Linear integrated circuit

1. KCES’s COEIT, Jalgaon
Department of Electronics and Telecommunication

Subject In-Charge: Asst. Prof. C. S. Thombre (EXTC)
ACADEMIC YEAR: 20 - 20 SEMISTER: I / II
Name of student
Grade
Roll No Date of Performance
Class Date of Completion
Subject
Experiment No Signature

Aim:- Design and test a square wave, triangular wave and saw tooth wave generator using op-amp for
given frequency.
a. observe output waveforms
b. measure output frequency
Apparatus:- CRO, Breadboard, resistance, capacitors, connecting wires, probes etc
Theory:-
Square wave generator
The principle of generating square wave is to force an op-amp to operate in the saturation region. This
circuit is also known as free-running or astable multivibrator because it has two quasi-stable states.





Diagram: circuit of Square wave generator
The fraction ?=
?.
?->?.
of the output is fed back to the non-inverting terminal. Thus the reference voltage
8
??? is ?8
?. And may take values as +?8
??? and −?8
???. The output is also fed back to inverting terminal
after integrating by means of a low-pass RC combination. Whenever input at inverting terminal just
exceeds 8
???, switching takes place resulting in a square wave output.





Diagram: waveforms of Square wave generator

2. KCES’s COEIT, Jalgaon
Department of Electronics and Telecommunication

Subject In-Charge: Asst. Prof. C. S. Thombre (EXTC)
The frequency, (f = 1/T ) is determined by the time it takes the capacitor to charge from−?8
??? to +?8
???.
8
?=8
???+(−?8
???−8
???)A
??
??
W

8
?=8
???−8
???(1+?)A
??
??
W

Now at t=T1, 8
? reaches to +?8
???, thus we get,
8
?(6
5)=?8
???=8
???−8
???(1+?)A
??-
??
W

∴6
5=4%HJ
1+?
1−?

Thus total time period T=26
5
∴6=26
5=4%HJ
1+?
1−?

For 4
5=1.164
6 we have T=2RC.
∴B
?=
1
24%

The output swings from +Vsat to –Vsat so, 8
?(??)=28
???
Design square wave generator for ?
?=__________. Use a 741 op-amp and DC supply voltage = ±???

3. KCES’s COEIT, Jalgaon
Department of Electronics and Telecommunication

Subject In-Charge: Asst. Prof. C. S. Thombre (EXTC)
Triangular or saw tooth wave generator
A triangular wave can be simply obtained by integrating a square wave. It is obvious that the frequency of
both square wave and triangular wave is same but not the amplitude. The difference between the triangular
& saw tooth waveforms is that the rise time of the triangular wave is always equal to its fall time. On the
other hand the saw tooth waveform has unequal rise & fall time. The simplest triangular waveform
generator consist of a two level comparator followed by integrator.







Diagram: circuit of Triangular wave generator






Diagram: waveforms of Triangular wave generator
Lets consider output of comparator A1 8
?
?
is at +8
???. The output of A2 is negative going ramp. When
output of comparator A1 8
?
?
is at −8
???. The output of A2 is positive going ramp. When output of
comparator A1 8
?
?
is at +8
???, voltage at point P is given by
8
?=−8
????+
4
6
4
6+4
7
c+8
???−(−8
????)g
At t=t1, 8
?=0
−8
????=−
4
6
4
7
(+8
???)

4. KCES’s COEIT, Jalgaon
Department of Electronics and Telecommunication

Subject In-Charge: Asst. Prof. C. S. Thombre (EXTC)
At t=t2, when 8
?
?
switches from −8
??? to +8
???
8
????=−
4
6
4
7
(−8
???)=
4
6
4
7
(8
???)
Thus
8
?(??)=+8
????−k−8
????o=2
4
6
4
7
(8
???)
The output switches from −8
???? to +8
???? in T/2 time. Putting the values in the basic integrator equation
8
?=
−1
4%
?8
??@P
8
?(??)=
−1
4
5%
5
?−8
???.@P
?/6
4
=
8
???
4
5%
5
.
6
2


6=24
5%
5
?
?(??)
????

We get
6=
44
64
5%
5
4
7
=
1
B
?

Design triangular wave generator for ?
?=__________. And study its performance. Use a 741 op-amp
and DC supply voltage = ±??? =

5. KCES’s COEIT, Jalgaon
Department of Electronics and Telecommunication

Subject In-Charge: Asst. Prof. C. S. Thombre (EXTC)
Procedure:-
1. Mount all the components on the bread board as per the circuit diagram.
2. Apply the DC voltage of +15V & -15V from power supply.
3. Observe the output and voltage across capacitor on CRO. For saw tooth wave generators, vary
the pot and observe the waveforms.
4. Write voltage amplitude and draw waveforms on graph paper.

Observations:-

Square wave generator

Theoretically


Practically



Saw tooth or triangular wave generator

Theoretically



Practically




Saw tooth wave generator

Case: Pot Position Observation
Center

Towards +Vcc

Towards +Vee


Conclusion: