scc lab manual

8/2/2019 SCC Lab Manual

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7.1.1 Title of the Experiment: Measurement of Opamp parameters (I/P Offset current, I/P bias

current, Slew rate, I/P offset Voltage, PSRR, CMRR) & offset nulling.

7.1.2 Objective of the Experiment: To conduct an experiment to verify the Op-amp parameters.

7.1.3 List of Component / Equipments:

Sl. noComponent/

EquipmentsSpecification Quantity

1 Regulated DC 0-30V, 2A 02

2 CRO 80 Vpp/20MHz 01

3 Ammeter 0-500nA 02

4 +12V and -12V

power pack

01

5 Op-Amplifier A-741 01

7.1.4 Experimental setup:

Circuit Diagram

7.1.5 Theoretical background for the experiment/validation of the experiment:

Input bias current is defined as the average of the bias current at the inverting and non

inverting terminals of an OPAMP. Input offset current is the difference between the basecurrent at the inverting and non inverting terminals of an OPAMP. Input impedance is the

resistance seen from either terminals when other terminal is connected to the ground.

Output impedance is the equivalent output resistance seen from either terminal when one

terminal is connected to the ground. Output offset voltage is defined as the amount voltage

when both the inputs are grounded.

7.1.6 Formulae-required:

Input bias current (IBI + IB2/2) Input offset current (IB1-IB2)


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7.1.7 Step by step procedure to carry out experiment:

Electrical connections are made as shown in the circuit diagram. Set Vcc=15V To measure input offset current, bias current and offset voltage, equal voltages are

applied to both the input terminals of an OPAMP.

Respective base current shown by the ammeters are noted down,

Average of these two currents will be the input bias current and difference ofrespective base current gives the input offset current.

For finding output offset voltage ground both the input terminals and note down theoutput voltage.

7.1.8 Table of observation:1. Input bias current = nA2. Input offset current = nA3. Output offset voltage = mV

7.1.9 Specimen calculation: --------- Not Applicable ---------

7.1.10 Nature of graph: --------- Not Applicable ---------

7.1.11 Conclusion of the experiment:


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7.2.1 Title of the Experiment: Inverting amplifier & attenuator, noninverting amplifier&

voltage follower

7.2.2 Objective of the Experiment: To design and test the performance Inverting amplifier &

attenuator, noninverting amplifier and voltage follower.


a


Inverting Amplifier

Attenuator

Non-inverting Amplifier

Sl.No Components/Equipments Specifications Quantity




4 +12V and -12V power pack 01


6 Resistor 10K watt CFR

1K watt CFR

02

027 Function generator 0-1MHZ 01

8 BNC Probes 02


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Voltage follower



Voltage Gain = -Rf/R1. (Inverting amplifier)Let required gain be 10.

Assume R1=1kTherefore Rf=10k.

Voltage gain = (1+Rf/R1), (Non-inverting amplifier)

Let required gain = 11.

Assume R1=1k.Therefore Rf=10k.


Electrical connections are made as shown in the circuit diagram. Select Input voltage (Vi) of 1 KHz, 0.5Vpp is given from AFO. Note down the output voltage (Vo). And calculate the gain. Repeat all above steps for verifying other circuits.

7.2.8 Table of observation:

Inverting Amplifier

Input Voltage = Vi = Constant

Output Voltage = Vo = Volts

Voltage gain of the amplifier = V0/Vi = . / . = ..

Attenuator





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Non Inverting amplifier




Voltage follower




7.2.9 Specimen calculation: --------- Not Applicable ---------

7.2.10 Nature of graph:

Inverting amplifier

Non-inverting amplifier

Voltage follower



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7.3.1 Title of the Experiment: Adder, substractor, integrator, differentiator

7.3.2 Objective of the Experiment: To study and verify the performance of Op-amp as Adder,

substractor, integrator, differentiator


7.3.4

Experimental setup:

Adder circuit

Substractor circuit

Sl.No Components/Equipments Specifications Quantity




4 +12V and -12V power pack 01


6 Resistor

10K watt CFR

1K watt CFR

250 watt CFR

100 watt CFR1.5K watt CFR

02 each

7 Capacitors 0.1F ceramic disc

0.01F ceramic disk

01 each

8 Function generator 0-1MHZ 01

9 BNC Probes 02


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Integrator circuit

Differentiator circuit


For an adder and subtractor : In an adder circuit (here an OPAMP is used in invertingmode. Out put is leaner combination of number of input signals i.e., the output is

proportional to the sum of the inputs. Assuming that the inputs applied are Va, Vb & Vc in

volts then the output voltage is given by Vo= -Rf/R (Va + Vb + Vc). Similarly when the

OPAMP is used as a subtractor , the output is proportional to the difference of the inputs

applied. If Va & Vb are applied as input voltages then the output is given by Vo = - Rf/R

(Va Vb).

In these two equations Rf is the feedback resistor connected between the output terminal

and the inverting input terminal and the resistor R is connected between the input terminal

and the input applied voltage.

For Integrator and Differentiator : In an integrator circuit using an OPAMP the outputvoltage is given by Vo+-/R1Cf Int (Vin dt + C), this equation shows that the amplifier

provides an output voltage proportional to thintegral of the input voltage. For example if

the input is a square wave, the output will be a triangular wave. Similarly for

differentiator the output voltage is given by Vo = - Rf C1 d/dt (Vin). This shows that, the

output is proportional to the time derivative of the input. If the input is a sine wave then the

output will be a cosine wave and the differentiator circuit has high gain at high frequencies.

In the above two equations resistor R1 is connected between the input terminal and the

input signal voltage, where as Rf is connected between the output terminal and the

inverting input terminal. Similarly the capacitor Cf is connected between the output

terminal and the inverting input terminal, where as C1 is connected between the input

terminal and the input signal voltage.


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Adder : with Rf = 1 Kohm, R = 1 Kohm,

Gain of the amplifier = - Rf/R = -1.

Then the output voltage Vo is equal to the sum of the i/pt voltages applied.

Subtractor : with Rf = 1 Kohm, R = 1 Kohm,

Gain of the amplifier = - Rf/R = -1.

Then the output voltage Vo is equal to the diff of the i/p voltages applied.

Integrator : Let fo = 1 KHz, Cf = 0.1 Mf

We have fo = 1/ 2 x pi x R1 x Cf,

Then R1 = 1 / 2 x pi x fo x Cf = 1.59 Kohm.

Differentiator : Let fo = 1 KHz, C1 = 0.1 Mf

We have fo = 1/ 2 x pi x Rf x C1,

Then Rf = 1 / 2 x pi x fo x C1 = 1.59 Kohm.

Design of Integrator.Output voltage vo = -(1/R1/Cf) * vin dt +C.0dB frequency fb = 1/(2 * * R1 *Cf).Gain limiting frequency fa = 1/(2 * * Rf * Cf).Let fa = fb/10.

Hence Rf = 10 * R1.

Assume R1 = 100, Cf = 0.1F; Rf = 1k.Hence fa = 1.59kHz & fb = 15.9kHz.

Design of differentiator.

Output voltage = -Rf * C1* d/dt (vin).

0dB frequency fa = 1 / (2 * * Rf * C1).Gain limiting frequency fb = 1 / (2 * * R1 * C1).Select fa equal to highest freq. to be differentiated

Assume C1


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For an adder and substractor circuit:

Give three DC Voltages as the input to the adder circuit let these voltages be denotedby, Va, Vb and Vc;

Then note down the output voltage either using CRO or a Voltmeter.

Check this output voltage value with the calculated output voltage value. Vary these input voltages and then note down the corresponding output voltage and

then calculate the error using the measured and calculated output voltage values.

Similarly for a subtractor circuit give two DC Voltages as the input signal. Let these be, Va and Vb and note that Va > Vb. Then measure the corresponding output voltage and check the calculated output

voltage and then compare these two values and find out the error.

For an Integrator and Differentiator Circuit:

After connecting the circuit as per the diagram and give a square wave input signal.

Then observe the output wave form on the CRO and this output wave form should bea triangular wave for an intigrator circuit.

Measure the voltage and time period of both the input and output voltages. Similarly for a differentiator circuit give the square wave as an input. And observe the output wave form on the CRO. Measure the voltage time period of both the input and output wave form.


For AdderVa in V Vb in V Vc in

V

Cald Vo = - Rf/R (Va+Vb+Vc)

in V

Obsd Vo in

V

Error =

Obsd

Cald

For Substractor

Va in V Vb in V Cald Vo = - Rf/R (Va Vb)

in V

Obsd Vo in V Error = Obsd Cald

For Integrator

Input

Voltage Vin

volts

Input time

period in

ms

Input

frequency in

KHZ

Output

voltage Vo in

Volts

Output time

period in ms

Output

frequency in

KHZ


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For Differentiator

Input

Voltage Vin

volts

Input time

period in

ms

Input

frequency in

KHZ

Output

voltage Vo in

Volts

Output time

period in ms

Output

frequency in

KHZ

7.3.9 Specimen calculation: ----- Not applicable -----


Integrator

Differentiator


Operational amplifiers can be used for a wide range of applications.They range from

amplification of small signal voltages to mathematical operations such as integration &

differentiation of input voltage signals.


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7.4.1 Title of the Experiment: I to V converter & V to I converter.

7.4.2 Objective of the Experiment: To study and design I to V converter & V to I converter and

verify the performance.


Sl. noComponents /


1 Op-Amp A-741 01

2 Resistors 10K watt CFR1K watt CFR

02 each

3 Ammeter 0-50mA 01

4 Power supply 0 30 V, 2A 01

5 ALS power pack +12V and -12V 016 Voltmeter 0-50V 01


I to V converter circuit

V-I Converter circuit


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7.4.6 Formulae-required


For an I to V converter after connecting the circuit the input current is varied in stepsof 1mA and measure the output voltage.

Check this value with the calculated output voltage and find out the error. Similarly for a V to I converter with grounded load, keep the input voltage at

constant value then vary the RL and note down IL and Vo.

Then keep RL constant and vary the input voltage Vin and note down the current IL. The error between the observed and the calculated values should be evaluated.

Same procedure should be followed for a V to I converter with floating load.


With RL = 500 OhmsVin in Volts I in in mA Calcd Vo in

Volts

Obsd Vo in

Volts

Error = Obsd

Calcd

With Vin = 5 Volts

RL in Ohms Obsd IL in mA Calcd IL=

Vin/R1 in mA

Error = Obsd Calcd

With RL = 500 Ohms

Vin in Volts Obsd IL in mA Calcd IL= Vin/R1 in

mA

Error = Obsd

Calcd

7.4.9 Specimen calculation:


Graph for I to V



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7.5.1 Title of the Experiment: Half wave & full wave precision rectifiers

7.5.2 Objective of the Experiment: To study and design of Half wave & full wave precision

rectifiers and verify the performance.


Sl. noComponents /


1 Op-Amp A-741 02

2 Resistors 1K watt CFR 05

3 Diode BY-127 02


5 ALS power pack +12V and -12V 01

6 Voltmeter 0-50V 01

7 AFO 0 1 MHZ 01

8 CRO 01


Non inverting precision rectifier

Half wave rectifier


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Full wave precision rectifier


7.5.6 Formulae-required: Not Applicable


Electrical connections are made as shown in the circuit diagram. The i/p is given from the AFO of required voltage and frequency. The rectified o/p observed on CKO The amplitude of rectified o/p will be equal to half the peak to peak voltage of i/p. Circuit connections are made as per circuit diagram. When diodes D1 & D2 are connected as in 1st circuit the ve half cycle is inverted

&the +ve half cycle remains as it is. So we observe on the CRO that both the cycles

are rectified.

When diodes D1 & D2 are connected as in 2nd circuit the rectified o/p will be alongnegative direction is observed on CRO.

The amplitude of the o/p wave form is noted.7.5.8 Table of observation:

Non Inverting Precision HW-Rectifier

Input

Voltage Vin

volts

Input time

period in

ms

Input

frequency in

KHZ

Output

voltage Vo in

Volts

Output time

period in ms

Output

frequency in

KHZ


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Inverting Precision HW-Rectifier

Input

Voltage Vin

volts

Input time

period in

ms

Input

frequency in

KHZ

Output

voltage Vo in

Volts

Output time

period in ms

Output

frequency in

KHZ

Inverting Precision FW-Rectifier

Input

Voltage Vin

volts

Input time

period in

ms

Input

frequency in

KHZ

Output

voltage Vo in

Volts

Output time

period in ms

Output

frequency in

KHZ

7.5.9 Specimen calculation: . Not Applicable ..


Half wave rectifier

Full Wave rectifier



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7.6.1 Title of the Experiment: Design of low pass filters (Butterworth I & II order).

7.6.2 Objective of the Experiment: To design an low pass filters (Butterworth I & II order) and

verify the response.


Sl. noComponent/




3 Crystal 32.768KHz 01

4 BNCs ---- 03

5 BJT 2N3904 01

6 Resistors

27K, 0.25W, CFR

18K, 0.25W, CFR

2.2K, 0.25W, CFR

10K, 0.25W, CFR

01(each)

7 Capacitors

Inductor

12pF(ceramic disc)

0.001micro/25V,

10H

01(each)



7.6.6 Formulae-required: ---------Not Applicable---------



7.6.9 Specimen calculation: ---------Not Applicable---------




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7.7.1 Title of the Experiment: Design of high pass filters (Butterworth I & II order).

7.7.2 Objective of the Experiment: To Design and test the performance of of high pass filters

(Butterworth I & II order).


Sl. No Component / Equipments Specification Quantity

1 Diodes OA79,1N4007 02 each

2 Resistor 1k 01

3 AFO 1MHz,20Vp-p 01

4 CRO 20MHz,80Vp-p 01

5 DC Power supply 0 30V, 2A 01

6 BNCs 03

7 Capacitors 0.1uF, 10uF 01,01



7.7.6 Formulae-required: ----- Not Applicable -----



1.

7.7.9 Specimen calculation: ----- Not Applicable -----




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7.8.1 Title of the Experiment: Instrumentation amplifier- Design for Different gains

7.8.2 Objective of the Experiment: To design and test the performance of Instrumentation

amplifier- Design for Different gains.


Sl. No Component / Equipments Specification Quantity

1

2

3

4

5

6


Instrumentation Amplifier


7.8.6 Formulae-required: ----- Not Applicable -----


Electrical connections are made as shown in the circuit diagram. The function generator (AFO) is kept at 1 kHz frequency and Vin at 3Vp. The input and output waveforms for both circuits are noted/plotted down.


7.8.9 Specimen calculation: ----- Not Applicable -----



After conducting the experiment we Conclude that the input ac signal is clamped to the

desired DC level by providing the DC bias to the clamping circuit.


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7.9.1 Title of the Experiment: RC phase shift and Wein bridge Oscillators.

7.9.2 Objective of the Experiment: To design and study the performance of RC phase shift and

Wein bridge Oscillators


Sl. noComponents /


1 ALS power supply +12V and -12V, 2A 01

2 Resistors Calculated values to be place 03

3 Capacitors 0.1F 03


5 BNC 01

6 CRO 20 MHz/80Vpp 01

7 Op-amp A-741 01


PC phase shift oscillator

Wein bridge oscillator


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A phase-shift oscillator is a simple sine wave electronic oscillator. It contains an inverting

amplifier, and a feedback filter which 'shifts' the phase by 180 degrees at the oscillation

frequency.

The filter must be designed so that at frequencies above and below the oscillation frequency the

signal is shifted by either more or less than 180 degrees. This results in constructive

superposition for signals at the oscillation frequencies, and destructive superposition for all other

frequencies.

The most common way of achieving this kind of filter is using three cascaded resistor-capacitor

filters, which produce no phase shift at one end of the frequency scale, and a phase shift of 270

degrees at the other end. At the oscillation frequency each filter produces a phase shift of 60

degrees and the whole filter circuit produces a phase shift of 180 degrees.

One of the simplest implementations for this type of oscillator uses an operational amplifier (op-

amp), three capacitors and four resistors, as shown in the diagram.

The mathematics for calculating the oscillation frequency and oscillation criterion for this circuit

are surprisingly complex, due to each R-C stage loading the previous ones. The calculations are

greatly simplified by setting all the resistors (except the negative feedbackresistor) and all the

capacitors to the same values. In the diagram, if R1 = R2 = R3 =R, and C1 = C2 = C3 = C, then

and the oscillation criterion is:

A Wien bridge oscillator is a type of electronic oscillator that generates sine waves without

having any input source. It can output a large range of frequencies. The bridge comprises four

resistors and two capacitors. The circuit is based on a network originally developed by Max Wienin 1891. At that time, Wien did not have a means of developing electronic gain so a workable

oscillator could not be realized. The modern circuit is derived from William Hewlett's 1939

Stanford University master's degree thesis. Hewlett, along with David Packard co-founded

Hewlett-Packard. Their first product was the HP 200A, a precision sine wave oscillator based on

the Wien bridge. The 200A is a classic instrument known for its low distortion.

The frequency of oscillation is given by:
http://en.wikipedia.org/wiki/Sine_wavehttp://en.wikipedia.org/wiki/Electronic_oscillatorhttp://en.wikipedia.org/wiki/Feedbackhttp://en.wikipedia.org/wiki/Phase_%28waves%29http://en.wikipedia.org/wiki/Electronic_filterhttp://en.wikipedia.org/wiki/Operational_amplifierhttp://en.wikipedia.org/wiki/Capacitorhttp://en.wikipedia.org/wiki/Resistorhttp://en.wikipedia.org/wiki/Negative_feedbackhttp://en.wikipedia.org/wiki/Electronic_oscillatorhttp://en.wikipedia.org/wiki/Sine_wavehttp://en.wikipedia.org/wiki/Resistorhttp://en.wikipedia.org/wiki/Capacitorhttp://en.wikipedia.org/wiki/Max_Wienhttp://en.wikipedia.org/wiki/Gainhttp://en.wikipedia.org/wiki/William_Hewletthttp://en.wikipedia.org/wiki/Stanford_Universityhttp://en.wikipedia.org/wiki/David_Packardhttp://en.wikipedia.org/wiki/Hewlett-Packardhttp://en.wikipedia.org/wiki/Distortionhttp://en.wikipedia.org/wiki/Distortionhttp://en.wikipedia.org/wiki/Hewlett-Packardhttp://en.wikipedia.org/wiki/David_Packardhttp://en.wikipedia.org/wiki/Stanford_Universityhttp://en.wikipedia.org/wiki/William_Hewletthttp://en.wikipedia.org/wiki/Gainhttp://en.wikipedia.org/wiki/Max_Wienhttp://en.wikipedia.org/wiki/Capacitorhttp://en.wikipedia.org/wiki/Resistorhttp://en.wikipedia.org/wiki/Sine_wavehttp://en.wikipedia.org/wiki/Electronic_oscillatorhttp://en.wikipedia.org/wiki/Negative_feedbackhttp://en.wikipedia.org/wiki/Resistorhttp://en.wikipedia.org/wiki/Capacitorhttp://en.wikipedia.org/wiki/Operational_amplifierhttp://en.wikipedia.org/wiki/Electronic_filterhttp://en.wikipedia.org/wiki/Phase_%28waves%29http://en.wikipedia.org/wiki/Feedbackhttp://en.wikipedia.org/wiki/Electronic_oscillatorhttp://en.wikipedia.org/wiki/Sine_wave


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3.


Electrical connections are made as per circuit diagram. The designed values of resistors and capacitors are added to the circuit. The output waveform is observed on CRO. Note down the practical values such as output magnitude and frequency. Calculate the theoretical output frequency. And finally calculate the deviations.


RC Phase shift Oscillator

Output Voltage

in volts

Output wave

time T in ms

Practical requency

in KHz= 1/T

Theoratical

Frequency

Error

Wein bridge Oscillator

Output Voltage

in volts

Output wave

time T in ms

Practical requency

in KHz= 1/T

Theoratical

Frequency

Error





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7.10.1 Title of the Experiment: ZCD, Positive voltage level & Negative voltage level detectors.

7.10.2 Objective of the Experiment: To design and study the performance of ZCD, Positive

voltage level & Negative voltage level detectors.







Without Filter:


7.10.10 Nature of graph


Sl.No Item Specification Quantity

1. Diode BY127 04

2. Resistors 2.2k,1k, 4.7k 01 each

3. Capacitors 0.1uF10F, 4.7F, 47F 01 each

4. Step down transformer 6-0-6V, 9-0-9V 01 each

5. CRO 20 MHz,80Vp-p 01

6. DMM 500V/10A/200mA 03

7. DRB 1-1Mohm 01


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7.11.1 Title of the Experiment: Schmitt trigger- Design for different hystersis.

7.11.2 Objective of the Experiment: Design and Testing of Schmitt trigger for a noise margin

+/-12V and dead band of 6V




Schmitt trigger converts on irregular shaped waveform to a square wave or pulse. The i/p

voltage Vin triggers the o/p every time it exceeds certain voltage levels called the

upperthreshold voltage VUT and lower threshold voltage VLT.

When Vo = +Vsat the voltage across R1 is called the upper threshold voltage VUT

VUT=21

1

RR

R

+

(+Vsat)

The i/p voltage Vin must be slightly more positive than V UT in order to cause the o/p Vo

to switch from +Vsat to Vsat .

When Vo=-Vsat

The lower threshold voltage Vlt is given as VLT=21

1

RR

R

+(-Vsat)

Sl.No Item Specification Quantity1. Resistors 300K watt CFR

10K watt CFR

01 each

2. CRO 20 MHz,80Vp-p 01

3. DMM 500V/10A/200mA 03

4. DC Power supply 0 30 V, 2A 01

5. Op-amp A-741 01

6. AFO 0-1MHZ 01

7 BNC 02


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Vin must be slightly more negative than VLT in order to cause Vo to switch from Vsat to

+Vsat.

Thus if threshold voltage VUT & VLT are made larger than i/p noise margin the positive

feedback will eliminate the false o/p transaction.


1. VUT=21

1

RR

R

+(+Vsat)

2. VLT=21

1

RR

R

+(-Vsat)

3. Design Calculation

Given data: Noise margin = 2V, dead band = 6 V, +Vsat= +12V, -Vsat= - 12V


Connections are made as per circuit diagram. The i/p is given in such a way that the o/p switches between +Vsat and Vsat. From the o/p waveform and the i/p waveform the dead band is calculated. Feeding i/p to channel A and o/p to channel B and adjusting CRO to x vin A mode the

hysteresis width is measured.


Input

Voltage Vin

volts

Noise

margin

Dead band

voltage

+Ve Sat

voltage

-ve Saturation

Voltage

Output

frequency in

KHZ





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7.12.1 Title of the Experiment: Design of Astable and Monostable Multivibrator using 555

timer.

7.12.2 Objective of the Experiment: To design and study the performance of Astable and

Monostable Multivibrator using 555 timer.



555 timer as astable multivibrator:

555 Timer as Monostable multivibrator:

Sl.No Item Specification Quantity

1. Regulated Power supply 0-30V 1

2. Resistors 1K watt CFR

500 watt CFR01 each

3. Capacitors 0.1F 01 each

4. CRO 20 MHz,80Vp-p 01

5. BNC 01


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Astable Multivibrator:

Circuit diagram shows how a 555 timer IC is configured to function as an astable

multivibrator. An astable multivibrator is a timing circuit whose 'low' and 'high' states

are both unstable. As such, the output of an astable multivibrator toggles between 'low'

and 'high' continuously, in effect generating a train of pulses. This circuit is therefore

also known as a 'pulse generator' circuit.

In this circuit, capacitor C1 charges through R1 and R2, eventually building up enough

voltage to trigger an internal comparator to toggle the output flip-flop. Once toggled,

the flip-flop discharges C1 through R2 into pin 7, which is the discharge pin. When

C1's voltage becomes low enough, another internal comparator is triggered to toggle

the output flip-flop. This once again allows C1 to charge up through R1 and R2 and the

cycle starts all over again.

C1's charge-up time t1 is given by: t1 = 0.693(R1+R2)C1. C1's discharge time t2 is

given by: t2 = 0.693(R2)C1. Thus, the total period of one cycle is t1+t2 = 0.693

C1(R1+2R2). The frequency f of the output wave is the reciprocal of this period, and istherefore given by: f = 1.44/(C1(R1+2R2)), wherein f is in Hz if R1 and R2 are in

megaohms and C1 is in microfarads.

Monostable Multivibrator:

This circuit diagram shows how a 555 timer IC is configured to function as a basic

monostable multivibrator. A monostable multivibrator is a timing circuit that changes

state once triggered, but returns to its original state after a certain time delay. It got its

name from the fact that only one of its output states is stable. It is also known as a 'one-

shot'.

In this circuit, a negative pulse applied at pin 2 triggers an internal flip-flop that turns

off pin 7's discharge transistor, allowing C1 to charge up through R1. At the same time,

the flip-flop brings the output (pin 3) level to 'high'. When capacitor C1 as charged up

to about 2/3 Vcc, the flip-flop is triggered once again, this time making the pin 3 output

'low' and turning on pin 7's discharge transistor, which discharges C1 to ground. This

circuit, in effect, produces a pulse at pin 3 whose width t is just the product of R1 and

C1, i.e., t=1.1 R1C1.

The reset pin, which may be used to reset the timing cycle by pulling it momentarily

low, should be tied to the Vcc if it will not be used.


1. T1 = 0.693 (Ra + Rb) * Ct charge time of Ct.

2. T2 = 0.693 (Rb * Ct) discharge time of Ct.

3. T = T1 + T 2 total period in seconds.

4. F = 1 / T = 1.44 / ((Ra + (2 * Rb)) * Ct) Frequency in Hertz.

5. D = T 2 / T duty cycle, multiply by 100 to get %..

6. % Duty Cycle = tc/t x 100

= 100

2

X

RBRA

RBRA

+

+

7. T = 1.1RC


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Design a astable multi for a pulse of 1.386ms. Set duty cycle to 75%. Verify the values of RA=1k, RB=0.5k. Connect the circuit as shown in Figure. Measure and capture the waveforms of the input, output and the voltage across thecapacitor. Measure the time period and duty cycle of the output and compare with the theoretical

values.


Design a monostable multi for a pulse of 1.1 ms. Connect the circuit as shown in figure. Using a wire connect trigger input to ground momentarily to trigger the circuit. Since

T is high enough,

You should be able to see the single pulse on the scope screen connected to theoutput. Try a few times until you see the whole pulse and measure the width.

Compare this width (period) with the time period you calculated. Alternatively disconnect the output from the scope and connect to a series circuit

consisting of an LED and a 150 ohm resistor.

Using a wire connect trigger input to ground momentarily to trigger the circuit. Youshould observe LED blink for a short period of time set by the period. Show your

results to your instructor/ lab TA.


Astable Multivibrator:1. TC = .. Sec2. TD = .. Sec3. T= TC + TD = sec4. Frequency = F = 1/T = .. HZ


1. TON = .. Sec2. TOFF = sec3. T = TON + TOFF = .. Sec4.

F = 1 / T = HZ.


1.Astable multivibrator:

2. Monostable multivibrator:


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7.12.10 Nature of graph



7.12.11 Conclusion of the experiment: After conducting the experiment we conclude that,

astable multivibrator is a free running oscillator. And monostable multivibrator has one

stable state, it changes its state when trigger pulse is applied. After some time delay its

output comes back to original state.

scc lab manual

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