Lab Manual_Basic Electronics

8/10/2019 Lab Manual_Basic Electronics

1/56

Navrachana University Basic Electronics

Navrachana University 1

MECHANICAL ENGINEERING

BASIC ELECTRONICSLaboratory Manual

B. Tech. 4 th Semester (MECH)

Mechanical EngineeringSchool of Engineering and Technology

Navrachana UniversityVadodara


2/56


3/56




NAVRACHANA UNIVERSITY

SCHOOL OF ENGINEERING AND TECHNOLOGY

OF


CERTIFICATE

This is to certify that Mr./Ms.____________________________________________ of B.Tech 3rd Semester

(Mechanical Engineering), Enroll No. _____________ has been found satisfactory in the continuous

Internal Evaluation of Laboratory in the Basic Electronics Laboratory for the Academic year

_________-_________.

Date: ________________________________

Course In-charge

Vadodara.


4/56


5/56




INDEX

Exp.No.

Date of Exp. Aim of Experiment PageNo.

Date ofSubmission

Grade/Marks

FacultySignature

1

2

3

4

5

6

7

8

9

10


6/56




EXPERIMENT NO: 01

P-N JUNCTION DIODE CHARACTERISTICS

AIM:1. To observe and draw the Forward and Reverse bias V-I Characteristics of a P-N

Junction diode.2. To calculate static and dynamic resistance in forward and reverse Bias Conditions.

APPARATUS:

Bread board, connecting wires

THEORY:

A P-N junction diode conducts only in one direction. The V-I characteristics of the diode are curve between

voltage across the diode and current flowing through the diode. When external voltage is zero, circuit isopen and the potential barrier does not allow the current to flow. Therefore, the circuit current is zero.When P-type (Anode) is connected to +ve terminal and n- type (cathode) is connected to ve terminal ofthe supply voltage is known as forward bias.

The potential barrier is reduced when diode is in the forward biased condition. At some forward voltage,the potential barrier altogether eliminated and current starts flowing through the diode and also in thecircuit. Then diode is said to be in ON state. The current increases with increasing forward voltage.

When N-type (cathode) is connected to +ve terminal and P-type (Anode) is connected ve terminal of the

supply voltage is known as reverse bias and the potential barrier across the junction increases. Therefore,the junction resistance becomes very high and a very small current (reverse saturation current) flows inthe circuit. Then diode is said to be in OFF state. The reverse bias current is due to minority charge carriers.

1. P-N Diode IN4007 - 1 No.2. Regulated Power supply (0-30V) - 1 No.3. Resistor 1K - 1 No.4. Ammeter (0-20 mA) - 1 No5. Ammeter (0-200A) - 1 No.6. Voltmeter (0-20V) - 2 No.


7/56




CIRCUIT DIAGRAM:

A) Forward bias:

B) Reverse Bias:

EXPECTED GRAPH:


8/56




OBSERVATIONS:

A) FORWARD BIAS:

S.NO. AppliedVoltage(V) ForwardVoltage(V f ) ForwardCurrent(I f (mA))

B) REVERSE BIAS:

S.NO. AppliedVoltage(V)Reverse

Voltage(V R)Reverse

Current(I R(A))

CALCULATIONS: Calculation of Static and Dynamic Resistance for a given diode.

In forward bias condition:

Static Resistance, R S = Vf / I f =

Dynamic Resistance, R d = Vf / I f =

In reverse bias condition:

Static Resistance, R S = VR/ I R =

Dynamic Resistance, R d = VR / I R =


9/56




PROCEDURE: A) FORWARD BIAS:

1. Connections are made as per the circuit diagram.2. For forward bias, the RPS +ve is connected to the anode of the diode and RPS ve is

connected to the cathode of the diode3. Switch on the power supply and increase the input voltage (supply voltage) in steps of 0.1V4. Note down the corresponding current flowing through the diode and voltage across the

diode for each and every step of the input voltage.5. The reading of voltage and current are tabulated.6. Graph is plotted between voltage (Vf) on X-axis and current (If) on Y-axis.

B) REVERSE BIAS:

1. Connections are made as per the circuit diagram

2.

For reverse bias, the RPS +ve is connected to the cathode of the diode and RPSve is connected to the anode of the diode.3. Switch on the power supply and increase the input voltage (supply voltage) in

steps of 1V.4. Note down the corresponding current flowing through the diode voltage across the diode

for each and every step of the input voltage.5. The readings of voltage and current are tabulated.6. Graph is plotted between voltage (V R) on X-axis and current (I R) on Y-axis.

PRECAUTIONS:

1. All the connections should be correct.2. Parallax error should be avoided while taking the readings from the Analog meters.

CONCLUSION:


10/56





11/56




EXPERIMENT NO: 03

CHARACTERISTICS OF ZENER DIODE

AIM: To study the characteristics and to determine the breakdown voltage of a Zener diode. APPARATUS:

1. R.P.S (0 30) v : 1 No2. Ammeter (0 100) A : 1 No 3. Voltmeter (0 30) v : 1 No4. Zener diode (7.5V) : 1 No5. Resistor (1 K ) : 1 No6. Breadboard : 1 No

THEORY: A properly doped crystal diode, which has a sharp breakdown voltage, is known as Zener diode.

FORWARD BIAS: On forward biasing, initially no current flows due to barrier potential. As the applied potential

increases, it exceeds the barrier potential at one value and the charge carriers gain sufficient energy tocross the potential barrier and enter the other region. the holes ,which are majority carriers in p-region,become minority carriers on entering the N-regions and electrons, which are the majority carriers in the N-regions become minority carriers on entering the P-region. This injection of minority carriers resultscurrent, opposite to the direction of electron movement.

REVERSE BIAS : When the reverse bias is applied due to majority carriers small amount of current (i.e.) reverse

saturation current flows across the junction. As the reverse bias is increased to breakdown voltage, suddenrise in current takes place due to Zener effect.

ZENER EFFECT: Normally, PN junction of Zener Diode is heavily doped. Due to heavy doping the depletion layer will

be narrow. When the reverse bias is increased the potential across the depletion layer is more. This exerts aforce on the electrons in the outermost shell. Because of this force the electrons are pulled away from theparent nuclei and become free electrons. This ionization, which occurs due to electrostatic force ofattraction, is known as Zener effect. It results in large number of free carriers, which in turn increases thereverse saturation current.

PROCEDURE:

FORWARD BIAS :

1. Connect the circuit as per the circuit diagram.


12/56




2. Vary the power supply in such a way that the readings are taken in steps of 0.1V.3. Note down the corresponding ammeter readings.4. Plot the graph: Vf (vs) If.5. Find the dynamic resistance r = V / I .

REVERSE BIAS:

1. Connect the circuit as per the diagram.2. Vary the power supply in such a way that the readings are taken in steps of 0.5V.3. Note down the corresponding Ammeter readings I r.4. Plot a graph between V r & Ir 5. Find the dynamic resistance r = V / I.

CIRCUIT DIAGRAM:

FORWARD BIAS: (0-100)A

1K + -

+ +

(0-30) (0-1) V

- -

REVERSE BIAS:

(0-30)mA

1K + -

+

(0-30) V (0-30) V

- -


13/56




ZENER DIODE CHARACTERISTIC: If (in mA)

I2

VB I1

Vr V1 V2 Vf

(in volts) (in volts)

Ir (in mA)

OBSERVATION TABLE:

FORWARD BIAS:

S.NO. AppliedVoltage(V)

ForwardVoltage(V f )

ForwardCurrent(I f (mA))

REVERSE BIAS:

S.NO. AppliedVoltage(V)Reverse

Voltage(V f )Reverse

Current(I f (A))


14/56


15/56





16/56





17/56


18/56




CIRCUIT DIAGRAM:

EXPECTED GRAPH:

1. INPUT CHARACTERISTICS:

2. OUTPUT CHARACTERSITICS:


19/56


20/56




PROCEDURE:

INPUT CHARACTERISTICS

1. Connect the circuit as per the circuit diagram.2. For plotting the input characteristics the output voltage V CE is kept constant at 1V and for

different values of V BB, note down the values of I B and V BE.

3. Repeat the above step by keeping V CE at 2V and 4V and tabulate all the readings.

4. Plot the graph between V BE and I B for constant V CE.

OUTPUT CHARACTERISTICS:

1. Connect the circuit as per the circuit diagram.2. For plotting the output characteristics the input current I B is kept constant at 50A and for

different values of V CC note down the values of I C and V CE.

3. Repeat the above step by keeping I B at 75 A and 100 A and tabulate the all the readings.

4. Plot the graph between V CE and I C for constant I B.

PRECAUTIONS: 1. The supply voltage should not exceed the rating of the transistor2. Meters should be connected properly according to their polarities

CONCLUSION:


21/56





22/56





23/56




EXPERIMENT NO: 05

CHARACTERISTICS OF BJT CB CONFIGURATION

AIM: To study and plot the transistor characteristics in CB configuration.

APPARATUS REQUIRED: Transistor, BC107 -1 No.Regulated power supply (0-30V) -2 No. Voltmeter (0-30V) & (0-2V) -2 No.Ammeter (0-10mA) -1 No.Ammeter (0-1A) -1 No.Resistor, 10K -1 No. Resistor, 1K -1 No.Bread boardConnecting wires

THEORY:In this configuration the base is made common to both the input and out. The emitter is given the

input and the output is taken across the collector. The current gain of this configuration is less than unity.

The voltage gain of CB configuration is high. Due to the high voltage gain, the power gain is also high. In CB

configuration, Base is common to both input and output. In CB configuration the input characteristics relate

IE and V EB for a constant V CB. Initially let V CB = 0 then the input junction is equivalent to a forward biased

diode and the characteristics resembles that of a diode. Where V CB = +VI (volts) due to early effect I E

increases and so the characteristics shifts to the left. The output characteristics relate I C and V CB for aconstant I E. Initially I C increases and then it levels for a value I C = I E. When I E is increased I C also increases

proportionality. Though increase in V CB causes an increase in , since is a fraction, it is negligible and so I C

remains a constant for all values of V CB once it levels off.

PROCEDURE:INPUT CHARACTERISTICS:

It is the curve between emitter current I E and emitter-base voltage V BE at constant collector-base

voltage V CB.

1. Connect the circuit as per the circuit diagram.2. Set VCE=5V, vary VBE in steps of 0.1V and note down the corresponding IB.3. Repeat the above procedure for 10V, 15V.4. Plot the graph VBE Vs IB for a constant VCE.5. Find the h parameters.


24/56




OUTPUT CHARACTERISTICS: It is the curve between collector current I C and collector-base voltage V CB at constant emitter current I E.

1. Connect the circuit as per the circuit diagram.

2. Set IB=20A, vary VCE in steps of 1V and note down the corresponding IC .3. Repeat the above procedure for 40A, 80A, etc. 4. Plot the graph VCE Vs IC for a constant IB.5. Find the h parameters.

CIRCUIT DIAGRAM:

TABULAR COLUMN:

INPUT CHARACTERISTICS:


25/56





MODEL GRAPH:




26/56




RESULT:The transistor characteristics of a Common Base (CB) configuration were plotted and studied.

PRECAUTIONS: 1. The supply voltage should not exceed the rating of the transistor.2. Meters should be connected properly according to their polarities.

CONCLUSION:


27/56





28/56





29/56




EXPERIMENT NO: 06

CHARACTERISTICS OF BJT CC CONFIGURATION

AIM : To study and plot the transistor characteristics in CC configuration.

APPARATUS REQUIRED: Transistor, BC107 -1 No.Regulated power supply (0-30V) -2 No. Voltmeter (0-30V) & (0-5V) -2 No.Ammeter (0-30mA) -1 No.Ammeter (0-250A) -1 No.Resistor, 1K -2 No.Bread board

Connecting wires

THEORY:A BJT is a three terminal two junction semiconductor device in which the conduction is due to

both the charge carrier. Hence it is a bipolar device and it amplifier the sine waveform as they are

transferred from input to output. BJT is classified into two types NPN or PNP. A NPN transistor consists of

two N types in between which a layer of P is sandwiched. The transistor consists of three terminal emitter,

collector and base. The emitter layer is the source of the charge carriers and it is heartily doped with a

moderate cross sectional area. The collector collects the charge carries and hence moderate doping and

large cross sectional area. The base region acts a path for the movement of the charge carriers. In order to

reduce the recombination of holes and electrons the base region is lightly doped and is of hollow cross

sectional area. Normally the transistor operates with the EB junction forward biased.

In transistor, the current is same in both junctions, which indicates that there is a transfer of

resistance between the two junctions. One to this fact the transistor is known as transfer resistance of

transistor.

PROCEDURE:

INPUT CHARECTERISTICS:

1. Connect the circuit as per the circuit diagram.2. Set VCE, vary V BE in regular interval of steps and note down the corresponding I B reading.

Repeat the above procedure for different values of V CE.3. Plot the graph: V BC Vs IB for a constant V CE.


30/56




OUTPUT CHARECTERISTICS:

1. Connect the circuit as per the circuit diagram.2. Set I B, Vary V CE in regular interval of steps and note down the corresponding I C reading.

Repeat the above procedure for different values of I B.

3. Plot the graph: V CE Vs IC for a constant I B.

CIRCUIT DIAGRAM:

MODEL GRAPH:

INPUT CHARACTERISTICS: OUTPUT CHARACTERISTICS:


31/56




TABULAR COLUMN:


OUTPUT CHARACTERISTICS :


32/56




RESULT : The transistor characteristics of a Common Collector (CC) configuration were plotted.


CONCLUSION:


33/56





34/56





35/56




EXPERIMENT NO: 07

CHARACTERISTICS OF FIELD EFFECT TRANSISTOR

AIM: To plot the characteristics of FET and determine r d, gm, , IDSS, VP.

APPARATUS REQUIRED:

THEORY:FET is a voltage operated device. It has got 3 terminals. They are Source, Drain & Gate. When the

gate is biased negative with respect to the source, the PN junctions are reverse biased & depletion regionsare formed. The channel is more lightly doped than the p type gate, so the depletion regions penetratedeeply in to the channel. The result is that the channel is narrowed, its resistance is increased, & I D isreduced. When the negative bias voltage is further increased, the depletion regions meet at the center & I D is cutoff completely.

PROCEDURE:

DRAIN CHARACTERISTICS: 1. Connect the circuit as per the circuit diagram.2. Set the gate voltage V GS = 0V.3. Vary V DS in steps of 1 V & note down the corresponding I D. 4. Repeat the same procedure for V GS = -1V.5. Plot the graph V DS Vs ID for constant V GS.

TRANSFER CHARACTERISTICS:

1. Connect the circuit as per the circuit diagram.2. Set the drain voltage V DS = 5 V.3. Vary the gate voltage V GS in steps of 1V & note down the corresponding I D. 4. Repeat the same procedure for V DS = 10V.5. Plot the graph V GS Vs ID for constant V DS.

FET, BFW10 -1 No.Regulated power supply (0-30V) -2 No. Voltmeter (0-30V) & (0-10V) -2 No.Ammeter (0-30mA) -1 No.Resistor, 1K and 68K -2 No.Bread boardConnecting wires


36/56




CIRCUIT DIAGRAM:

MODEL GRAPH:

DRAIN CHARACTERISTICS:



37/56




TABULAR COLUMN: DRAIN CHARACTERISTICS:



38/56




FET PARAMETER CALCULATION:

Drain Resistance r d =V

DS V I D GS

Transconductance gm =I D

V V

GS DS

Amplification factor =rd.gm

RESULT: Thus the Drain & Transfer characteristics of given FET is Plotted.

Rd =

Gm = =

IDSS =Pinch off voltage V P =


CONCLUSION:


39/56





40/56





41/56




EXPERIMENT NO: 08

CLIPPER CIRCUTS WAVEFORMS

AIM: To observe waveforms at the input and output of clipper circuits .

THEORY: Clipping circuit is used to select for transmission that part of an arbitrary waveform which lies

above or below some reference level. Clipping circuit clips some portion of the waveform. Clippingcircuit is also referred to as voltage limiters. Clamping circuit preserves shape of the waveform whileclipping circuit does not preserve shape of waveform. Clipping circuit uses some reference level.Waveform above or below this reference level is clipped. Clipping circuits are also known as voltagelimiter or amplitude limiter or slicers. Some clipper circuits are explained here.

Positive cycle clipper circuits:

Positive cycle clipper circuits are shown in the figure with series and shunt diode. Transfercharacteristics and output waveform for sinusoidal input is shown.

For series diode:

When v i (t)0, Diode D is in OFF condition, input waveform is not available at the output andoutput remains zero.


42/56




For shunt diode:

When v i(t)0, Diode D is in OFF condition and acts like a OFF switch, input waveform is available at

the output.For negative cycle clipper , polarity of diode is reverse.

Series diode positive clipping with positive reference:

In the circuit shown in the following figure, DC reference voltage is used. This is useful of wedo not want to clip entire positive cycle but some portion of positive half cycle.

When v i(t) V R, Diode D is in OFF condition, input waveform is not available at the output and outputremains zero. Thus portion of output cycle clips as shown in the waveform.

Series diode positive clipping with negative reference:

If want to clip entire positive half cycle along with some portion of the negative cycle thennegative DC reference can be used as shown in the following figure. In this case only someportion of negative cycle passes to the output.

When v i(t) -V R, Diode D is in OFF condition, input waveform is not available at the output andoutput remains constant equal to V R. Thus entire positive cycle and some portion of negative cyclebelow VR clips.

Series diode negative clipping with reference:

Negative clipping can be achieved by changing polarity of the diode. Negative clipper withnegative reference voltage is shown in the following figure. This will clip some portion of negative cycle.


43/56




When v i(t)>-V R, Diode D is in ON condition, input waveform is available at the output.When v i(t)< -V R, Diode D is in OFF condition, input waveform is not available at the output andoutput voltage remains constant which is equal to VR.

Shunt diode positive clipping with negative reference voltage:

Shunt diode positive clipping with negative reference voltage is as shown in the followingcircuit. This will clip entire positive cycle and some portion of negative cycle as shown in thewaveform.

When v i(t) -V R, Diode D is in ON condition, input waveform is not available at the output andnegative voltage VR is extended to the output. Output voltage remains constant equal to V R. Thusentire positive cycle and some portion of negative cycle below VR clips.

Shunt diode negative clipping with negative reference:

Negative clipping with negative reference voltage can be achieved by reversing polarity of thediode. Some portion of negative cycle clips.

When v i(t)>-V R, Diode D is in OFF condition (open circuit) and input waveform is available at theoutput.When v i(t) < -V R, Diode D is in ON condition, input waveform is not available at the output andnegative voltage VR is extended to the output. Output voltage remains constant equal to V R. Thus entirepositive cycle and some portion of negative cycle below VR clips .


44/56




CIRCUIT DIAGRAM:

Draw circuit diagrams (as per circuit available in the laboratory or circuit connected onbreadboard):

PROCEDURE: 1. Connect function generator with CRO.

2. Set sine wave with 6V peak to peak. Ensure that offset voltage is 0.3. Connect the function generator at the input of the clipping circuit.4. Observe output waveforms on the CRO for different clipping circuits and draw output

waveforms.

OBSERVATION TABLE:


45/56




CONCLUSION:


46/56





47/56




EXPERIMENT NO: 09

CLAMPER CIRCUTS WAVEFORMS

AIM: To observe waveforms at the input and output of clamper circuits .

THEORY: Diodes are widely used in clipping and clamping circuits. Clamping circuits are used to change

DC level (average level) of the signal which adds or subtracts DC value with the signal. In clamping,shape of waveform remains same only offset value (DC level) will change. Positive clamping adds positiveDC level in the signal while negative clamping adds negative DC level in the signal. Capacitor is widelyused in the clamping circuit. Typical clamping waveform for the sinusoidal signal is shown below forpositive clamping and negative clamping.

Clamping circuit is used in video amplifier of television receiver to restore DC level of video signal topreserve overall brightness of the scene. Clamping circuit is also used in offset control of functiongenerator. Zero offset means no DC value is added in the AC signal.


48/56




Circuit operation:

Typical circuit operation of the positive clamping and negative clamping is given below.

Positive clamping:

Consider that 4V peak to peak signal with zero offset is applied at the input of the clamping circuit. Onthe first negative half cycle of the input signal, diode D turns ON because anode voltage is greaterthan cathode voltage. Capacitor charges to the negative peak voltage let us say -2V in ourexample. The value of R should be high so that it will not discharge the capacitance. After completionof negative cycle, positive cycle starts and diode turns OFF. Capacitance voltage is in series with theinput voltage. As per the Kirchhoffs law output voltage will be addition of input voltage andcapacitance voltage. Input signal is positive swing of +2V and capacitor voltage is +2V. Thus duringthe positive peak of the input voltage total output voltage will be +4V. We can consider that duringthe positive cycle capacitor acts like a battery and ads +2V in the input. Waveforms are drawn hereconsidering ideal diode, no leakage in the capacitance under ideal situations which will be different in

practical situations.

Negative clamping:

In a negative clamping circuit polarity of diode is reverse than in positive clamping. In our signalinput swings from -2V to +2V (peak to peak 4V). Diode turns ON during the positive cycle andcharge is stored in the capacitor. Capacitor will charge up to +2 V in our example. During thenegative cycle this voltage will be in series with the input voltage and gives total output -4V duringnegative peak of the input signal.


49/56


50/56




CONCLUSION:


51/56





52/56




EXPERIMENT NO: 09

RC PHASE SHIFT OSCILLATOR

AIM: 1. Identify the circuitry and schematic diagram of an RC phase shift oscillator.2. Describe the operating characteristics of the RC phase shift oscillator.3. Observe normal operations of the RC phase shift oscillator.

APPARATUS REQUIRED:

1. Dual Power supply2. Oscilloscope3. Operational amplifier4. Transistors

5.

Components as shown in figures6. Function generator.

THEORY:

The oscillator is an amplifier with positive feedback that generates a number of waveforms usuallyused in instrumentation and test equipments. An oscillator that generates a sinusoidal output is called aharmonic oscillator; the transistor is usually acts in the active region. The output of the relaxationoscillator is not sinusoidal depending on the transient rise and decay of voltage in RC or RL circuits. Thereare two types of RC oscillators:

Phase shift oscillators in which the output of an amplifier must be 180o out of phase with input. A generalcircuit diagram of a phase shift oscillator is shown in Fig.(l), where the amplifier is an ideal one. A phaseshift network (usually a resistor-capacitor network) is used to produce an additional phase shift of 180 atone particular frequency to develop the required positive feedback. From the mesh network equations ofthe feedback network, we find the feedback factor as,

The phase shift of the feedback network must be 180 then:

At this frequency = 1/29 and it is required that (A) must be at least 29 to satisfy oscillation condition asshown in Fig. (2). the phase shift oscillator is used to the range of frequencies for several hertz to severalkilohertz and so includes the range of audio frequencies. The frequency depends on the impedance


53/56




elements in the phase shift network. The phase shift oscillator circuit is not very suitable for generatingvariable frequency because the resistors and capacitors must be simultaneously changed to obtain therequired frequency control over a wide range therefore it is used mostly in fixed frequency applications.

CIRCUIT DIAGRAM:


54/56




PROCEDURE:1. Connect the circuit as shown in Fig (2), insert potentiometer of l k in the feedback arm.2. Measure the frequency of oscillation (f o) and the amplitude of the output voltage.3. Measure and draw the waveforms of points A, B and D.4. Observe the effect of variation of the potentiometer on the frequency of oscillation.5. Observe the effect of the variation of RE on f o.

CALCULATIONS:Output frequency of Oscillation =Amplitude of Output Voltage =

OBSERVATIONS: S.No A B C

(f o) (V o) (f o) (V o) (f o) (V o)

1

2

3

4

5

6


CONCLUSION:


55/56





56/56

Date post:	02-Jun-2018
Category:	Documents
Upload:	rohi89
View:	246 times
Download:	1 times

Lab Manual_Basic Electronics

Documents