CSIL SIMULATION

SIMULATION EXPERIMENTS

    7. SIMULATION OF TUNED COLLECTOR OSCILLATOR

Ex. No:

Date   :

AIM:

            To design, and simulate the Tuned Collector oscillator using transistor with PSPICE

Multisim software.

APPARATUS REQUIRED:

S.NO	APPARATUS NAME	RANGE	QUANTITY
1.	PC With PSPICE MULTISIM SOFTWARE		1

CIRCUIT DIAGRAM

MODEL GRAPH

THEORY

A tuned collector oscillator circuit using a transformer is shown in Figure. The primary of the transformer forms a tuned circuit with capacitor C and it decides the frequency of oscillation. Its amplifier provides a phase difference of 180° and an additional phase difference of 180° is provided by the transformer, it will result in positive feedback. For the oscillatory action, the transistor amplifier provides sufficient gain. The resistors R1, R2 and RE provide D.C bias to the transistor. CE and C2 are bypass capacitors, so that resistors RE and R2 have no effect on A.C operation. The D.C bias is provided by the resistors R1 and R2 through the low-resistance secondary winding which also provides A.C feedback. To maintain oscillations, more positive feedback is required which is achieved by increasing coupling of the transformer. The frequency of oscillations produced by the tank circuit depends upon the value of primary inductance L and capacitance C

PROCEDURE:

1. Open the Multisim software with a new document.
2. Make the connections as per the circuit diagram
3. Obtain a sine wave output. Measure the frequency and amplitude of the sine wave output.
4. Copy the output and paste on a word/paint document.
5. Take Printout and paste on the record note book.

RESULT:

Thus the Tuned Collector oscillator was designed and simulated with help of PSPICE Multisim software.           

8. SIMULATION OF TWIN T OSCILLATOR USING TRANSISTORS

Ex. No:

Date   :

AIM:

            To design, and simulate the Twin T oscillator using transistor with PSPICE Multisim.

APPARATUS REQUIRED:

S.NO	APPARATUS NAME	RANGE	QUANTITY
1.	PC With PSPICE MULTISIM SOFTWARE		1

CIRCUIT DIAGRAM

MODEL GRAPH

THEORY

                  The Twin-T is a band-stop RC circuit (or notch filter). It blocks all but the resonant frequency  in the negative feedback loop. Oscillation cannot occur at frequencies above or below the resonant frequency. The basic twin "T" filter is a passive notch filter composed of two T-networks, with maximum attenuation occurring at  fnotch = 1/(2pRC)   One of these T networks has one resistor and two capacitors, while the other has two resistors and one capacitor. At the notch frequency fnotch of the twin-T filter, the total phase shift is zero, which satisfies the requirement for oscillation. This is why the circuit generates a sine wave with a frequency equal to fnotch = 1/(2pRC).

PROCEDURE:

1. Open the Multisim software with a new document.
2. Make the connections as per the circuit diagram
3. Obtain a sine wave output. Measure the frequency and amplitude of the sine wave output.
4. Copy the output and paste on a word/paint document.
5. Take Printout and paste on the record note book.

RESULT:

Thus the Twin T oscillator was designed and simulated with help of PSPICE Multisim software. 

Oscillator	Frequency of Oscillation
	Theoretical	Practical
Twin T

9. SIMULATION OF WEIN BRIDGE OSCILLATOR USING TRANSISTORS

Ex. No:

Date   :

AIM:

            To design, and simulate the Wein Bridge oscillator using transistor with PSPICE Multisim.

APPARATUS REQUIRED:

S.NO	APPARATUS NAME	RANGE	QUANTITY
1.	PC With PSPICE MULTISIM SOFTWARE		1

FORMULA:

1.  Wien Bridge oscillator:

(i) Frequency of Oscillation, fo = 1 / 2 п√R1R2C1C2

DESIGN:

1. Wien Bridge oscillator:

Frequency of Oscillation, fo = 1 / 2 п√R1R2C1C2

                        R₁ = R₂= 1K, C₁=C₂=0.1uF then f_o=1.59KHz.

CIRCUIT DIAGRAM:

MODEL GRAPH:

THEORY:

An RC oscillator basically consists of an amplifier and a feedback network made up of resistance and capacitances. The phase shift oscillator circuit can be realized by op-amp. The op-amp is used in non-inverting mode to provide 180· phase shift. The output of op-amp is fed to three section RC network which provides the needed 180· phase shift. The gain of op-amp can be adjusted with the help of the resistances R_f and R_i. The gain is so adjusted that the product of gain of op-amp (Av) and the feedback network gain (β) is slightly greater than one, to get the required oscillations.

In the Wien Bridge oscillator the feedback signal is connected to positive terminal so that the op-amp is working as a non-inverting amplifier. The Wein bridge circuit is connected between the amplifier input & output terminals. The bridge has series RC network in one arm & parallel RC network in the adjoining arm. In the remaining two arms, th  e resistors R₁ & R_f are connected. The phase angle criterion for oscillation is that the total phase shift around the circuit must be zero. This condition occurs only when the bridge is balanced.

PROCEDURE:

1. Open the Multisim software with a new document.
2. Make the connections as per the circuit diagram
3. Obtain a sine wave output. Measure the frequency and amplitude of the sine wave output.
4. Copy the output and paste on a word/paint document.
5. Take Printout and paste on the record note book.

TABULATION:

Oscillator	Amplitude (Volts)	Time period (ms)	Frequency of Oscillation
			Theoretical	Practical
Wien Bridge			1.59KHZ

VIVA QUESTIONS:

1. What is meant by sustained oscillation?
2. How do you classify the oscillators?
3. State the two conditions of oscillations.
4. What is feedback network?
5. How the zero phase shift is obtained in the Wien Bridge oscillator?
6. Which components are used for high frequency oscillators?
7. What are the advantages of RC oscillators?

RESULT:

Thus the Wien Bridge oscillator was designed and simulated with help of PSPICE Multisim software.    

Oscillator	Frequency of Oscillation
	Theoretical	Practical
Wien Bridge

10. SIMULATION OF DOUBLE TUNED AMPLIFIER

Ex. No:

Date   :

AIM:

            To design, and simulate the Double tuned amplifier using transistor with PSPICE Multisim.

APPARATUS REQUIRED:

S.NO	APPARATUS NAME	RANGE	QUANTITY
1.	PC With PSPICE MULTISIM SOFTWARE		1

CIRCUIT DIAGRAM

MODEL GRAPH

THEORY

Figure shows the circuit of a double tuned amplifier. It consists of a transistor amplifier containing two tuned circuits; one (L1C1) in the collector and the other (L2C2) in the output as shown. The high frequency signal to be amplified is applied to the input terminals of the amplifier. The resonant frequency of tuned circuitL1C1 is made equal to the signal frequency. Under such conditions, the tuned circuit offers very high impedance to the signal frequency. Consequently, large output appears across the tuned circuit L1C1.The output from this tuned circuit is transferred to the second tuned circuit L2C2 through mutual induction. Double tuned circuits are extensively used for coupling the various circuits of radio and television receivers. The frequency response of a double tuned circuit depends upon the degree of coupling i.e. upon the amount of mutual inductance between the two tuned circuits.

PROCEDURE

1. Open the Multisim software with a new document.
2. Make the connections as per the circuit diagram
3. Obtain a sine wave output. Measure the frequency and amplitude of the sine wave output.
4. Copy the output and paste on a word/paint document.
5. Take Printout and paste on the record note book.

RESULT:

Thus the Double Tuned Amplifier was designed and simulated with help of PSPICE Multisim software.

11. SIMULATION OF ASTABLE MULTIVIBRATOR USING TRANSISTORS

Ex. No:

Date   :

AIM:

            To design, and simulate the Astable Multivibrator using transistor with PSPICE Multisim.

APPARATUS REQUIRED:

S.NO	APPARATUS NAME	RANGE	QUANTITY
1.	PC With PSPICE MULTISIM SOFTWARE		1

CIRCUIT DIAGRAM   :

THEORY:

An electronic circuit that generates square waves (or other non-sinusoidal such as rectangular, saw tooth waves) is known as a multivibrator. A multivibrator is a switching circuit, which depends for operation on positive feedback. It is basically a two stage amplifier with output of one feedback to input of the other.

A multivibrator which generates square waves of its own (i.e. without any external triggering pulse) is known as an astable or free running multivibrator. This multivibrator has no stable state. It switches back and forth from one state to the other, remaining in each state for a time determined by circuit constants. The first transistor conducts and the other stays in the OFF state for some time. After this period of time, the second transistor is automatically turned ON and the first transistor is turned OFF. Thus the multivibrator will generate a square wave of its own. The width of the square wave and its frequency will depend upon the circuit constants.

                              

MODEL GRAPH

PROCEDURE:

1. Open the Multisim software with a new document.
2. Make the connections as per the circuit diagram
3. Obtain a sine wave output. Measure the frequency and amplitude of the sine wave output.
4. Copy the output and paste on a word/paint document.
5. Take Printout and paste on the record note book.

RESULT:

Thus the astable multivibrator was designed and simulated using PSPICE multisim software.       

7. MONOSTABLE MULTIVIBRATOR

Ex. No:

Date  :  

                 

AIM:

            To design, and simulate the mono stable multivibrator using transistor with PSPICE Multisim.

APPARATUS REQUIRED:

S.NO	APPARATUS NAME	RANGE	QUANTITY
1.	PC With PSPICE MULTISIM SOFTWARE		1

 CIRCUIT DIAGRAM   :

THEORY:

An electronic circuit that generates square waves (or other non-sinusoidal such as rectangular, saw tooth waves) is known as a multivibrator. A multivibrator is a switching circuit, which depends for operation on positive feedback. It is basically a two stage amplifier with output of one feedback to input of the other.A multivibrator in which one transistor is always conducting (i.e. in the ON state) and the other is non-conducting state (i.e. in the OFF state) is called a monostable multivibrator or one-shot multivibrator. A monostable multivibrator has only one stable state. If one transistor is conducting and the other one is non-conducting, the circuit will remain in this position .It is only with the application of external pulse that the circuit will interchange the states. However, after some time, the circuit will automatically switch back to the original stable state and remains there until another pulse is applied. Thus a monostable multivibrator cannot generate wave of its own. Only external pulse will cause it to generate the square wave.

                  

MODEL OUTPUT WAVEFORM:

RESULT:

    Thus the monostable multivibrator using multisim was simulated and verified.

8.IBISTABLE MULTIVIBRATOR

Ex. No:

Date  : 

                  

AIM:

            To design, and simulate the Bistable Multivibrator using transistor with PSPICE Multisim.

APPARATUS REQUIRED:

S.NO	APPARATUS NAME	RANGE	QUANTITY
1.	PC With PSPICE MULTISIM SOFTWARE		1

CIRCUIT DIAGRAM

DESIGN:

VCC =12V; VBB = -12V; IC = 2mA; VCE (sat) = 0.2V; VBE (sat) = 0.7V ,RC =  5.9 KΩ, R2 ≤ hfe RC = 315 * 5.9 * 103 = 1.85MΩ

R2 = 1.8MΩ, Let R1 = 10KΩ, C1 = C2 = 50pF

THEORY:

A Bistable circuit is one which can exist indefinitely in either of two stable states and which can be induced to make an abrupt transition from one state to the other by means of external excitation. The Bistable circuit is also called as Bistable multivibrator, Eccles jordon circuit, Trigger circuit, Scale-of-2 toggle circuit, Flip-Flop & Binary. A bistable multivibratior is used in a many digital operations such as counting and the storing of binary information. It is also used in the generation and processing of pulse-type waveform. They can be used to control digital circuits and as frequency dividers. There are two outputs available which are complements of one another. i.e. when one output is high the other is low and vice versa .

MODEL GRAPH:

RESULT:

    Thus the Bistable multivibrator using multisim was simulated and verified.

9. SCHMITT TRIGGER

Ex. No:

Date  :  

                

AIM:

            To design, and simulate the Schmitt trigger using transistor with PSPICE Multisim.

APPARATUS REQUIRED:

S.NO	APPARATUS NAME	RANGE	QUANTITY
1.	PC With PSPICE MULTISIM SOFTWARE		1

THEORY:

Schmitt trigger is a bistable circuit and the existence of only two stable states results form the fact that positive feedback is incorporated into the circuit and from the further fact that the loop gain of the circuit is greater than unity. There are several ways to adjust the loop gain. One way of adjusting the loop gain is by varying Rc1. Under quiescent conditions Q1 is OFF and Q2 is ON because it gets the required base drive from Vcc through Rc1 and R1. So the output voltage is Vo=Vcc-Ic2Rc2 is at its lower level. Untill then the output remains at its lower level. Schmitt trigger circuit is a emitter coupled bistable circuit, and existence of only two stable states results from the fact that positive feedback is incorporated into the circuit, and from the further fact that the loop gain of the circuit is greater than unity.

CIRCUIT DIAGRAM

MODEL GRAPH:

PROCEDURE:

1 Connect the circuit as per circuit diagram.

2 Apply a sine wave of peak to peak amplitude 10V, 1 KHz frequency wave as input to the circuit.

3 Observe input and output waveforms simultaneously in channel 1 and channel 2 of CRO.

4 Note down the input voltage levels at which output changes the voltage level.

5 Draw the graph between voltage versus time of input and output signals.

VIVA QUESTIONS

1. What is the other name of the Schmitt trigger?
2. What are the applications of the Schmitt trigger?
3. Define the terms UTP & LTP?

RESULT:

                                                                               

          Thus the Schmitt trigger circuit was simulated and verified using multisim software.

10. CURRENT TIME BASE GENERATOR

Ex. No:

Date:     

             

AIM:

            To design, and simulate the Current Time Base Generator using transistor with PSPICE Multisim.

APPARATUS REQUIRED:

S.NO	APPARATUS NAME	RANGE	QUANTITY
1.	PC With PSPICE MULTISIM SOFTWARE		1

THEORY:

RC charging is  fundamentally exponential rather than linear. The ramp is approximately linear only for a initial period short compared with a time constant, i.e., the initial part of the exponential rise. The difficulty with RC charging is that as the voltage across the capacitor increases the voltages difference across the charging resistor decrease, and also the charging current. Hence the capacitor charges at a continually decreasing rate. One way to avoid this difficulty is to charge the capacitor with a constant current source. The circuit (left) replaces the charging resistor of the previous illustration with a (nearly) constant current source formed by the transistors Q2and Q3. Even so the linearity over an increased voltage range is apparent in the computed performance plotted to the right.

PROCEDURE:

1. Open the Multisim software with a new document.
2. Make the connections as per the circuit diagram
3. Obtain a sine wave output. Measure the frequency and amplitude of the sine wave output.
4. Copy the output and paste on a word/paint document.
5. Take Printout and paste on the record note book.

RESULT:

Thus the Current Time Base generator circuit using transistor was designed and simulated with help of PSPICE Multisim software.
CIRCUIT DIAGRAM:

MODEL GRAPH:

            11. VOLTAGE TIME BASE – MILLER SWEEP GENERATOR

Ex. No:

Date:   

AIM:

            To design, and simulate the Voltage Time Base generator using PSPICE Multisim.

APPARATUS REQUIRED:

S.NO	APPARATUS NAME	RANGE	QUANTITY
1.	PC With PSPICE MULTISIM SOFTWARE		1

CIRCUIT DIAGRAM

THEORY

A straightforward approach to generating a ramp voltage is illustrated by the above circuit diagram .A square wave applied to the BJT alternately switches the transistor between saturation and cutoff operation. When the transistor is cutoff the capacitor C1 charges exponentially through R2, with a time constant R2 C1. On the other hand if the transistor is turned on the capacitor discharges rapidly and the transistor saturates. Initially the transistor is biased ON and operates in the saturation region. Thus when there is no input (i.e. V_i = 0 ), the output voltage is zero. Actually its value is equal to V_CE (sat). When gating pulse i.e. a negative pulse is applied the transistor turns OFF. As a result of this, the capacitor voltage rises to a target value V_CC with a time constant R_CC. The charging curve ignoring V_CE (sat) is given by the relation.

If t / R_CC << 1, then above relation may be expanded into a power series in t / R_CC. Then taking only the first term of the power series, the output voltage.

This equation represents an approximately linear waveform. It may be observed that the transistor switch is OFF only for the gating time (T_S). At the end of time T_S, the capacitor discharges and the voltage is again zero.

MODEL GRAPH

PROCEDURE:

6. Open the Multisim software with a new document.
7. Make the connections as per the circuit diagram
8. Obtain a sine wave output. Measure the frequency and amplitude of the sine wave output.
9. Copy the output and paste on a word/paint document.
10. Take Printout and paste on the record note book.

RESULT:

Thus the voltage sweep generator circuit using transistor was designed and simulated with help of PSPICE Multisim software.