basic electronics (code: 131101)

Basic Electronics (Code: 131101)

B.E. SEM. III (COMPUTER), Year 2012-13 (Odd Sem.)

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Enrollment No:

GUJARAT POWER ENGINEERING AND RESEARCH

INSTITUTE, MEHSANA (APPROVED BY AICTE)

(Affiliated to Gujarat Technological University)

CERTIFICATE

This is to certify that Mr./Ms.________________________________

Enrollment No. ___________________ of semester _____________________has

satisfactorily completed the laboratory work in the course

_____________________________________ within the four walls of the Institute.

Date of submission:

Faculty In-charge Head of Department

GUJARAT POWER ENGINEERING AND RESEARCH INSTITUTE, MEHSANA

Affiliated with Gujarat Technological University (GTU)

B.E. SEM. III (ELECTRICAL), Year: 2012-13 (Odd Sem.)

131101: Basic Electronics

INDEX

Sr.

No. TITLE Page

From To

DATE SIGN REMARK

1 To obtain the characteristics of P-N junction

diode.

2 To obtain the characteristics of LED.

3 To obtain the characteristics of Zener diode.

4 To verify the operation of half wave, full

wave centre tapped & bridge rectifier.

5 To calculate the ripple factor & efficiency

of half wave, full wave centre tapped & full

wave bridge rectifier.

6 To perform shunt & series positive and

negative clipper circuits.

7 To perform positive and negative clamper

circuits.

8 To perform biased shunt & series positive &

negative clamper

9 To obtain the input & output characteristics

of C.E. configuration of BJT.

10 To obtain the input & output characteristics

of C.B. configuration of BJT

EXPERIMENT NO.1 DATE: _______

AIM:-To obtain the forward biased & Reverse biased characteristics of P-N

junction diode.

SPECIFICATION:-

On board DC power supply : +12V DC

Mains supply : 230V AC ±10%, 50Hz

Ammeter Range : 0 mA to 200 mA

Voltmeter Range : 0V to 12V

APPARATUS:-

(1)NV6501 Diode Characteristics Trainer

(2) Patch Cords

THEORY:- A diode is an electrical device allowing current to move through it in one

direction with greater ease than in the other. The most common type of diode in

modern circuit design is the semiconductor diode, although other diode

technologies exist. Semiconductor diodes are symbolized in schematic diagrams

as shown below:

Figure 1 When placed in a simple battery-lamp circuit, the diode will either allow or

prevent current through the lamp, depending on the polarity of the applied voltage

Figure 2 When the polarity of the battery is such that electrons are allowed to flow through

the diode, the diode is said to be forward-biased. Conversely, when the battery is

"backward" and the diode blocks current, the diode is said to be reverse biased. A

diode may be thought of as a kind of switch: "closed" when forward-biased and

"open" when reverse-biased.

V-I Characteristic :-

The static voltage-current characteristic for a P-N Junction Diode is shown in

Figure 3.

Figure 3

Forward Characteristic :-

When the diode is in forward-biased and the applied voltage is increased from

zero, hardly any current flows through the device in the beginning. It is so

because the external voltage is being opposed by the internal barrier voltage VB

whose value is 0.7 V for Si and 0.3 V for Ge. As soon as VB is neutralized,

current through the diode increases rapidly with increasing applied supply

voltage. It is found that as little a voltage as 1.0 V produces a forward current of

about 50mA.

Reverse Characteristic:-

When the diode is reverse-biased, majority carrier are blocked and only a small

current (due to minority carrier) flows through the diode. As the reverse voltage is

increased from zero, the reverse current very quickly reaches its maximum or

saturation value Io which is also known as leakage current. It is of the order of

nanoamperes (nA) and microamperes (µA) for Ge. As seen from Figure 3, when

reverse voltage exceeds a certain value called breakdown voltage VBR, the leakage

current suddenly and sharply increases, the curve indicating zero resistance at this

point.

PROCEDURE:-

To plot Forward Characteristics proceed as follows :-

1. Before switch ‘On’ the supply connect TP1 and TP2 to Voltage positive and

negative terminals respectively.

2. Switch ‘on’ the power supply.

3. Check +12V DC power supply.

4. Now switch ‘Off’ the supply.

5. Rotate potentiometer P1 fully in CCW (counter clockwise direction).

6. Connect Current positive terminal to test point TP4 and Current negative

terminal to test point TP10, to measure diode current ID (mA).

7. Connect Voltage positive terminal to test point TP3 and Voltage negative

terminal to TP11, to measure diode voltage VD.

8. Switch ‘On’ the power supply.

9. Vary the potentiometer P1 so as to increase the value of diode voltage VD from

0 to 1V (0.83V) in step and measure the corresponding values of diode current

ID in an observation Table 1.

10. Plot a curve between diode voltage VD & diode current ID as shown in figure 3

(First quadrant) using suitable scale, with the help of observation Table 1.

This curve is the required forward characteristics of Si diode.

11. Switch ‘off’ the supply.

To plot Reverse Characteristics of a Si diode proceed as follows:-

1. Disconnect previous connections.


3. Connect Current positive terminal to test point TP5 and Current negative

terminal to test point TP10 to measure diode current ID (mA).

4. Connect Voltage positive terminal to test point TP3 and Voltage negative

terminal to TP11 to measure diode voltage VD.


6. Vary the potentiometer P1 so as to increase the value of diode voltage VD from

zero to 10V in step and measure the corresponding values of diode current ID

in an observation Table 2.

7. Plot a curve between diode voltage VD & diode current ID as shown in figure 3

(third quadrant) using suitable scale with the help of observation Table 2. This

curve is the required reverse characteristics of Si diode.


OBSERVATION TABLE:-

Table:1 Forward biased Characteristics Table:2 Reverse biased Characteristics

Sr.

No.

Diode Voltage

(VD)

Diode current

ID ( µA )

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

Sr.

No.

Diode Voltage

(VD)

Diode current

ID (mA)

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

GRAPH:- Plot the graph of Diode Voltage and Diode current ID for both Forward biased and

Reverse biased.

CONCLUSION:- Comment on the nature of graph.

QUIZ:-

1. What is the difference between the semiconductor, conductor and

insulator?

2. What is the difference between the intrinsic and extrinsic

semiconductors?

3. Explain what the barrier potential is and how it is created.

4. Compare the depletion regions in forward bias and reverse bias.

5. What happens to the barrier potential when the temperature

increases?


AIM:-To obtain the forward biased & Reverse biased characteristics ofLED.

SPECIFICATION:-

On board DC power supply:+12V DC

Mains supply:230V AC ±10%, 50Hz

AmmeterRange:0 - 200 mA

VoltmeterRange:0 - 12V

APPARATUS:-


(2) Patch Cords

THEORY:- Diodes, like all semiconductor devices, are governed by the principles described

inquantum physics. One of these principles is the emission of specific-frequency

radiantenergy whenever electrons fall from a higher energy level to a lower

energy level.

A diode intentionally designed to glow like a lamp is called a light-emitting diode,

orLED. Diodes made from a combination of the elements gallium, arsenic,

andphosphorus (called gallium-arsenide-phosphide) glow bright red, and are some

of themost common LEDs manufactured. By altering the chemical constituency

of the PNjunction, different colours may be obtained. Some of the currently

available coloursother than red are green, blue, and infra-red (invisible light at a

frequency lower thanred). Other colours may be obtained by combining two or

more primary-colours (red,green, and blue). The schematic symbol for an LED is

a regular diode shape inside ofa circle, with two small arrows pointing away

(indicating emitted light).

Figure 1

This notation of having two small arrows pointing away from the device is

commonto the schematic symbols of all light-emitting semiconductor devices.

Conversely, if adevice is light-activated (meaning that incoming light stimulates

it), then the symbolwill have two small arrows pointing toward it. It is interesting

to note, though, thatLEDs are capable of acting as light-sensing devices: they will

generate a smallvoltage when exposed to light, much like a solar cell on a small

scale. This propertycan be gainfully applied in a variety of light-sensing

circuits.Because LEDs are made of different chemical substances than normal

rectifyingdiodes, their forward voltage drops will be different. Typically, LEDs

have muchlarger forward voltage drops than rectifying diodes, anywhere from

about 1.6 volts toover 3 volts, depending on the color. Typical operating current

for a standard sizedLED is around 20 mA. When operating an LED from a DC

voltage source greater than the LEDs forward voltage, a series-connected

"dropping" resistor must beincluded to prevent full source voltage from damaging

the LED. LED starts emittinglight as its forward voltage reaches at a particular

level and its intensity will increasefurther with the increase in applied forward

voltage. LEDs emit no light when reversebiased. In fact, operating LEDs in

reverse direction will quickly destroy them if theapplied voltage is quite large.

LEDs V-I characteristic curve is shown in Figure 2.

Figure 2 Characteristics of LED

PROCEDURE:-

To plot Forward Characteristics proceed as follows:-


2. Connect Current positive terminal to test point TP6 and Current

negativeterminal to test point TP10 to measure diode current ID (mA).

3. Connect Voltage positive terminal to test point TP3 and Voltage

negativeterminal to TP11 to measure LED voltage VD.


5. Vary the potentiometer P1 so as to increase the value of LED voltage VD

fromzero to maximum in steps and measure the corresponding values of LED

currentID in an observation Table 1.

6. Also consider the effect on light intensity of LED, with the change in

diodevoltage and diode current.


To plot Reverse Characteristics of a Si diode proceed as follows:-


2. Connect Current positive terminal to test point TP7 and Current

negativeterminal to test point TP10 to measure LED current ID (mA).

3. Connect Voltage positive terminal to test point TP3 and negative terminal

toTP11 to measure LED voltage VD.


5. Vary the potentiometer P1 so as to increase the value of diode voltage VD

fromzero to maximum in steps and measure the corresponding values of

diodecurrent ID in an Observation Table 2.


OBSERVATION TABLE:-

Table:1Forward biased Characteristics Table:2Reverse biased Characteristics

GRAPH:- Plot the graph of Diode Voltage and Diode current ID for both forwardbiased

andReverse biased.

CONCLUSION:-

Comment on the nature of graph.

Sr.

No.

Diode Voltage

(VD)

Diode current

ID (mA)

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

Sr.

No.

Diode Voltage

(VD)

Diode current

ID ( µA )

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

QUIZ:-

1) In what bias condition is an LED normally operated?

2) What is the operating principle of LED?

3) What happens to the light emission of an LED as the forward current increases?

4) Name two types of LED in terms of their light-emission spectrum.

5) The forward voltage drop of an LED is 0.7 V (true or false)

EXPERIMENT NO. 3 DATE: _______

AIM:-To obtain the characteristics of Zener diode.

SPECIFICATION:-

On board DC power supply: +12V DC

Mains supply: 230V AC ±10%, 50Hz

Ammeter Range: 0 mA to 200 mA

Voltmeter Range: 0V to 12V

APPARATUS:-


(2) Patch Cords

THEORY:- It is the reverse-biased heavily-dopped silicon (or germanium) P-N Junction diode

which is operated in the breakdown region where current is limited by both

external resistance and power dissipation of the diode. Silicon is preferred to

diode because of its higher temperature and current capability. Zener breakdown

occurs due to breaking of covalent bonds by the strong electric field set up in the

depletion region by the reverse voltage. It produces an extremely large number of

electrons and holes, which constitute the reverse saturation current (called zener

current Iz) whose value is limited only by the external resistance in the circuit.

V-I Characteristic:-

Figure 1 shows typical characteristics in the negative quadrant. The forward

characteristic is simply that of an ordinary forward-biased junction diode. The

important points of the reverse characteristic are Vz = Zener breakdown voltage.

Iz min = Minimum current to sustain breakdown, Iz max = Maximum Zener

current limited by, maximum power dissipation. Since its reverse characteristic is

not exactly vertical, the diode possesses some resistance called Zener dynamic

impedance. Its value is given by Zz =

Vz /

Iz. Zener diode are available having

zener voltage of 2.4V to 200V. This voltage is temperature dependent. The

product Vz, Iz, gives their power dissipation. Maximum ratings vary from 150mV

to 50W.

Figure:-1

For proper working of a Zener diode in any circuit, it is essential that it must

1. Be reverse-biased,

2. Have voltage across it which is greater than Vz,

3. Be in a circuit where current is less than Iz maximum

PROCEDURE:-

To plot Forward Characteristics proceed as follows :- 1. Rotate potentiometer P1 fully in CCW (counter clockwise direction).

2. Connect Current positive terminal to test point TP8 and Current negative terminal

to test point TP10 to measure diode current ID (mA).

3. Connect Voltage positive terminal to test point TP3 and negative terminal to TP11

to measure diode voltage VD.


5. Vary the potentiometer P1 so as to increase the value of Zener voltage Vz from zero

to 0.8 in step and measure the corresponding values of Zener current Iz in an

observation Table 1.

6. Plot a curve between diode voltage Vz and diode current Iz as shown in figure 1

(First quadrant) using suitable scale, with the help of Observation Table 1. This

curve is the required Forward Characteristics of Zener diode.

7. Switch ‘Off’ the supply.

To plot Reverse Characteristics of a Si diode proceed as follows:- 1. Rotate potentiometer P1 fully in CCW (counter clockwise direction).

2. Connect Current positive terminal to test point TP9 and Current negative terminal

to test point TP10 to measure diode current ID (mA).

3. Connect Voltage positive terminal to test point TP3 and Voltage negative terminal

to TP11 to measure voltage VD diode.


5. Vary the potentiometer P1 so as to increase the value of diode voltage VD from zero

to 6.8V in steps and measure the corresponding values of diode current Iz in an

observation Table 2.

6. Plot a curve between diode voltage Vz and diode current Iz as shown in figure 1

(third quadrant) using suitable scale, with the help of Observation Table 2. This

curve is the required Reverse Characteristics of Zener diode.

7. Switch ‘Off’ the supply.

OBSERVATION TABLE:-

Table:1 Forward biased Characteristics Table:2 Reverse biased Characteristics

GRAPH:- Plot the graph of Diode Voltage and Diode current ID for both forward biased and

Reverse biased.

CONCLUSION:- Comment on the nature of graph.

QUIZ:- 1. What is the difference between the zener diode and p-n junction

diode?

2. List the application of zener diode.

3. Compare zener and avalanche breakdown.

Sr.

No.

Diode Voltage

(Vz)

Diode current

Iz ( mA )

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

Sr.

No.

Diode Voltage

(Vz)

Diode current

Iz (mA)

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

EXPERIMENT NO. 4 DATE: _______

AIM: - To verify the operation of half wave, full wave centre tapped & bridge

rectifier.

SPECIFICATION:-

Mains Supply: 230V ±10%, 50Hz

Transformer Rating: 9 V center tapped (300mA)

Half-wave Rectifier Output: 4V DC

Center-Tapped Rectifier Output: 8V DC

Bridge Rectifier Output: - 8V DC

Load: Resistive 220 ohms, ½ Watt

APPARATUS:-

(1) NV6503 Rectifier Trainer

(2) Patch Cords

(3) CRO

(4) Digital Multimeter (DMM)

THEORY:- Rectifier: - A rectifier is a circuit, which uses one or more diodes to convert AC

Voltage into pulsating DC voltage. It may be broadly categorized in

(a) Half-wave Rectifier

(b) Full-wave Rectifier : Full-wave Rectifier is again subdivided into

i. Center-tapped Rectifier

ii. Bridge Rectifier

Half-wave Rectifier:-

Figure 1 shows the half-wave rectifier circuit. It consists of a single diode in a

series with a load resistor. The input to the half-wave rectifier is an AC waveform

as shown in Figure 1. The working of a half-wave rectifier circuit may be studied

by considering separately the positive and negative half cycles of the AC input

voltage.

Figure 1

During the positive half-cycle of the AC input voltage, the diode is forward biased

and conducts for all instantaneous voltages greater than the threshold voltage (0.7

V for silicon and 0.3 V for germanium diodes). However, for all practical

purposes, we assume that the diode is forward biased, whenever the AC input

voltage goes above zero. While conducting, the diode acts as a short- circuit, so

that the circuit current flows and produces a voltage across the load resistor (RL).

The voltage produced across the load resistor has the same shape as that of the

positive input half cycle of AC input voltage as shown in Figure 1. The waveform

of diode current (which is equal to load current) is also shown in Figure 1.

During negative half-cycle, the diode is reverse biased and hence it does not

conduct. Thus, there is no current flow or voltage drop across load resistor (RL)

i.e. ID = 0 and VO=0. The net result is that only the positive half cycle of the AC

input voltage appears across RL. It means that only the positive half cycle of the

AC input voltage is utilized for delivering AC power.

Full - wave Rectifier: A full-wave rectifier is a circuit, which allows a

unidirectional current to flow through the load during the entire input cycle as

shown in Figure 2. The result of full-wave rectification is a DC output voltage

that pulsates every half-cycle of the input. On the other hand, a half-wave rectifier

allows the current to flow through the load during positive half-cycle only.

Figure 2 Full wave Rectifier, with input and output voltage waveforms

Center-tapped Full-wave Rectifier:

Figure 3 Center-tapped Full-wave Rectifier

During the positive input half-cycle, forward biases the diode D1 and reverse-

biases the diode D2.

As a result of this, the diode D1 conducts some current whereas the diode D2 is

‘Off’.

During the negative input half-cycle, this reverse-biases the diode D1 and forward-

biases the diode D2. As a result of this, the diode D1 is ‘Off’ and the diode D2

conducts some current.

Full-wave Bridge Rectifier:

It uses four diodes connected across the main supply, as shown in Figure 4. The

operation of the circuit may be studied as follows :

Figure 4 Bridge rectifier with step-down transformer

When the input voltage is positive as shown in Figure 4, the diodes D1 and D2 are

forward biased and conduct some current in the direction as indicated in the

figure. A voltage is developed across the resistance RL due to the current flow

through it. The voltage looks like the positive half of the input cycle. At this time

the diodes D3 and D4 are reverse biased. When the input voltage is negative as

shown in Figure 4, the diodes D3 and D4 are forward biased and conduct some

current in the same direction through RL as during the positive half- cycle. During

this time, the diodes D1 and D2 are reverse biased. As a result of this action, a full-

wave rectified output voltage is developed across the resistance RL.

PROCEDURE:-

Procedure for Half Wave Rectifier:- 1. Make the connections on the Rectifier Trainer NV6503.

a. Connect output of transformer (0-9 Vrms) to the input of half-wave rectifier

i.e. connect TP1 and TP2 across TP4 and TP5 using 2mm patch cords.

b. Directly connect the output of rectifier to load i.e. connect TP6 and TP7

across TP19 and TP20.

c. For using filter, connect output of half-wave rectifier to the input of filter i.e.

connect TP6 to TP15 and TP7 to TP16.

d. Now connect the output of filter to the load i.e.connect TP17 and TP18

across TP19 and TP20.

2. Connect the mains cord to the Rectifier Trainer and switch on the mains

supply.

3. Now switch ‘On’ the power switch of the trainer.

4. Connect CRO across TP1 and TP2 and observe the step down output of

transformer.

5. Connect CRO across TP19 and TP20 and observe the output which is a

rectified voltage waveform or pulsating DC.

6. Measure output frequency on CRO and you will observe that in half-wave

rectifier, the output frequency is same as that of input. fout = fin (50 Hz)

Procedure for Center - Tapped Rectifier:- 1. Make the connections on the Rectifier Trainer NV6503.

a. Connect output of transformer (9-0-9 Vrms) to the input of center-tapped full-

wave rectifier i.e. connect TP1 and TP3 across TP8 and TP9 using 2mm patch

cords.

b. Directly connect output of center-tapped rectifier, TP10 and center-tap of

transformer TP2 across load i.e. TP19 and TP20.

c. For using filter, connect output of center-tapped rectifier to the input of filter

i.e. connect TP10 to TP15 and TP2 to TP16.

d. Now connect the output of filter to the load i.e. connect TP17 and TP18 across

TP19 and TP20.

2. Connect the mains cord to the Rectifier Trainer and switch on the mains

supply.




5. Measure output frequency on CRO and you will observe that in center-tapped

rectifier, the output frequency is double as that of input. fout = 2fin (100 Hz

approximately)

Procedure for Bridge Rectifier:- 1. Make the connections on the Rectifier Trainer NV6503 .

a. Connect output of transformer (0-9 Vrms) to the input of bridge rectifier i.e.

connect TP1 and TP2 across TP11 and TP14 using 2mm patch cords.

b. Connect the output of rectifier to the load i.e. connect TP13 and TP12 across

TP19 and TP20.

c. For using filter, connect output of bridge rectifier to the input of filter i.e.,

connect TP13 to TP15 and TP12 to TP16.

d. Now connect the output of filter to the load i.e. connect TP17 and TP18 across

TP19 and TP20.

2. Connect the mains cord to the Rectifier Trainer and switch ‘On’ the mains

supply.




5. Measure output frequency on CRO and you will observe that in bridge

rectifier, the output frequency is double as that of input. fout = 2fin (100 Hz

approximately)

CALCULATION:- Calculate the value of output d.c. voltage Vdc and output direct current Idc

WAVEFORM:-

Plot the waveform of Output Voltage and current.

CONCLUSION:-

Comment on the nature of waveform.

QUIZ:- (1) For half wave rectifier, there is current through the load for

approximately what percentage of the input cycle?

(2) What is the average of a half wave rectified voltage with a peak

value of 10V ?

(3) How does a full wave voltage differ from a half wave voltage?

(4) Which type of full wave rectifier has the greater output voltage for

the same input voltage and transformer turns ratio?

(5) What is the average value of a full wave rectified voltage with a

peak value of 60 V ?


AIM:- To calculate the Ripple Factor and Efficiency of various Rectifiers.

SPECIFICATION:-

On board DC power supply : +12V DC

Mains supply: 230V AC ±10%, 50Hz

Ammeter Range: 0 mA to 200 mA

Voltmeter Range: 0V to 12V

APPARATUS:-


(2) Patch Cords

(3)CRO

(4) Digital Multimeter (DMM)

THEORY:-

Ripple Factor: The AC component present in the output is called a ripple. As a

matter of fact, the ripple is undesirable and accounts for pulsations in the rectifier

output. Mathematically, the ripple factor,

Ripple Factor of a Half-wave Rectifier:

We know that the average value of load current in a half- wave rectifier,

…………..(1)

Where Im is the maximum value of load current

The r.m.s. value of the load current for a half-wave rectifier is given by,

………….(2)

Substituting these values of Idc and Irms in the expression for ripple factor,

If ripple factor is expressed in terms of a percentage, its value is 121%. This

indicates that the amount of AC component present in the output of a half-wave

rectifier is 121% of DC output voltage. Hence the half-wave rectifier is not very

successful in converting the current from AC to DC.

Ripple Factor of a Full-wave Rectifier :

We know that the average value of load current in a full-wave rectifier (either

centertapped

or bridge rectifier) is given by the relation,

The r.m.s. value of the load current for a full-wave rectifier is given by,

Substituting these values of Idc and Irms in the expression for ripple factor,

From the above result it is evident that the ripple factor of a full-wave rectifier is

0.482 and is much smaller than that of a half-wave rectifier. Because of this

reason, full-wave rectifier is used more commonly in actual practice.

Efficiency : It may be defined as the ratio of DC power delivered to the load to

the AC input

power from the secondary winding of the transformer. Mathematically, the

rectifier efficiency,

Efficiency of a Half-wave Rectifier:

We know that the efficiency of a rectifier is given by the expression,

We also know that for a half-wave rectifier,

Substituting the values of Idc and Irms in equation (i),

Now efficiency will be maximum, if RL >> Rf = 0.406 or 40.6 %.

It shows that efficiency of a half-wave rectifier is 40.6% under the condition that

the value of load resistance is very large as compared to the forward resistance of

a diode (i.e., RL >> Rf) However, in actual practice, the efficiency is always less

then 40.6 %.

Efficiency of a Full-wave Rectifier:

As we know that rectifier efficiency is given by the relation,

We also know that for a full-wave rectifier,

Substituting the values of Idc and Irms in equation (i),

Now efficiency will be maximum if RL >> Rf. Thus, max = 0.812 or 81.2 %.

It shows that maximum efficiency of a full-wave rectifier is twice that of half-

wave rectifier. It means that a full-wave rectifier is twice as effective as a half-

wave rectifier.

OBSERVATION:-

Type Vr.m.s Vm

Half Wave Rectifier

Centre tapped Wave Rectifier

Bridge Rectifier

CALCULATION:-

Type Ripple Factor efficiency

Half Wave Rectifier

Centre tapped Wave Rectifier

Bridge Rectifier

CONCLUSION:-

QUIZE:- 1).Define the ripple factor.

2). Define the effiency of rectifier.

3). Explain the term : PIV in rectifier service.

4). Compare the half wave and full wave rectifier.

5). Comments on the full wave rectifier output.


AIM: To Perform shunt & series positive and negative Clipper Circuits.

APPARATUS: -

NV6511 Trainer Kit CRO Multimeter

THEORY:-

Wave Shaping Circuits

A process by which non-sinusoidal as well as sinusoidal waveforms are altered in

passing through the circuit elements (such as diodes, resistors, inductors and

capacitors) is called wave shaping. The wave shaping is used to perform any one

of the following functions:

1. To generate one wave from the other.

2. To limit the voltage level of the waveform to some preset value and

suppressing all other voltage levels in excess of the preset level.

3. To cut-off the positive and negative portions of the input waveform.

4. To hold the waveform to a particular DC level.

The wave shaping is important in most of the signal process systems and is

performed by the circuits known as differentiators, integrators, limiters, clippers

and clampers.

Types of Wave Shaping Circuits:

Following two types of wave shaping circuits are important from the subject point

of view:

1. Linear wave shaping circuits:

The circuits, which make use of only linear circuit elements such as the inductors,

capacitors and resistors, are known as linear wave shaping circuits.

2. Nonlinear wave shaping circuits:

The circuits, which (in addition to linear circuit elements) make use of nonlinear

circuit elements such as diodes and transistors are known as nonlinear wave

shaping circuits. Such circuits are used to perform functions of amplitude

limiting, clipping and clamping.

Clipping Circuits:

A wave shaping circuit which controls the shape of out waveform by removing or

clipping a portion of the applied wave is known as clipping circuit. The clippers

are used in Radar, Digital and other electronic devices. The various types of

clippers are:

Positive Clipper:

The clipper which removes the positive half cycles of the input voltage is known

as positive clipper.

Negative Clipper:

The clipper which removes the negative half cycles of the input voltage is known

as negative clipper.

Biased Clipper:

A biased clipper is used when it is desired to remove a small portion of positive or

negative half cycle of the signal voltage.

Combination Clipper: The combination of a biased positive clipper and a biased negative clipper is

called combination clipper. Such a clipper circuit can clip at two-independent

levels depending upon the bias voltages.

PROCEDURE:-

Procedure for Series Positive Clipper:

Connect point 1 and point 2 of Sine Wave Generator Section to point 7 and

point 8 of Series Positive Clipper respectively. Connect the mains cord to the trainer and switch on the mains supply. Switch ON the power switch of the trainer. Connect CRO across TP3 and TP4 and observe the output, which is a

positively clipped waveform. Draw the input and output waveforms on the graph paper.

Procedure for Series Negative Clipper:


point 12 of Series Negative Clipper respectively.. Connect the mains cord to the trainer and switch on the mains supply. Switch ON the power switch of the trainer. Connect CRO across TP7 and TP8 and observe the output, which is a

negatively clipped waveform. Draw the input and output waveforms on the graph paper.

Procedure for Shunt Positive Clipper:


point 10 of Shunt Positive Clipper respectively.. Connect the mains cord to the trainer and switch on the mains supply. Switch ON the power switch of the trainer. Connect CRO across TP5 and TP6 and observe the output, which is a

positively clipped waveform. Draw the input and output waveforms on the graph paper

Procedure for Shunt Negative Clipper:


point 14 of Shunt Negative Clipper respectively. Connect the mains cord to the trainer and switch on the mains supply. Switch ON the power switch of the trainer. Connect CRO across TP9 and TP10 and observe the output, which is a

negatively clipped waveform. Draw the input and output waveforms on the graph paper

CONCLUSION:-

Comment on the nature of output waveform.

QUIZ:-

1. Define ripple factor.

2. What are the disadvantages of a half wave rectifier circuit?

3. Define the peak inverse voltage.

4. What is the advantage of bridge rectifier?

5. Why filter circuit is necessary with rectifier?


AIM:-To Perform positive and negative Clamper Circuits.

APPARATUS: -


THEORY:-













and clampers.



of view:









Clamping Circuits:

The circuits, with which the waveform can be shifted in such a way so that a

particular part of it (say positive or negative peak) is maintained at a specified voltage

level, is called a clamping circuit (or simply a clamper). As a matter of fact, a

clamping circuit introduces (or restores) a dc level to an ac signal. Thus a clamping

circuit is also known as dc restorer. Such circuits are used in television receivers to

restore the original dc reference signal to the video signal.

Positive Clamper:

When a clamper shifts the original signal in vertical upward direction, it is known

as positive clamper.

Negative Clamper:

When a clamper shifts the original signal in vertical downward direction, it is

known as positive clamper.

Biased Clampers:

A biased clamper means that the clamping can be done at any voltage level other than

zero.

PROCEDURE:-

Procedure for Positive Clamper:


point 38 of Positive Clamper respectively.. Connect the mains cord to the trainer and switch on the mains supply. Switch ON the power switch of the trainer. Connect CRO across TP21 and TP22 and observe the output, which is lifted up

so as the trough of the waveform touch the reference level (or horizontal axis).

This causes the waveform to clamp positively at 0V and is known as positively

clamped waveform at 0V.. Draw the input and output waveforms on the graph paper.

Procedure for Negative Clamper:


Point 40 of Negative Clamper respectively.. Connect the mains cord to the trainer and switch on the mains supply. Switch ON the power switch of the trainer. Connect CRO across TP 23 and TP 24 and observe the output waveform

which is shifted down so as the crest of the waveform touch the reference

level (or horizontal axis). This causes the waveform to clamp negatively at 0V

and is known as negatively clamped waveform at 0V. Draw the input and output waveforms on the graph paper.

CONCLUSION:-


QUIZ:-

1. What is transfer characteristics? State its physical significance.

2. What is rectifier ?

3. Which are the important characteristics of a rectifier circuit ?

4. Why diode can be used as a rectifier ?

5. Define transformer utilization factor


AIM:- To perform biased positive & negative clamper.

APPARATUS: -


THEORY:-













and clampers.



of view:









Clamping Circuits:

The circuits, with which the waveform can be shifted in such a way so that a

particular part of it (say positive or negative peak) is maintained at a specified voltage

level, is called a clamping circuit (or simply a clamper). As a matter of fact, a

clamping circuit introduces (or restores) a dc level to an ac signal. Thus a clamping

circuit is also known as dc restorer. Such circuits are used in television receivers to

restore the original dc reference signal to the video signal.

Positive Clamper:

When a clamper shifts the original signal in vertical upward direction, it is known

as positive clamper.

Negative Clamper:

When a clamper shifts the original signal in vertical downward direction, it is

known as positive clamper.

Biased Clampers:

A biased clamper means that the clamping can be done at any voltage level other

than zero. Now consider a circuit shown in figure 1. Here a battery of 5V is added

in such a way that the clamping takes place positively at –5V as shown in figure 2

Figure 1 Biased clamper

Figure 2 Output waveforms

Similarly, it is also possible to clamp the input waveform positively at +5V by

reversing the battery connections.

PROCEDURE:-

Procedure for Biased Positive Clamper: Connect the Sine Wave Generation to the input terminals of the circuit. Connect the mains cord to the trainer and switch on the mains supply. Switch ON the power switch of the trainer. Connect the positive DC power supply to appropriate terminals for biased

clamping circuits. Connect the CRO across the output terminals and observe the output

waveform on the CRO. Draw the input and output waveforms on the graph paper

Procedure for Negative Clamper:

Connect the Sine Wave Generation to the input terminals of the circuit. Connect the mains cord to the trainer and switch on the mains supply. Switch ON the power switch of the trainer. Connect the negative DC power supply to appropriate terminals for biased

clamping circuits. Connect the CRO across the output terminals and observe the output

waveform on the CRO. Draw the input and output waveforms on the graph paper.

CONCLUSION:-


QUIZ:-

1. What is clipper circuit?

2. What is clamper circuit?

3. Explain the application of clipper circuit.

4. Explain the application of clamper circuit.

5. Explain the biased clamper circuit.

EXPERIMENT NO. 09 DATE: _____________

AIM: To Obtain the Input & Output Characteristics of CE Configuration of

BJT.

APPARATUS: -

NPN Transistor

Resistances 1KΩ

DC Power Supply 0 – 30 V

Ammeter 0 – 1 mA & 0 – 10 mA

Voltmeter 0 – 2 V & 0 – 30 V

Bread Board

THEORY:-

The CE configuration of transistor has two types of characteristics.

I/P characteristic

O/P characteristic

Input Characteristic:

It is the curve between base current IB & base-emitter voltage VBE at constant

collector-emitter voltage VCE. From this characteristic, we can have the following

information.

The input characteristic is same as that of the forward diode curve since the

base-emitter section of transistor is a diode & it is forward bias.

IB increases less rapidly with VBE, thus the input resistance of CE connection

is somewhat higher.

The characteristic gives the i/p resistance which is the ratio of change in base-

emitter voltage (∆VBE) to the resulting change in base current (∆IB) at constant

collector-emitter voltage VCE.

Input resistance, ri = (∆VBE) / (∆IB) at constant VCE

Output Characteristic: It is the curve between collector current IC & collector-emitter voltage VCE at

constant base current IB. From this characteristic, we can have the following

information.

The collector current IC varies with VCE only at very low voltages (<1V).The

transistor is never operated in this region. When the collector-emitter voltage

VCE is increased above 1-2 volt, the collector current becomes constant. It

means the collector current IC is independent of collector-emitter voltage VCE.

The value of VCE up to which collector current IC changes is called Knee

voltage (Vknee).The transistor operates above this region as above knee region,

IC is almost constant.

For any value of VCE above knee voltage, the collector current is

approximately equal to β X IB.

The o/p resistance is the ratio of change in collector-emitter voltage (∆VCE) to

the resulting change in collector current (∆IC) at constant base current.

Output resistance, ro= (∆VCE) / (∆IC) at constant IB

PROCEDURE:-


Connect the circuit as per the circuit diagram.

Set VCE=4V, very VBE in step of 0.1V & note down the corresponding IB.

Repeat the above procedure for VCE=6 & 8 V.

Plot the graph VBE vs IB for a constant VCE.

Output Characteristic:

Connect the circuit as per circuit diagram.

Set IB=20μA, very VCE in step of 1V & note down the corresponding IC.

Repeat the above procedure for IB=40μA.

Plot the graph VCE vs IC for a constant IB.

Plot the graph VCB vs. IC for a cons

OBSERVATIN TABLE:- Input Characteristics

Sr.

No.

VCE= ___ V VCE= ___ V VCE= ___ V

IB

(mA)

VBE

(Volt)

IB

(mA)

VBE

(Volt)

IB

(mA)

VBE

(Volt)

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

Output Characteristics

CONCLUSION:-

Sr.

No.

IB= ___ µA IB= ___ µA

IC

(mA)

VCE

(Volt)

IC

(mA)

VCE

(Volt)

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

EXPERIMENT NO. 10 DATE: _____________

AIM: To Obtain the Input & Output Characteristics of CB Configuration of

BJT.

APPARATUS: -

NPN Transistor

Resistances 1KΩ

DC Power Supply 0 – 30 V

Ammeter 0 – 1 mA & 0 – 10 mA

Voltmeter 0 – 2 V & 0 – 30 V

Bread Board

THEORY:-

The CB configuration of transistor has two types of characteristics:

I/P characteristic

O/P characteristic.


It is the curve between emitter current IE & emitter-base voltage VBE at constant

collector-base voltage VCB. From this characteristic, we can have the following

information.

The emitter current IE increases rapidly with small increase in emitter-base

voltage VBE. It means that input resistance is very small.

The emitter current is almost independent of collector-base voltage VCB.

The characteristic gives the i/p resistance which is the ratio of change in

emitter-base voltage (∆VBE) to the resulting change in emitter current (∆IE) at

constant collector-base voltage VCB.

Input resistance, ri = (∆VBE) / (∆IE) at constant VCB

Output Characteristic:

It is the curve between collector current IC & collector-base voltage VCB at

constant emitter current IE. From this characteristic, we can have the following

information.

The collector current IC varies with VCB only at very low voltages (< 1V).The

transistor is never operated in this region.

When the collector-base voltage VCB is increased above 1-2 volt, the collector

current becomes constant. It means the collector current IC is independent of

collector-base voltage VCB & depends upon IE only. Thus the entire emitter

current will go to the collector terminal.

The o/p resistance is very high because a very large change in collector-base

voltage produces only a small change in collector current. The o/p resistance

is the ratio of change in collector-base voltage (∆VCB) to the resulting change

in collector current (∆IC) at constant emitter current.

Output resistance, ro= (∆VCB) / (∆IC) at constant IE

PROCEDURE:-

Input Characteristic

Connect the circuit as per the circuit diagram.

Set VCB=4V, very VEB in step of 0.1V & note down the corresponding IE.

Repeat the above procedure for VCB=6 & 8 V.

Plot the graph VEB vs. IE for a constant VCB.

Output Characteristic

Connect the circuit as per circuit diagram.

Set IE=2mA, very VCB in step of 1V & note down the corresponding IC.

Repeat the above procedure for IE=4mA.

Plot the graph VCB vs. IC for a cons

OBSERVATIN TABLE:-

Input Characteristics

Sr.

No.

VCB=___V VCB=___V VCB=___V

IE

(mA)

VEB

(Volt)

IE

(mA)

VEB

(Volt)

IE

(mA)

VEB

(Volt)

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

Output Characteristics

CONCLUSION:-

Sr.

No.

IE=___mA IE=___mA

IC

(mA)

VCB (Volt) IC

(mA)

VCB (Volt)

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

basic electronics (code: 131101)

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