“Bistale Multivibrator using IC 555”

A Project Report

Submitted in Partial Fulfilments of the Requirement

For the

Diploma, Sem-III IN

ELECTRONICS & COMMUNICATION ENGG.

Prepared By

Patel Kishan R. (106690311028)Patel Alpesh D. (106690311030)Patel Ankit J. (106690311027)

Department of Electronics & Communication Engineering

Savitaben Dahyabhai Patel Polytechnic, Gadha

Mehsana – Visnagar Highway

Post : Gadha

Dist : Mehsana

Certificate

I here by certify that the work, which is being presented as a report

for seminar entitled “Bistable Multivibrator using IC 555”, is an

authentic report of own work of Kishan, Alpesh & Ankit and is

carried out at Savitaben Dahyabhai Patel Polyrechnic,Gadha for the

partial fulfilment of the requirements for the D.E. (EC), Sem-III.

Head,

E.C. Department,

SDPP,Gadha.

ACKNOWLEDGEMENT

Motivations make dreams come true. We thank Prof. Miss. Jalpa Patel and Head of Department of Electronics and Communication who made us dare to dream and for her immense support throughout the course of our project.

We would like to express our gratitude and appreciation to all those who have helped to bring our project to a successful completion. We would like to thank Mr. Jaydeep Patel and Mr. Mayur Jadav project guide for their guidance and timely feedbacks.

We express our sincere gratitude to all the faculty and staff for their whole hearted co-operation and the motivation they have given to us.

Last but not least, we wish to express our gratitude to the driving force, God the almighty for his abundant blessings which this project would not have been successful.

Patel Kishan R.

Patel Alpesh D.

Patel Ankit J.

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INDEX

Sr.No. Title Page No.

1 Introduction 4

2 Circuit Diagram 5

3 Component List 6

4 Working 7

5 Description 8

6 Summary 13

7 Reference 14

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ABSTRACT

The AIM of introducing this project is to impart knowledge of basic electronic devices. Through the study of this project will get, knowledge of construction, working and characteristics of various types of resistors, capacitors, switches & IC. To study of this devices & a project will be helping full to understand the various basic & applies technology for Bistable Multivibrator.

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1. INTRODUCTION

In the final article in this series we will look at the simplest circuit you can build with the 555 IC - the bistable. As the "bi" in its name suggests, the bistable has two stable states, high and low.

The waveforms in figure illustrate the operation of a bistable. Taking the Trigger input low makes the output of the circuit go into the high state. Taking the Reset input low makes the output of the circuit go into the low state.

This type of circuit is ideal for use in an automated model railway system where the train is required to run back and forth over the same piece of track. A push button (or reed switch with a magnet on the underside of the train) would be placed at each end of the track so that when one is hit by the train, it will either trigger or reset the bistable. The output of the 555 would control a DPDT relay which would be wired as a reversing switch to reverse the direction of current to the track, thereby reversing the direction of the train.

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2. CIRCUIT DIAGRAM

PROCESS:

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3. COMPONENT LIST

3.1 Apparatus & Materials

i. D.C. Regulated Power Supply 12 V, 1 no.ii. C.R.O., Double Beam Type, 1 no.

iii. Breadboard.iv. Connecting Wires.

3.2 Components

i. IC 555, 1 no.ii. Carbon Resistors: 1Ω, 2 no.

iii. Capacitors: 1.0 µf, 1 no.iv. Switches: 2 nos.

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4. WORKING

As the "bi" in its name suggests, the bistable has two stable states, high and low.

If the voltage on pin no. 3 is +Vcc, the multivibrator is se and if it zero, the multivibrator (binary) is in reset state.

Pin no. 2 is connected to +Vcc through resistor Rı and pin no. 6 is connected to ground through resistor R2. When set button is pushed momentarily, pin no. 2 gets negative going triggering pulse and the voltage on pin no. 3 becomes +Vcc. This means flip-flop is set. This is one stable state. Now if this set button is pressed again, there is no change in the output state.

When reset button is pressed momentarily, pin no. 6 gets voltage more than ⅔ Vcc. Due to this voltage on pin 3 goes to zero i.e. the binary resets. This is another stable state.

If necessary the relay can be connected from pin no. 3 through the transistor.

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5. DESCRIPTION

5.1 : RESISTOR

Resistor like diodes and relays, are another of the electronic parts.

Resistors “resist” the flow of electrical current. The higher the value of resistance the lower the current will be.

Resistors are color coded. To read the color code of a common 4 band 1k ohm resistor with a 5% tolerance , start at the opposite side of gold tolerance band and read from left to right, rite down the corresponding number of the color chart below for the 1st

color band. To the right of the number, write the corresponding number for the 2nd band. Now multiply that number by the corresponding multiplier number of the 3rd band .

If a resistor has 5 color bands, write the corresponding number of the 3rd band to the right of the 2nd before you multiply by the corresponding number of the multiplier band. If you only have 4 color bands that include a tolerance band, ignore this column and go straight to the multiplier.

The tolerance band is usually gold or silver, but some may have none. Because resistor are not the exact value is indicated by the color bands, manufactures have included a tolerance color band to indicate the accuracy of the resistor. Gold band indicates the resistor is within 5 % of what is indicate. Silver = 10% and None = 20%. Others are shown in the chart below. The 1kΩ resistor in the example may have an actual measurement any where from 950 Ω to 1050 Ω. If the resistor does not have a tolerance band, start from the closest to a lead. This will be the 1st band. If you are unable to read the color band then you will have to use your multimeter. Be sure to zero it out first !

Resistor color codesBand color 1st band 2

Black 0Brown 1

Red 2Orange 3Yellow 4Green 5Blue 6

Violet 7Gray 8White 9GoldSilver

No color

Resistor color codes2nd band 3rd band Multiplexer Tolerance ±%

0 0 11 1 102 2 1003 3 10004 4 100005 5 1000006 6 10000007 7 100000008 8 1000000009 9 1000000000

0.10.01

Tolerance ±%

±1%±2%±%±%

±0.5%±0.25%±0.10%±0.05%

±±5%

±10%±20%

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5.2 : CAPACITOR

This is a measure of a capacitor’s ability to store charge. A large capacitance means that more charge can be stored. Capacitance is measured in farads, symbol F. However 1F is very large, so prefixes are used to show the smaller values.

Three prefixes (multiplier) are used, µ (micro), n (nano) and p (pico):

µ means 10-6 (millionth), so 1000000µF = 1F

n means 10-9 (thousand-millionth), so 1000nF = 1µF p means 10-12 (million-millionth), so 1000pF = 1Nf

There are many types of capacitors:

a) Polarized Capacitors (large values, 1µF +)b) Electrolytic Capacitorsc) Unpolarized Capacitors (small values, up to 1µF)

d) Polystyrene Capacitors

5.3 : SWITCH

In electronics, a switchcircuit, interrupting the current

A switch may be directly manipulated by a human as a control signal to a system, such as a computer keyboard button, or to control power flow in a circuit, such as a switch. Automatically operated switches can be used to control the motions of machines, for example, to indicate that a garage door has reached its full open position or that a machine tool is in a position to accept another work piece. Switches may be operated by process variables such as pressure, temperature, flow, current, voltage, and force, acting as sensors in a process and used to automatically control a system. For example, a thermostat is a temperaturethat is operated by another electrical circuit is called aremotely operated by a motor drive mechanism. Some switches are used to isolate electric power from a system, providing a visible point of isolation that can be padif necessary to prevent accidental oprevent electric shock.

A push switch or push to makecontacts when held in. When the button is released, the non-latching switch.

The other form is push to breaknot pressed, electricity can flow, but when it is pressed the circuit is broken.

switch is an electrical component that can break ancurrent or diverting it from one conductor to another.

A switch may be directly manipulated by a human as a control signal to a system, such as a computer keyboard button, or to control power flow in a circuit, such as a

tomatically operated switches can be used to control the motions of machines, for example, to indicate that a garage door has reached its full open position or that a machine tool is in a position to accept another work piece. Switches may be operated by

rocess variables such as pressure, temperature, flow, current, voltage, and force, acting in a process and used to automatically control a system. For example,

is a temperature-operated switch used to control a heating process. A switch that is operated by another electrical circuit is called a relay. Large switches may be remotely operated by a motor drive mechanism. Some switches are used to isolate electric power from a system, providing a visible point of isolation that can be padif necessary to prevent accidental operation of a machine during maintenance, or to

push to make switch, allows electricity to flow between its two contacts when held in. When the button is released, the circuit is broken. So it is called a

push to break which does the opposite, i.e. when the button inot pressed, electricity can flow, but when it is pressed the circuit is broken.

that can break an electrical or diverting it from one conductor to another.

A switch may be directly manipulated by a human as a control signal to a system, such as a computer keyboard button, or to control power flow in a circuit, such as a light

tomatically operated switches can be used to control the motions of machines, for example, to indicate that a garage door has reached its full open position or that a machine tool is in a position to accept another work piece. Switches may be operated by

rocess variables such as pressure, temperature, flow, current, voltage, and force, acting in a process and used to automatically control a system. For example,

operated switch used to control a heating process. A switch . Large switches may be

remotely operated by a motor drive mechanism. Some switches are used to isolate electric power from a system, providing a visible point of isolation that can be pad-locked

peration of a machine during maintenance, or to

switch, allows electricity to flow between its two is broken. So it is called a

which does the opposite, i.e. when the button is

5.4 : IC 555

The 555 timer IC is angeneration and oscillator applications. The part is still in widespread use, thanks to iease of use, low price and good stability. As of 2003, it is estimated thatare manufactured every year.

In Bistable mode, the 555 timer acts as a basic flipinputs (pins 2 and 4 respectively on a 555) are held high via threshold input (pin 6) is simply grounded. Thus configured, pulling the trigger momentarily to ground acts as a 'set' and transitions the output pistate). Pulling the reset input to ground acts as a 'reset' and transitions the output pin to ground (low state). No capacitors are required in a bistable configuration. Pin 5 (control) is connected to ground via a small(discharge) is left floating.

is an integrated circuit (chip) used in a variety ofapplications. The part is still in widespread use, thanks to i

ease of use, low price and good stability. As of 2003, it is estimated that 1 billionare manufactured every year.

In Bistable mode, the 555 timer acts as a basic flip-flop. The trigger and reset inputs (pins 2 and 4 respectively on a 555) are held high via Pull-up resistorsthreshold input (pin 6) is simply grounded. Thus configured, pulling the trigger momentarily to ground acts as a 'set' and transitions the output pin (pin 3) to Vcc (high state). Pulling the reset input to ground acts as a 'reset' and transitions the output pin to ground (low state). No capacitors are required in a bistable configuration. Pin 5 (control) is connected to ground via a small-value capacitor (usually 0.01 to 0.1 uF); pin 7

of timer, pulse applications. The part is still in widespread use, thanks to its

1 billion units

flop. The trigger and reset up resistors while the

threshold input (pin 6) is simply grounded. Thus configured, pulling the trigger n (pin 3) to Vcc (high

state). Pulling the reset input to ground acts as a 'reset' and transitions the output pin to ground (low state). No capacitors are required in a bistable configuration. Pin 5 (control)

tor (usually 0.01 to 0.1 uF); pin 7

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6. SUMMARY

6.1 : Advantage It is used for counter , shift resistor & memory.

6.2 : Disadvantage Nothing

6.3 : Conclusion After performing this practical, We can study about Bistable Multivibrator of using IC 555’s working and advantage & disadvantage.

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7. REFERENCES

1. R.P.Ajwalia, “ Electronics Devices & Circuits–II ”, Fifth Edition, Atul Prakashan, 2009

2. David A. Bell, “Electronics Devices & Circuits”, Fifth Edition, Oxford University Press

3. www.wikipedia.org