Pdc Lab Manual 5g538

Pulse Circuits Lab

PART - II

PULSE CIRUITS LAB MANUAL

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Page 1

Pulse Circuits Lab

List of Experiments Part-II : PULSE CIRCUITS

1.

Linear Wave shaping Circuits

2.

Non Linear Wave shaping Circuits

3.

Comparison Operation of Comaparator

4.

Switching Characteristics of a Transistor

5.

Design a Bistable Multivibrator and draw its Waveforms

6.

Design a Astable Multivibrator and draw its Waveforms

7.

Design a Monostable Multivibrator and draw its Waveforms

8.

Response of Schmitt Trigger Circuit for a loop gain Less than and greater than one

9.

UJT relaxation Oscillator

10.

The output Voltage Waveform Of Boot strap Sweep Circuit

11.

The output Voltage Waveform Of Miller Sweep Circuit

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Pulse Circuits Lab Expt.No:01

LINEAR WAVE SHAPING AIM: To observe the effect of time constant on the output wave form of an RC low & high filter.

APPARATUS: S.NO

NAME OF THE EQUIPMENT

QUANTITY

1

Decade resistance box

1

2

capacitor (0.1uf)

1

3

Function generator

1

4

C.R.O

1

5

Bread Board

1

CIRUIT DIAGRAM:

A. Low RC Circuit

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Page 3

Pulse Circuits Lab B. High RC Circuit

THEORY:

LOW RC CIRCUIT: When a square is applied to a low filter RC circuit t=0 output voltage at that instant is 0 as output is taken across capacitor, and a capacitor can’t change its voltage instantaneously. Now capacitor starts raising its voltage exponentially with time constant RC and hence the output voltage reaches the maximum value. There is a fall in the input voltage by an amount of “V” abruptly. Again capacitor can’t change. Its voltage instantaneously. Therefore the output voltage Vo starts falling exponentially with time constant RC and continues. So on as long as square wave applied at the input.

HIGH CIRCUIT: When a square wave is applied for a high RC circuit at t = 0, since voltage across the capacitor can’t change instantaneously the out put voltage across the resistor raises to input voltage ‘V’. As capacitor voltage increases exponentially out put voltage starts falling exponentially. When the output voltage reaches the maximum value, there is an abrupt fall in input voltage by an amount ‘V’. This cause a fall in output voltage by ‘V’ from previous level. Thus the response curve comes to a negative voltage again the output voltage starts falling exponentially. When it reaches to a maximum level, then raise in input causes raise in output and same thing repeats again.

PROCEDURE 1. Connections are made as per circuit diagram

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Pulse Circuits Lab 2. Square wave input signal is applied to the integrator circuit and wave forms are noted with peak-peak amplitude and frequency is measured in each case RC< >t. 3. Respective graphs are drawn for RC>>t, RC=t, RC<
For RC<
Vo =

c=0.1 u f R=1KΩ

T=

For RC=t t=1 m sec

Vo =

c=0.1 u f R=10kΩ

T=

For RC>>t T=1 m sec

Vo =

C=0.1 u f R=100Kω

T=

PRECAUTIONS:

1. Connections should be firm. 2. Readings are noted without parallax error. 3. Before switch on the power supply all the knobs of power supply set at zero position.

RESULT:

The effect of time constant on the output wave form of Rc circuits is observed in all cases i.e., RC< >t.

ATRI

Page 5

Pulse Circuits Lab Expt.No:02

NON LINEAR WAVE SHAPING CLIPPERS AIM: To the response of different clipper circuits and draw the transmission characteristics of each clipping circuit.

APPARATUS:

S.NO.

EQUIPMENT

QUANTITY

1.

Diodes IN4007

2

2.

Resistors 1KΩ

1

3.

Function generator

1

4.

RPS

1

5.

CRO

1

SHUNT DIODE POSITIVE CLIPPER: In put R1 1.0k

V1

D1

t

1N4007GP 4V 1kHz 0Deg

Out put V2 1V

VR+Vr t

SHUNT DIODE NEGITIVE CLIPPER:

R2 output 1.0k

V3 4V 1kHz 0Deg

D2 1N4007GP

Out put VR-Vr V4 1V

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t

Page 6

Pulse Circuits Lab SERIES DIODE POSITIVE CLIPPER:

In put

D3 1N4007GP

t

R3 1.0k

V5

Out put

4V 1kHz 0Deg

V6

VR-Vr

1V

t

SERIES DIODE NEGATIVE CLIPPER:

D1 output V1

1N4007GP

R1 1.0k

4V 1kHz 0Deg

Out put V2

VR+Vr

1.5 V

t

CLIPPING AT TWO INDIPENDENT LEVELS:

output R2 1.0k

D2

D3

1N4007GP

1N4007GP

VR+Vr

V5 4V 1kHz 0Deg

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Out put V3

V4

1.5 V

1V

-(VR+Vr)

t

Page 7

Pulse Circuits Lab

THEORY: Clipping circuit basically limit the amplitude of the input signal applied to the either bellow or above a percent voltage level. They may also restrict the output wave forms to lie with in certain set voltage limits. Hence they are also called limiters or slicers. Their chief applications are to transmit that part of an arbitrary wave form, which lie above or below reference level.

PROCEDURE: 1. Make the connections as per the circuit diagram. 2. Observe the amplitude of the output wave for series and shunt diode clipping circuits using C.R.O and note down the wave forms. 3. Draw the corresponding output waveform graph.

For two level diode clipper: 1. VR1 and VR2 are selected such that VR2 ≠ VR1. 2. It is observed that the given sine wave is converted into an approximated rectangular waveform. 3. Corresponding graphs are drawn for the output waveform of two independent level clippers. RESULT:

The response of different clipping circuits is observed.

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Pulse Circuits Lab

CLAMPERS AIM: To the response of different clamping circuits.

APPARATUS: S.NO

NAME OF THE EQUIPMENT

QUANTITY

1.

Diodes (IN4007)

1

2.

Capacitor (0.01) µf

1

3.

Regulated power supply

1

4.

C.R.O

1

5.

Function Generator

1

6.

Bread Board

1

In put CIRCUIT DIAGRAM: Positive Clamper C1 V1

0.1uF

4V 1kHz 0Deg

D1

1N4007GP Out put

Negative Clamper C2 0.1uF

V2 4V 1kHz 0Deg

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D2 1N4007GP

Out put

Page 9

Pulse Circuits Lab THEORY: Clamping circuit add a d c level to an a c signal, Basically they pull up the maximum level of the input signal to a present reference level Vr and then allow the output to follow the input. Thus the output is always maintained below reference voltage level V r. The basic principle of the circuit is illustrated in above figure. In the first quarter of the input cycle the capacitor charges up to the maximum amplitude Vm and the diode is forward bias. Assuming that its forward resistance Rf is zero. The output remains zero voltage during this first quarter and the capacitor quickly charges to Vm. In the second quarter the input signal voltage falls from Vm. The diode is now reverse biased. Its reverse resistance Rr can be assumed infinite. The capacitor having no discharge path remains charged at Vm. The plate of the capacitor connected to the output terminals is negative. Also if the source has a resistance as zero ohms. It suffers no voltage drop. Hence the output Vo Vm –Vm. The entire swing if the output is form 0V to -2Vm corresponding to Vin = +Vm to Vin = -Vm respectively. The clamping level goes down to – Vr i.e. the + Ve peaks of the input signal get clamping at –Vr volts.

PROCEDURE: 1. Connections are made as per the circuit diagram. 2. For observing clamping waveform the AC/DC push button switch was to be kept in D.C. mode. 3. Note the values of the amplitude for each circuit from the C.R.O. 4. The output waveform was to be drawn on the graph for each circuit.

PRECAUTIONS: 1. Connections should be firm. 2. Readings are noted without parallax error. 3. Before switch on the power supply all the knobs of power supply are to be set at zero position.

RESULT: The response of different clamping circuits is observed. ATRI

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Pulse Circuits Lab Expt.No:03

COMPARISON OPERATION OF COMAPARATOR

AIM: To study the operation Comparison Operation of Comaparator.

APPARATUS:

SNO

1. 2.

NAME OF THE EQUIPMENT

Bread board trainer C.R.O

QUANTITY

1 1

3.

Function Generator

1

6.

Resistors

1

7.

RPS

1

CIRCUIT DIAGRAM:

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Pulse Circuits Lab PROCEDURE: 1. Connections are made as per the circuit diagram. 2. For observing clamping waveform the AC/DC push button switch was to be kept in D.C. mode. 3. Note the values of the amplitude for each circuit from the C.R.O. The output waveform was to be drawn on the graph for each circuit PRECAUTIONS: 1. Connections should be firm. 2. Readings are noted without parallax error. 3. Before switch on the power supply all the knobs of power supply are to be set at zero position.

RESULT: The response of different Comparison Operation of Comaparator is observed.

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Pulse Circuits Lab Expt.No:04

TRANSISTOR AS A SWITCH AIM: To study the operation of transistor as a switch.

APPARATUS:

SNO

1. 2. 3. 4.

NAME OF THE EQUIPMENT

Bread board trainer

QUANTITY

1

C.R.O

1

Transistor (SL 100)

1

LED

1

5.

Function Generator

1

6.

Resistors 4.7k

1

7.

100k

1

CIRCUIT DIAGRAM:

V in VCC 9V

R2 4.7k

t Q1 R1 100k

V1

BC107BP

Output

V Out 100% 90%

2V 1kHz 0Deg

10%

tr td

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ts

t

tf td

Page 13

Pulse Circuits Lab THEORY: When transistor makes a transition from its cut off state, to the saturation state or ON state it takes a finite time to do so. It takes the finite time for the reserve transition from the ON to OFF state.

DELAY TIME:

This time is taken during turn ON. It is the time duration form the point when the input pulse at base of the transistor reaches 10 % of its maximum amplitude, to the point when the collector current charges from 0 to 10% of its maximum amplitude.

RISE TIME:

This time is also taken during turn ON; it is the time interval in which the collector current pulse changes from 10% to 90% of its maximum valve.

STORAGE TIME:

The time interval during turn off transition of the transistor is between the points when the input pulse at the base changes to 10%of its maximum amplitude, to the point when the collector current changes from 100% to 90% of collector current.

FALL TIME: The time interval at turn off during which the collector current decreases from 90% to 10% of its maximum amplitude is the fall time.

PROCEDURE:

1. All the connections are made as per circuit diagram. 2. Observe the out put wave form that appears on C.R.O. with peak-to-peak amplitude and frequency and note these values.

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Pulse Circuits Lab 3. The delay time, rise time, storage time, fall time are calculated from their used definitions using the output waveform on C.R.O. 4. Switching action of transistor was observed by putting a led at output by reducing the frequency of input waveform. 5. The graph is plotted for the output waveform and the ON times OFF time are indicated. OBSERVATIONS:

td =

tr =

ts =

tf =

td =

PRECAUTIONS:

1. Connections should be firm. 2. Readings are noted without parallax error. 3. Before switch on the power supply all the knobs of power supply set at zero position. RESULT: 1. The switching action of transistor is observed efficiency. 2. Rise time, fall time, storage time, delay time are calculated. 3. The ON time and OFF time are noted.

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Pulse Circuits Lab Expt.No:05

BISTABLE MULTIVIBRATOR AIM: To study and the output wave form of a Bistable Multivibrator.

APPARATUS:

S.NO

NAME

OF

THE

QUANTITY

EQUIPMENT 1

Transistor ( SL 100 / BC107)

2

2

Resistors

2

2.2KΩ 15 KΩ

2

100 KΩ

2

3

Capacitors 0.047µ F

2

4

CRO

1

5

Bread board

1

CIRCUIT DIAGRAM: Vb1 Vbe set

VCC 12V

R5

C2

C1

2.2k

t

R1 2.2k

0.047uF

0.047uF

R2

R4

15k

15k

Q2

Vb2 Vbe set t

Q1

BC107BP

R6 100k

BC107BP

Vc1

R3 100k

Vbb -1.5v

Vce set Vc2

t

Vce set t

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Page 16

Pulse Circuits Lab THEORY: The circuit has two stable states, and switches or vibrates between these two states on the application of external trigger, Hence it is turned as Bistable Multivibrator. These are two biasing voltages One for the collector circuit and another for the base circuit. The fixed bias to the collector is provided by VCC and RC. The fixed bias to base is provided by VBB and R1 and R2. OPERATION: Consider that the transistor Q1 is OFF and the transistor is ON, the collector voltage of the OFF transistor is given by VCC – VCE (Sat). In the OFF mode only a small amount of leakage current flow through the transistor. For ON transistor we have VCC = 0. With the application of appropriate triggering pulse the stable state of binary can be changed. PROCEDURE: 1. Take a bread board and connect the components as per circuit diagram. 2. Apply the supply voltage VCC = + 12 V and connect CRO at the base of Q1. 3. Note down the wave forms time period and amplitude of wave form at the base of Q1. 4. Repeat the same procedure to note down the wave forms at base of Q2. 5. Similarly note down the wave forms at VC1 & VC2 of Q1 & Q2 respectively. 6. Note down the VBE (Sat) and (VCE (Sat) voltages. 7. Draw the wave forms on a graph. PRACAUTIONS: 1. Connections should be firm. 2. Readings are noted without parallax error. 3. Before switch on the power supply all the knobs of power supply set at zero position. 4. Increase the power supply slowly. 5. After note down the readings switch off the power supply.

RESULT: Responses at the base and collector points of the Bistable Multivibrator are observed. ATRI

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Pulse Circuits Lab Expt.No:06

ASTABLE MULTIVIBRATOR AIM: To understand the response at base and collector points of the Astable Multivibrator

APPRATUS: S.NO

NAME OF THE EQUIPMENT

1

Transistor (BC 107)

2

Resistors

QUANTITY

2

2.2kΩ

2

15kΩ

2

3

Capacitor 0.04 µf

2

4

Regulated power supply

1

5

CRO

1

6

1

Bread board

CIRCUIT DIAGRAM: VC1 Vcc

VCC 12V

R4 2.2k

C1

R2

R3

15k

15k

R1 2.2k

C2

Vce sat VC2

0.047uF

t

0.047uF

Q2

Q1

BC107BP

BC107BP

Vce sat t VB2 Vbe sat t

VB1 Vbe sat

t

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Pulse Circuits Lab THEORY: An Astable Multivibrator has no stable states. The two transistors switch alternately between two quasi stable states. No external trigger is required to effect this change and hence is called as free running Multivibrator. RC1& RC2 are the collector resistors for transistors Q1&Q2 respectively. C1&C2 are coupling capacitors. Resistor R1&R2 provide ON state base current to the transistor T1&T2 during saturation region.

OPERATION: At time t=0, when the power supply voltage gets applied, due to slight mismatch Ic1 flowing through Q1 is little more then the collector Ic2 of Q2. Thus rate of fall of Vc1 is more then that of Vc2. so Vc1< Vcc will make the base of Q2 negative. This make the collector voltage Vc2 increase towards Vcc. This increase in Vc2 will be transferred through capacitor C2 to the base of Q1 and increasing the condition in Q1. Thus when Astable Multivibrator is switched we have the following conditions. 

Q1 is in saturation



Q2 is in off region

PROCEDURE:

1. Take a bread board and connect the components as per circuit diagram. 2. Apply the supply voltage vcc =+12v and connect the C.R.O at desired points to observe the wave forms. 3. Note down the wave forms time period, amplitude from C.R.O by connecting it at vc1, vc2, & vb2 respectively. 4. Calculate the frequency of wave forms. 5. Check whether theoretical and practical values are correct or not.

THEORETICAL VALUES:

R1 =15K=R2 C1=C2=0.047uf ATRI

Page 19

Pulse Circuits Lab TI=0.69 R1C1 T2=0.69R2C2 TOTAL TIME PERIOD =T=1.38 RC 0.97ms=1ms Frequency =1/T=1/1ms=1kHz PRACTICAL VALUES :

1. Time period at Q1=T1= 2. Time period at Q2=T2= 3. Total Time period T=T1+T2= 4. Frequency=1/T

RESULT:

The response at base and collector point of Astable Multivibrator is observed.

ATRI

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Pulse Circuits Lab Expt.No: 07

MONOSTABLE MULTIVIBRATOR AIM: To construct the transistor monostable Multivibrator and observe the response at base and collector points.

APPARATUS: S.NO

NAME OF TE EQUIPMENT

QUANTITY

1

Transistor (SL 100 or BC 107)

2

2

Resistors 1KΏ

2

10KΏ

2

100KΏ

1

3

Capacitors 0.047μF

2

4

Regulated power supply

1

5

CRO

1

6

Bread board

1

CIRCUIT DIAGRAM VCC 12V

R1

R5

1.0k

10k

Vc2

R4 C2

1.0k

0.047uF

C1

R3

Vceset

10k

0.047uF

t

Q1

Q2

BC107BP

BC107BP

Vb1 Vbe sat

R2

Vr t

100k

Vbb(-1.5v) t

ATRI

Page 21

Pulse Circuits Lab THEORY: The basic collector coupled monostable circuit is shown in figure. STABLE STATE: Normally Q2 is in the ON state. Because it gets a sufficient base current through R3.This causes Q1 to be in the OFF state as Q2 collector which fed to the base of Q1 is at its low Vcc saturation value. This is fact that a negative bias applied at the base of Q1 turns it OFF. This is to the stable state.

ENTRY TO QUASI STABLE STATE: Now if Q2 is forced to become off due to large external trigger applied at its base, its collector voltage rises sharply. This gives a positive voltage through the voltage divider network of R1 and R2 at the base of Q1. This is sufficient to over come. The effect of its negative bias and exceed the cut in voltage of it’s BE terminal it turn ON. The circuit has now extended a quasi stable state.

RETURN TO STABLE STATE: When Q1 turns ON, the capacitors find a convenient path to change up to VCC through R3 and Q1. If the capacitor is charging till the voltage at the base of Q2 exceeds its cut in voltage at this point Q2 turn ON again and Q2 turn OFF. The circuit returns to its stable state. During the quasi stable state the voltage at the collector of Q2 has a high VCC level. Thus a pulse is obtained. The width of the pulse is given by T = 0.69 R3 C.

PROCEDURE: 8. Take a bread board and connect the components as per circuit diagram. 9. Apply the supply voltage VCC = + 12 V and connect CRO at the base of Q1. 10. Note down the wave forms time period and amplitude of wave form at the base of Q1. 11. Repeat the same procedure to note down the wave forms at base of Q2. 12. Similarly note down the wave forms at VC1 & VC2 of Q1 & Q2 respectively. 13. Calculate the Quasi stable time period. ATRI

Page 22

Pulse Circuits Lab 14. Draw the wave forms on a graph RECORD OF OBSERVATION: THEORITICAL VALUES: R2 = 10 KΩ C2 = 0.047µ F tp = 0.69 R2 C2 PRACTICAL VALUES: δ= VBE (sat) =

Vγ = tp=

PRECAUTIONS: 1. Connections should be firm. 2. Readings are noted without parallax error. 3. Before switch on the power supply all the knobs of power supply set at zero position. 4. Increase the power supply slowly. 5. After note down the readings switch off the power supply RESULT: The responses at base and collector point of monostable Multivibrator are observed.

ATRI

Page 23

Pulse Circuits Lab Expt.No:08

SCHMITT TRIGGER AIM: To generate a square wave form by using Schmitt trigger circuit.

APPARATUS:

S.NO

NAME OF THE EQUIPMENT

1

QUANTITY

transistor (SL100)

2

2

820Ω

resistors

1

1.2k Ω

1

1k Ω

1

10k

2

150 Ω 3

1

capacitors 0.047µf

4

1

function generator

5

1

C.R.O

1

6

regulated power supply

1

7

bread board

1

CIRCUIT DIAGRAM VCC 4.5V

R1 C1

1.0k

Vin R6 1.0k

UTP LTP

0.047uF

R2 1.2k

Q1

t

Q2

R5 820 BC107BP

R3 10k

V out BC107BP

Vcc

V1 4V 1kHz 0Deg

R4 150

IeRe t

ATRI

Page 24

Pulse Circuits Lab THEORY: Schmitt trigger is a special type of Bistable Multivibrator. It differs from the basic binary circuit. In the basic circuit there won’t be any resistive coupling between the output of Q2 and the input of Q1. Although the collector of Q1and the base of Q2 are coupled in usual manner. The emitter of Q1 and Q2 are ed, and they are grounded through a common resistor Rc. The base of Q1is connected to a voltage source Vi. It should be noted that the output of a Schmitt trigger is a square wave what ever the wave form of the input signal.

PROCEDURE 1. Connections are made as for the circuit diagram. 2. Apply the supply voltage VCC = 4.5 V & connect the C.R.O at output terminals. 3. Apply the input square wave frequency 1KHZ and amplitude of 4V(P-P). 4. Observe the output wave form on C.R.O & note down the amplitude & time period

of

square wave form. 5. Sketch the waveform on graph sheet.

RECORD OF OBSERVATIONS: 1. The time period of square waveform 2. The amplitude of square waveform

PRECAUTIONS: 1. Connections should be tight. 2. Before switch on the power supply set the all knobs at zero positions. 3. Increase the power supply slowly and smoothly.

RESULT: Square wave is generated by using Schmitt trigger circuit.

ATRI

Page 25

Pulse Circuits Lab Expt.No:09

UJT RELAXATION OSCILLATOR AIM: To construct and study the operation of Uni junction transistor as a relaxation oscillator.

APPARTUS:

S.NO

NAME OF THE EQUIPMENT

QUANTITY

1.

Bread board trainer

1

2.

UJT 2N2646

1

3.

Resistors 330Ω

1

47Ω

1

4.

Decade resistance box

1

5.

Capacitor 0.1µf

1

CIRCUIT DIAGRAM:

10K _LIN Key = A

R3

Vb1

R2 330

Vb2

50%

t output Vp

2N2646

V out C1 0.1uF

ATRI

Vv

R1 47

Vb1 t

Page 26

Pulse Circuits Lab THEORY: The injunction transistor has only the P-N junction. it has a P-type emitter alloyed to lightly doped N type material. There are two bases, B1 and B2. Base B1 being closer to the emitter that base B2. The P-N junction is formed between the P-type emitter and N-type silicon bar. RB1 is the resistance between base B1 and the emitter, and it is a basically a variable resistance its value being dependent upon the emitter Ie. RB2 is the resistance between B2 and the emitter and its value is fixed. Vp =Vr +Vγ Vp = Vr + VBB

Vγ = VBB

It is Obvious that if VE < VP that UJT is OFF, If VE > VP the UJT is ON

VV =Valley Voltage,

VP = peak voltage.

It is seen that when the capacitor voltage VS rises to the value VP the UJT readily conducts. When the UJT becomes ON the capacitor discharges and its voltage falls. When the voltage falls to the valley point Vv. The UJT becomes OFF and the capacitor charges again to Vp. This cycle of charging and discharging of the capacitor C repeats and as a result a saw tooth waveform of voltage across C is generated.

The output across C shows in figure.

Ts = Sweep time Tr = Return time Tv= Valley time

PROCEDURE:

(1) Take bread broad and connect the component as per circuit diagram. (2) Connect VBB=15 and connect C.R.O across capacitor “C”.

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Page 27

Pulse Circuits Lab (3) Note down the waveform and connect C R O across RB1and RB2 and note down the wave forms (4) Calculate the time period and check whether it is equal to the theoretical value or not. (5) Sketch the wave forms on graph

RECORD OF OBSERVATIONS:

THEORITICAL VALUE: T = RC (log 1/ 1- ŋ)

PRACTICAL VALUE: T=

PRECAUTIONS:

1. Connections should be tight. 2. Readings are noted without parallel error. 3. Before switch on the power supply all the knobs of power supply should set at zero position. RESULT:

Response of the UJT Relaxation Oscillator is observed.

ATRI

Page 28

Pulse Circuits Lab Expt.No:10

BOOTSTRAP SWEEP CIRCUIT AIM: To study the working of bootstrap sweep circuit.

APPRATUS:

S.NO

NAME OF THE EQUIPMENT

QUANTITY

1

Transistor (SL100)

1

2

Resisters 1kΩ

1

1MΩ

1

3

Capacitors 100µf

1

1µf

1

4

Function generator

1

5

CRO

1

6

Regulated power supply

1

7

Bread board

1

CIRCUIT DIAGRAM:

+ Vcc 12 v V input

R1 1.0k

t

Q1

C1 100uF

4 V (P-P) 1Khz

Vs

BC107BP

V out

R2

C2

1.0M

1uF

t

ATRI

Page 29

Pulse Circuits Lab THEORY: The circuit is transistor base sweep circuit. The output sweep circuit is ramp voltage generally the sweep circuits are employed to trigger the horizontal amplifier of C R T’s in C R O’s sweep circuit is used in television sweep voltage trigger the horizontal amplifier.

A ramp voltage is obtained by allowing a constant current to flow through it. This is achieved by using the transistor as switch. When a transistor is ON it makes to flow a constant current through the output capacitor.

A capacitor and resister at the base of the transistor forms a differentiator circuit that produces spikes at the base of the transistor. The negative spikes make the transistor is off. These results in charging the output capacitor to Vcc through Rc1. thus the output voltage taken across the capacitor raises exponentially. When the positive excursion occurs at the base, the transistor will be ON. Thus the capacitor discharging through the transistor. Thus this cycle continues hence giving up a sweep wave form.

The output waveform is 180 ° out off phase of the input excitation signal since the transistor is in CE mode

PROCEDURE: 1. Connect the components as per circuit diagram. 2. Connect the Vcc = +12 v, and apply square wave of frequency 1 kHz and 4v (p-p) amplitude at the input terminals. 3. Take the output in CRO across the 1µf capacitor. 4. Observe the waveform on CRO 5. Note down the p-p amplitude and time period of the output sweep wave form. 6. Draw the input and output wave forms in graph RECORD OF OBSERVATION: Amplitude of sweep waveform: Time period of sweep waveform:

RESULT: The working of Bootstrap sweep circuit is studied. ATRI

Page 30

Pulse Circuits Lab Expt.No:11

MILLER SWEEP CIRCUIT

AIM: To study the working of Miller sweep circuit.

APPRATUS:

S.NO

NAME OF THE EQUIPMENT

1

Transistor (BC107)

2

Resisters

3

Capacitors

4

Function generator

5

CRO

6

Regulated power supply

7

Bread board

CIRCUIT DIAGRAM:

ATRI

Page 31

Pulse Circuits Lab

THEORY: The circuit is transistor base sweep circuit. The output sweep circuit is ramp voltage generally the sweep circuits are employed to trigger the horizontal amplifier of C R T’s in C R O’s sweep circuit is used in television sweep voltage trigger the horizontal amplifier.

A ramp voltage is obtained by allowing a constant current to flow through it. This is achieved by using the transistor as switch. When a transistor is ON it makes to flow a constant current through the output capacitor.

A capacitor and resister at the base of the transistor forms a differentiator circuit that produces spikes at the base of the transistor. The negative spikes make the transistor is off. These results in charging the output capacitor to Vcc through Rc1. thus the output voltage taken across the capacitor raises exponentially. When the positive excursion occurs at the base, the transistor will be ON. Thus the capacitor discharging through the transistor. Thus this cycle continues hence giving up a sweep wave form.

PROCEDURE:

ATRI

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Pulse Circuits Lab

1. Test all the components and set up the circuit. 2. Switch ON the VCC supply. Q1 is in ON state and Q2 is in OFF state by measuring the collector voltages. RECORD OF OBSERVATION: Amplitude of sweep waveform: Time period of sweep waveform:

RESULT: The working of Miller sweep circuit is studied. ATRI

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