clr L293D_B ;Make negative of motor 0 clr L293D_E ;Disable the o/p ret ;Return from routine delay: ;Some Delay mov r7,#20H back: mov r6,#FFH back1: mov r5,#FFH here: djnz r5, here djnz r6, back1 djnz r7, back ret


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EXPERIMENT: 9

AIM: Driving an LED/Relay/motor using 8051 microcontroller output ports.

Apparatus Required: 8051 microcontroller kit, LED, Connecting wires.

Operation:

The figure given below shows how to interface the LED to 8051 microcontroller. As you can see the Anode is connected through a resistor to Vcc & the Cathode is connected to the Microcontroller pin. So when the Port Pin is HIGH the LED is OFF & when the Port Pin is LOW the LED is turned ON.

Flashing LED ALGORITHM:

1. Start.

2. Turn ON LED.

3. Wait for some time (delay).


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4. Turn OFF LED.

5. Wait for some time (delay).

6. Go To 2.

PROGRAM 1

1. ORG 0000h

2. loop:

3. CLR P2.0 //Turn ON LED

4. CALL DELAY

5. SETB P2.0 //Turn OFF LED

6. CALL DELAY

7. JMP loop


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EXPERIMENT-10

AIM: To display alpha numeric characters using 8051 microcontroller.

APPARATUS REQUIRED: 8051 microcontroller kit,7-segment LED,Connecting wires

CIRCUIT DIAGRAM:


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PROGRAM CODE:


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