Clap Switch

Dissertation submitted in the partial fulfillment for the requirement of the

Award of degree in Bachelor of Technology

In

ELECTRICAL AND ELECTRONICS ENGINEERING

By

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----------------------------------------- 08R41A0----

DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING

MOGHAL COLLEGE OF ENGINEERING TECHNOLOGY(AFFILIATED TO JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY

RECOGNISED BY AICTE )BANDALGUDA, CHANDRANGUTA, HYDERABAD DIST-50005

2011-2012

ACKNOWLEDGEMENTACKNOWLEDGEMENT

A MINI PROJECT REPORT

ON

--------------------------------------------------

The Satisfaction and euphoria that accompany the successful completion of this seminar report “----------------------------------------------------” would be incomplete without the mention of the people who made it possible and under whose constant guide the seminar report was completed.

We profusely thank our principle -------------- Sir for his encouragement and support

throughout the project and for granting permission to do our project work

I am greatly indebted to ---------------------- Head of the Department (H.O.D) of Electrical

and Electronics Engineering and technology for providing us unhindered encouragement in

carrying out the seminar report successfully.

We are greatly indebted to our external guide Mohammed Arshad Ahmad Khan, Project Manager, Innovative Technologies for giving us constant encouragement in

carrying out our project.

Finally our sincere thanks to all other members who were helpful directly or

indirectly in the completion of our project.

.

-------------------------(08--------)

DECLARATION

We hereby declare that the dissertation entitled

“------------------------------------------------------” has been submitted by us in partial

fulfillment of the requirement for the award of degree of BACHELOR OF TECHNOLOGY in Electronics

And Communication Engineering from Moghal College of Engineering & Technology affiliated to

Jawaharlal Nehru Technological University and is record of bonafied work carried out by us under the

guidance of __________________ Department Of E.C.E.

The literature embodied in the project has not been submitted to any other University/Inistitute

for the award of any Degree/Diploma.

-----------------------------(08---)

CONTENTS

Chapter 1 - INTRODUCTION

1.2 Overview

1.2 AIMS

1.3 Objective

Chapter 2- LITERATURE SURVEY

2.1 Objective

2.2 Power Saving

Chapter 3 CIRCUIT DESCRIPTION

Chapter 4- CIRCUIT WORKING

4.1 Short Checker

4.2 Brief Functional Description

Chapter 5- PCB ASSEMBLING

5.1 Schematic Capture

5.2 Photo Engraving and PCB Milling

5.3 Dipping in the Solution Exposed Plating and Coating

5.4 Drilling

5.5 Placing the Components and Soldering

Chapter 6- RESULTS AND DISCUSSION

6.1 Testing

6.2 Advantages and Disadvantages

6.3 Chances of Further Advancement

Chapter 7.CONCLUSION

Design of a Clap Activated Switch

Abstract

Many people move through the corridors and steps in multi storied buildings. It is a circuit that can switch on & off a light, Fan, Radio etc. by the sound of clap. The sound of clap is received by a small microphone that is shown biased by resistor R1 in the circuit. The microphone changes sound wave in to electrical wave which is further amplified by Q1.Transistor Q1 is used as common emitter circuit to amplify weak signals received by the microphone. Amplified output from the collector of transistor Q1 is then feed to the Bistable Multivibrator circuit also known as flip-flop.

    Flip flop circuit is made by using 2 Transistor, in our circuit Q2&Q3. In a flip-flop circuit, at a time only one transistor conduct and other cut off andwhen it gets a trigger pulse from outside source then first transistor is cutoff and 2nd

transistor conducts. Thus output of transistor is either logic-0 or logic-1 and it remains in one state 0 or 1 until it gets trigger pulse from outer source.

    The pulse of clap which is a trigger for flip-flop which makes changes to the output which is complementary (reverse). Output of flip-flop which is in the low current form is unable to drive relay directly so we have used a current amplifier circuit by using Q4 which is a common emitter circuit. Output of Q4 is connected to a Relay (Electromagnetic switch), works like a mechanical switch. With the help of a relay it is easy for connecting other electrical appliance.

    The relay contact is connected to the power line and hence turns on/off any electrical appliance connected all the way through relay.

CHAPTER 1

INTRODUCTION

Overview:

Many people move through the corridors and steps in multi storied buildings. It is a circuit that can switch on & off a light, Fan, Radio etc. by the sound of clap. The sound of clap is received by a small microphone that is shown biased by resistor R1 in the circuit. The microphone changes sound wave in to electrical wave which is further amplified by Q1.Transistor Q1 is used as common emitter circuit to amplify weak signals received by the microphone. Amplified output from the collector of transistor Q1 is then feed to the Bistable Multivibrator circuit also known as flip-flop.

    Flip flop circuit is made by using 2 Transistor, in our circuit Q2&Q3. In a flip-flop circuit, at a time only one transistor conduct and other cut off andwhen it gets a trigger pulse from outside source then first transistor is cutoff and 2nd

transistor conducts. Thus output of transistor is either logic-0 or logic-1 and it remains in one state 0 or 1 until it gets trigger pulse from outer source.

    The pulse of clap which is a trigger for flip-flop which makes changes to the output which is complementary (reverse). Output of flip-flop which is in the low current form is unable to drive relay directly so we have used a current amplifier circuit by using Q4 which is a common emitter circuit. Output of Q4 is connected to a Relay (Electromagnetic switch), works like a mechanical switch. With the help of a relay it is easy for connecting other electrical appliance.

    The relay contact is connected to the power line and hence turns on/off any electrical appliance connected all the way through relay.

AIMS

The aim of this project is Design of clap switch for.To achieve the aim there are several objectives need to be considered.

OBJECTIVE

The objectives are:To study on the overall system requirementsTo design on the operation of the transmitter and receiverTo design build, test and assemble the projectTo generate high quality students that have self-confidence good personality and very co-operativeTo expose on a manufacturing and to improve problem solving skills. To improve our technical knowledge and skills.

CHAPTER 2

LITERATURE SURVEY

2.1Objective

Here is a Circuit for electronics that can switch on & off a light, Fan, Radio etc. by the sound of clap. The main scope of this project is to use the electrical appliances by the sound of a clap.

This chapter will review on the process of development of the clap switch. The review on the process involved is very important to make sure the project will successfully functioned. The processes involved are under constant changes due to unexpected problems and occurred. The Flow of the development of the project is divided into 2, which are the hardware and software. The systems hardware is consisted of the prototype itself and the construction circuit of transmitter and receiver. The software is actually a system that controls the overall operation of the project.

2.2 Power Saving

The experiment Design of a Clap Activated Switch is not an ordinary circuit; by some studies we combined a new circuit which is used to install the clap activated switch. So with the help of our guide we started making knowledge about our circuit. Our next aim was to purchase the components. We did the same without any delay in the next week itself. We thoroughly examined all the components. Made a study about them and by testing we assured that they are in working condition. The components were mounted on the strip board and were wired up.

For a couple of times the circuit showed wrong results, connection mistakes, and experiment continued until we got the indented result. As the circuit was found to be working perfectly it was now safe to fabricate it on a printed circuit board. So we decided to design a PCB for our circuit. Since we are dealing with the PCB for the first time. We give this job to a nearby person who is expert in PCB designing. After designing the PCB we started soldering process. Soldering

of the components took a long time as we were soldering for the first time and we couldn’t afford to make a mistake there.

So we soldered slowly and most carefully trying not to short between components, and after a long time we succeeded in completing it. The circuit was tested randomly and was found to be error free and accurate. The design of clap activated switch was then ready to use. In the next project date we showed our project to our guide.

After this we submitted our project diary to our guide then the date of project presentation was decided and we presented our project in front of the faculties of our college. When the diary was got corrected we submitted the rough copy and then the fair.

SUMMARY OF CHAPTER

In this chapter, the background of the project, the problem statement, objectivesand scope of project/limitation was briefly discussed. The project background that has been stated highlighted utilization the applications for this project. The problem statement of this project has included the stages of this project, on how this project will be developed. The objectives are the most important part to show the main purpose of the project and the scope of limitation has been discussed to know the main field of application for this project.

CHAPTER 3CIRCUIT DESCRIPTION

The mini project circuit is a Design of a Clap Activated Switch. The project gives an easy way to detect the intruder. The circuit requires the following list of components in Table 1.

S.NO: COMPONENTS CONFIGURATION

1 Resistors 15k, 1.5k, 2.2m, 270k, 3.3k, 10k, 27k,

2 Capacitors (electrolytic)

1000mf, 0.1mf, .047mf

3 Strip Board General Board

4 Tranistator BC548, BC 368

5 Transformer 12v/500mA

6 Diode IN4148, IN40077 LED 18 Cond. Mic 19 Relay 1

RESISTORS:

A linear resistor is a two-terminal, linear, passive electronic component that implements electrical resistance as a circuit element. The current flowing through a resistor is in a direct proportion to the voltage across the resistor's terminals. Thus, the ratio of the voltage applied across resistor's terminals to the intensity of current flowing through the resistor is called resistance. This relation is represented with a well-known Ohm's law:

Resistors are common elements of electrical networks and electronic circuits and are ubiquitous in most electronic equipment. Practical resistors can be made of various compounds and films, as well as resistance wire (wire made of a high-resistivity alloy, such as nickel-chrome). Resistors are also implemented within integrated circuits, particularly analog devices, and can also be integrated into hybrid and printed circuits.

The electrical functionality of a resistor is specified by its resistance: common commercial resistors are manufactured over a range of more than 9 orders of magnitude. When specifying that resistance in an electronic design, the required precision of the resistance may require attention to the manufacturing tolerance of the chosen resistor, according to its specific application. The temperature coefficient of the resistance may also be of concern in some precision applications. Practical resistors are also specified as having a maximum power rating which must exceed the anticipated power dissipation of that resistor in a particular circuit: this is mainly of concern in power electronics applications. Resistors with higher power ratings are physically larger and may require heat sinks. In a high voltage circuit, attention must sometimes be paid to the rated maximum working voltage of the resistor.

Practical resistors include a series inductance and a small parallel capacitance; these specifications can be important in high-frequency applications. In a low-noise amplifier or pre-amp the noise characteristics of a resistor may be an issue. The unwanted inductance, excess noise, and temperature coefficient are mainly dependent on the technology used in manufacturing the resistor. They are not normally specified individually for a particular family of resistors manufactured using a particular technology.[1] A family of discrete resistors is also characterized according to its form factor, that is, the size of the device and position of its leads (or terminals) which is relevant in the practical manufacturing of circuits using them.

Units

The ohm (symbol: Ω) is the SI unit of electrical resistance, named after Georg Simon Ohm. An ohm is equivalent to a volt per ampere. Since resistors are specified and manufactured over a very large range of values, the derived units of milliohm (1 mΩ = 10−3 Ω), kilohm (1 kΩ = 103 Ω), and megohm (1 MΩ = 106 Ω) are also in common usage.

The reciprocal of resistance R is called conductance G = 1/R and is measured in Siemens (SI unit), sometimes referred to as a mho. Hence, Siemens is the reciprocal of an ohm: S = Ω − 1. Although the concept of conductance is often used in circuit analysis, practical resistors are always specified in terms of their resistance (ohms) rather than conductance.

Theory of operation

Ohm's lawOhm's law

The behavior of an ideal resistor is dictated by the relationship specified by Ohm's law:

Ohm's law states that the voltage (V) across a resistor is proportional to the current (I), where the constant of proportionality is the resistance (R).

Equivalently, Ohm's law can be stated:

This formulation states that the current (I) is proportional to the voltage (V) and inversely proportional to the resistance (R). This is directly used in practical computations. For example, if a 300 ohm resistor is attached across the terminals of a 12 volt battery, then a current of 12 / 300 = 0.04 amperes (or 40 milliamperes) occurs across that resistor.

Series and parallel resistors

In a series configuration, the current through all of the resistors is the same, but the voltage across each resistor will be in proportion to its resistance. The potential difference (voltage) seen across the network is the sum of those voltages, thus the total resistance can be found as the sum of those resistances:

As a special case, the resistance of N resistors connected in series, each of the same resistance R, is given by NR.

Resistors in a parallel configuration are each subject to the same potential difference (voltage), however the currents through them add. The conductances of the resistors then add to determine the conductance of the network. Thus the equivalent resistance (Req) of the network can be computed:

The parallel equivalent resistance can be represented in equations by two vertical lines "||" (as in geometry) as a simplified notation. For the case of two resistors in parallel, this can be calculated using:

As a special case, the resistance of N resistors connected in parallel, each of the same resistance R, is given by R/N.

A resistor network that is a combination of parallel and series connections can be broken up into smaller parts that are either one or the other. For instance,

However, some complex networks of resistors cannot be resolved in this manner, requiring more sophisticated circuit analysis. For instance, consider a cube, each edge of which has been replaced by a resistor. What then is the resistance that would be measured between two opposite vertices? In the case of 12 equivalent resistors, it can be shown that the corner-to-corner resistance is 5⁄6 of the individual resistance. More generally, the Y-Δ transform, or matrix methods can be used to solve such a problem.

One practical application of these relationships is that a non-standard value of resistance can generally be synthesized by connecting a number of standard values in series and/or parallel. This can also be used to obtain a resistance with a higher power rating than that of the individual resistors used. In the special case of N identical resistors all connected in series or all connected in parallel, the power rating of the individual resistors is thereby multiplied by N.

Familiarization of IN4007

A semiconductor diode is simply a P-N junction with connecting leads or terminals on the two sides of the p-n junction. A diode is a unidirectional device permitting the easy flow of current in direction but restraining the flow in other direction. The IN4007 is a standard small signal silicon diode used in signal processing. The IN4007 is generally available in a DO- 41 plastic package and is very useful at 60Hz frequency with peak repetitive reverse voltage of 1000V and average rectified forward current 1.0 A . Its storage temperature range is -55 to +175 °C common IN4007 rectifier diode shown in figure.6

Fig. IN4007

Features

• Diffused Junction

• High Current Capability and Low Forward Voltage Drop

• Surge Overload Rating to 30A Peak

• Low Reverse Leakage Current

• Lead Free Finish, Ro-HS Compliant (Note 3)

Characteristics of IN4007

Basic structure

Light Emitting Diode:

A light-emitting diode (LED) is a semiconductor device that emits visible light when an electric current passes through it. The light is not particularly bright, but in most LEDs it is monochromatic, occurring at a single wavelength. The output from an LED can range from red (at a wavelength of approximately 700 nanometers) to blue-violet (about 400 nanometers). An LED consists of two elements of processed material called P-type semiconductors and N-type semiconductors. These two In this elements are placed in direct contact, forming a region called the P-N junction. In this respect, the LED resembles the most other type diode types, but there are Important other differences between the light emitting diode and the normal diodes.

Also, the LED has a large PN-junction area whose shape is tailored to the application. Light Emitting Diodes or LED’s, are among the most widely used of all the types of diodes available. They are the most visible type of diode that emits a fairly narrow bandwidth of either visible colored light, invisible infra-red or laser type light when a forward current is passed through them.

A "Light Emitting Diode" or LED as it is more commonly called, is basically just a specialized type of P-N junction diode, made from a very thin layer of fairly heavily doped semiconductor material. When the diode is Forward Biased, electrons from the semiconductors conduction band combine with holes from the valence band, releasing sufficient energy to produce photons of light. Because of this thin layer a reasonable number of these photons can leave the junction and radiate away producing a colored light output. Light-emitting diode (LED) is a semiconductor light source. LED’s are used as indicator lamps in many devices.

The LED is based on the effect is called electroluminescence and the color of the light is determined by the energy gap of the semiconductor. Like a normal diode, the LED consists of a chip of semi conducting material doped with impurities to create a p-n junction. As in other diodes, current flows easily from the p-side, or anode, to the n-side, or cathode, but not in the reverse direction. Charge-carriers electrons and holes flow into the junction from electrodes with different voltages.

When an electron meets a hole, it falls into a lower energy level, and releases energy in the form of a photon. The wavelength of the light emitted, and therefore its color, depends on the band gap energy of the materials forming the p-n junction

The key advantages of LED-based lighting are its high efficiency, as measured by its light output per unit power input. LEDs are subject to very limited wear and tear if operated at low currents and at low temperatures. LEDs can be very small (smaller than 2 mm2) and are easily populated onto printed circuit boards. Low power requirement that is most types can be operated with battery power supplies. High efficiency that is Most of the power supplied to an LED is converted into radiation in the desired form, with minimal heat production. Long life that is when properly installed, an LED can function for decades.

CAPACITOR:

A capacitor (formerly known as condenser) is a passive electrical component used to store energy in an electric field. The forms of practical capacitors vary widely, but all contain at least two conductors separated by a non-conductor. Capacitors used as parts of electrical systems, for example, consist of metal foils separated by a layer of insulating film.

A capacitor is a passive electronic component consisting of a pair of conductors separated by a dielectric (insulator). When there is a potential difference (voltage) across the conductors, a static electric field develops across the dielectric, causing positive charge to collect on one plate and negative charge on the other plate. Energy is stored in the electrostatic field. An ideal capacitor is characterized by a single constant value, capacitance, measured in farads. This is the ratio of the electric charge on each conductor to the potential difference between them.

Capacitors are widely used in electronic circuits for blocking direct current while allowing alternating current to pass, in filter networks, for smoothing the output of power supplies, in the resonant circuits that tune radios to particular frequencies and for many other purposes.

The capacitance is greatest when there is a narrow separation between large areas of conductor; hence capacitor conductors are often called "plates," referring to an early means of construction. In practice the dielectric between the plates passes a small amount of leakage current and also has an electric field strength limit, resulting in a breakdown voltage, while the conductors and leads introduce an undesired inductance and resistance.

Networks

For capacitors in parallel

Capacitors in a parallel configuration each have the same applied voltage. Their capacitances add up. Charge is apportioned among them by size. Using the schematic diagram to visualize parallel plates, it is apparent that each capacitor contributes to the total surface area.

For capacitors in series

Several capacitors in series.

Connected in series, the schematic diagram reveals that the separation distance, not the plate area, adds up. The capacitors each store instantaneous charge build-up equal to that of every other capacitor in the series. The total voltage difference from end to end is apportioned to each capacitor according to the inverse of its capacitance. The entire series acts as a capacitor smaller than any of its components.

Capacitors are combined in series to achieve a higher working voltage, for example for smoothing a high voltage power supply. The voltage ratings, which are based on plate separation, add up, if capacitance and leakage currents for each capacitor are identical. In such an application, on occasion series strings are connected in parallel, forming a matrix. The goal is to maximize the energy storage of the network without overloading any capacitor.

Non-ideal behavior

Capacitors deviate from the ideal capacitor equation in a number of ways. Some of these, such as leakage current and parasitic effects are linear, or can be assumed to be linear, and can be dealt with by adding virtual components to the equivalent circuit of the capacitor. The usual methods of network analysis can then be applied. In other cases, such as with breakdown voltage, the effect is non-linear and normal (i.e., linear) network analysis cannot be used, the effect must be dealt with separately. There is yet another group, which may be linear but invalidate the assumption in the analysis that capacitance is a constant. Such an example is temperature dependence.

Types of capacitor

Practical capacitors are available commercially in many different forms. The type of internal dielectric, the structure of the plates and the device packaging all strongly affect the characteristics of the capacitor, and its applications.

Values available range from very low (picofarad range; while arbitrarily low values are in principle possible, stray (parasitic) capacitance in any circuit is the limiting factor) to about 5 kF supercapacitors.

Above approximately 1 microfarad electrolytic capacitors are usually used because of their small size and low cost compared with other technologies, unless their

relatively poor stability, life and polarised nature make them unsuitable. Very high capacity supercapacitors use a porous carbon-based electrode material.

Dielectric materials

Capacitor materials. From left: multilayer ceramic, ceramic disc, multilayer polyester film, tubular ceramic, polystyrene, metalized polyester film, aluminum electrolytic. Major scale divisions are in centimetres.

Most types of capacitor include a dielectric spacer, which increases their capacitance. These dielectrics are most often insulators. However, low capacitance devices are available with a vacuum between their plates, which allows extremely high voltage operation and low losses. Variable capacitors with their plates open to the atmosphere were commonly used in radio tuning circuits. Later designs use polymer foil dielectric between the moving and stationary plates, with no significant air space between them.

In order to maximise the charge that a capacitor can hold, the dielectric material needs to have as high a permittivity as possible, while also having as high a breakdown voltage as possible.

Several solid dielectrics are available, including paper, plastic, glass, mica and ceramic materials. Paper was used extensively in older devices and offers relatively high voltage performance. However, it is susceptible to water absorption, and has been largely replaced by plastic film capacitors. Plastics offer better stability and aging performance.

Ceramic capacitors are generally small, cheap and useful for high frequency applications, although their capacitance varies strongly with voltage and they age poorly. They are broadly categorized as class 1 dielectrics, which have predictable variation of capacitance with temperature or class 2 dielectrics, which can operate

at higher voltage. Glass and mica capacitors are extremely reliable, stable and tolerant to high temperatures and voltages, but are too expensive for most mainstream applications. Electrolytic capacitors and supercapacitors are used to store small and larger amounts of energy, respectively, ceramic capacitors are often used in resonators, and parasitic capacitance occurs in circuits wherever the simple conductor-insulator-conductor structure is formed unintentionally by the configuration of the circuit layout.

Electrolytic capacitors use an aluminum or tantalum plate with an oxide dielectric layer. The second electrode is a liquid electrolyte, connected to the circuit by another foil plate. Electrolytic capacitors offer very high capacitance but suffer from poor tolerances, high instability, gradual loss of capacitance especially when subjected to heat, and high leakage current. Poor quality capacitors may leak electrolyte, which is harmful to printed circuit boards. The conductivity of the electrolyte drops at low temperatures, which increases equivalent series resistance. While widely used for power-supply conditioning, poor high-frequency characteristics make them unsuitable for many applications. Electrolytic capacitors will self-degrade if unused for a period (around a year), and when full power is applied may short circuit, permanently damaging the capacitor and usually blowing a fuse or causing arcing in rectifier tubes. They can be restored before use (and damage) by gradually applying the operating voltage, often done on antique vacuum tube equipment over a period of 30 minutes by using a variable transformer to supply AC power. Unfortunately, the use of this technique may be less satisfactory for some solid state equipment, which may be damaged by operation below its normal power range, requiring that the power supply first be isolated from the consuming circuits. Such remedies may not be applicable to modern high-frequency power supplies as these produce full output voltage even with reduced input.

Tantalum capacitors offer better frequency and temperature characteristics than aluminum, but higher dielectric absorption and leakage.[21] OS-CON (or OC-CON) capacitors are a polymerized organic semiconductor solid-electrolyte type that offer longer life at higher cost than standard electrolytic capacitors.

Several other types of capacitor are available for specialist applications. Supercapacitors store large amounts of energy. Supercapacitors made from carbon aerogel, carbon nanotubes, or highly porous electrode materials, offer extremely high capacitance (up to 5 kF as of 2010) and can be used in some applications instead of rechargeable batteries. Alternating current capacitors are specifically designed to work on line (mains) voltage AC power circuits.

They are commonly used in electric motor circuits and are often designed to handle large currents, so they tend to be physically large. They are usually ruggedly packaged, often in metal cases that can be easily grounded/earthed. They also are designed with direct current breakdown voltages of at least five times the maximum AC voltage.

ELECTROLYTIC CAPCITOR

An electrolytic capacitor is a type of capacitor that uses an electrolyte, an ionic conducting liquid, as one of its plates, to achieve a larger capacitance per unit volume than other types. They are often referred to in electronics usage simply as "electrolytics"[citation needed]. They are used in relatively high-current and low-frequency electrical circuits, particularly in power supply filters, where they store charge needed to moderate output voltage and current fluctuations in rectifier output. They are also widely used as coupling capacitors in circuits where AC should be conducted but DC should not. There are two types of electrolytics; aluminum and tantalum.

Electrolytic capacitors are capable of providing the highest capacitance values of any type of capacitor[citation needed] but they have drawbacks which limit their use. The

standard design requires that the applied voltage must be polarized; one specified terminal must always have positive potential with respect to the other. Therefore they cannot be used with AC signals without a DC polarizing bias. However there are special non-polarized electrolytic capacitors for AC use which do not require a DC bias. Electrolytic capacitors also have relatively low breakdown voltage, higher leakage current and inductance, poorer tolerances and temperature range, and shorter lifetimes compared to other types of capacitors.

Construction

Aluminum electrolytic capacitors are constructed from two conducting aluminum foils, one of which is coated with an insulating oxide layer, and a paper spacer soaked in electrolyte. The foil insulated by the oxide layer is the anode while the liquid electrolyte and the second foil acts as the cathode. This stack is then rolled up, fitted with pin connectors and placed in a cylindrical aluminum casing. The two most popular geometries are axial leads coming from the center of each circular face of the cylinder, or two radial leads or lugs on one of the circular faces. Both of these are shown in the picture

Aluminum electrolytic capacitor: compact but lossy, these are available in the range of <1 µF to 1 F with working voltages up to several hundred volts DC. The dielectric is a thin layer of aluminum oxide. They contain corrosive liquid and can burst if the device is connected backwards. The oxide insulating layer will tend to deteriorate in the absence of a sufficient rejuvenating voltage, and eventually the capacitor will lose its ability to withstand voltage if voltage is not applied. A capacitor to which this has happened can often be "reformed" by connecting it to a voltage source through a resistor and allowing the resulting current to slowly restore the oxide layer.[9] Bipolar electrolytics (also called Non-Polarised or NP capacitors) contain two capacitors connected in series opposition and are used when one electrode can be either positive or negative relative to the other at different instants. Bad frequency and temperature characteristics make them unsuited for high-frequency applications. Typical ESL values are a few nanohenries.

BC 548

BC548 is general purpose silicon, NPN, bipolar junction transistor. It is used for amplification and switching purposes. The current gain may vary between 110 and 800. The maximum DC current gain is 800. Its equivalent transistors are 2N3904 and 2SC1815. These equivalent transistors however have different lead assignments. The variants of BC548 are 548A, 548B and 548C which vary in range of current gain and other characteristics.

 The transistor terminals require a fixed DC voltage to operate in the desired region of its characteristic curves. This is known as the biasing. For amplification applications, the transistor is biased such that it is partly on for all input conditions. The input signal at base is amplified and taken at the emitter. BC548 is used in common emitter configuration for amplifiers. The voltage divider is the commonly used biasing mode. For switching applications, transistor is biased so that it remains fully on if there is a signal at its base. In the absence of base signal, it gets completely off.

Condenser microphone (mic)

Condenser microphone (mic) is a transducer that uses a capacitor (or condenser) to convert acoustical energy into electrical energy. The sound waves result into electric signals that can be used to drive a circuit or device. The pin connected to the case of mic is connected to ground and the other pin gives the output.

A simple capacitor has two plates with a voltage difference between them. The capacitance depends on the distance between these plates. In condenser mic, a diaphragm (of light material) acts as one of the plates. When sound waves strike the diaphragm, the distance, between the plates, changes and so does the capacitance. When the plates come closer, thereby increasing the capacitance, a charge current is generated. Similarly, the capacitance decreases and a discharge current occur when the plates move apart.

There are two methods of extracting sound signals from mic, namely, DC biased and radio frequency (RF). In DC biased method, the charge within the capsule, i.e., diaphragm and fixed plate assembly, remains constant. The voltage variations, across the capsule, are passed through a series resistor and are further amplified. In RF method either the capacitance change modulates the amplitude of output of a low RF oscillator or the capsule is a part of a resonant circuit which modulates the frequency of output. 

Transformer

Transformers convert AC

electricity from one voltage to

another with little loss of power.

Transformers work only with AC

and this is one of the reasons why

mains electricity is AC.

Step-up transformers

increase voltage, step-down

transformers reduce voltage. Most

power supplies use a step-down

transformer to reduce the

dangerously high mains voltage

(230V in UK) to a safer low voltage. The input coil is called the primary and the

output coil is called the secondary.

There is no electrical connection between the two coils; instead they are

linked by an alternating magnetic field created in the soft-iron core of the

transformer. The two lines in the middle of the circuit symbol represent the core.

Transformers waste very little power so the power out is (almost) equal to

the power in. Note that as voltage is stepped down current is stepped up.

The ratio of the number of turns on each coil, called the turn’s ratio,

determines the ratio of the voltages. A step-down transformer has a large number of turns on its

primary (input) coil which is connected to the high voltage mains supply, and a small number of

turns on its secondary (output) coil to give a low output voltage.

Transformer

circuit symbol

Figure 1.7 Transformer & circuit symbol

  turns ratio = Vp

 = Np

   and   power out = power in   

Vs Ns Vs × Is = Vp × Ip

Vp = primary (input) voltage

Np = number of turns on primary coil

Ip  = primary (input) current

Vs = secondary (output) voltage

Ns = number of turns on secondary coil

Is  = secondary (output) current

Relay

A relay is an electrically operated switch. Current flowing through the coil of the relay creates a magnetic field which attracts a lever and changes the switch contacts. The coil current can be on or off so relays have two switch positions and most have double throw (changeover) switch contacts as shown in the diagram.

Fig. Relay

Relays allow one circuit to switch a second circuit which can be completely separate from the first. For example a low voltage battery circuit can use a relay to switch a 230V AC mains circuit. There is no electrical connection inside the relay between the two circuits, the link is magnetic and mechanical.

Fig. Basic Relay Structure

The coil of a relay passes a relatively large current, typically 30mA for a 12V relay, but it can be as much as 100mA for relays designed to operate from lower voltages. Most ICs (chips) cannot provide this current and a transistor is usually used to amplify the small IC current to the larger value required for the relay coil. The maximum output current for the popular 555 timer IC is 200mA so these devices can supply relay coils directly without amplification.

Switch contact arrangement (SPDT, DPDT etc) 

Relays are usually SPDT or DPDT which are often described as "single pole changeover" (SPCO) or "double pole changeover" (DPCO) but they can have many more sets of switch contacts, for example relays with 4 sets of changeover contacts are readily available. Most relays are designed for PCB mounting but you can solder wires directly to the pins providing to take care to avoid melting the plastic case of the relay.

Protection diodes for relays

Relay coils produce brief high voltage 'spikes' when they are switched off and this can destroy transistors and ICs in the circuit. To prevent damage you must connect a protection diode across the relay coil.

Fig. Relay with Protection Diode

Transistors and ICs must be protected from the brief high voltage produced when a relay coil is switched off. The diagram shows how a signal diode (eg 1N4007) is connected 'backwards' across the relay coil to provide this protection.

Current flowing through a relay coil creates a magnetic field which collapses suddenly when the current is switched off. The sudden collapse of the magnetic field induces a brief high voltage across the relay coil which is very likely to damage transistors and ICs. The protection diode allows the induced voltage to drive a brief current through the coil (and diode) so the magnetic field dies away quickly rather than instantly. This prevents the induced voltage becoming high enough to cause damage to transistors and ICs. 

The relay's switch connections are usually labeled COM, NC and NO:

COM = Common, always connect to this, it is the moving part of the switch.

NC = Normally Closed, COM is connected to this when the relay coil is off.

NO = Normally Open, COM is connected to this when the relay coil is on.

Connect to COM and NO if you want the switched circuit to be on when the relay coil is on.

Connect to COM and NC if you want the switched circuit to be on when the relay coil is off.

Fig. relay top view

Choosing a relay

You need to consider several features when choosing a relay:

1.Physical size and pin arrangement 

If you are choosing a relay for an existing PCB you will need to ensure that its dimensions and pin arrangement are suitable. You should find this information in the supplier's catalogue.

2.Coil voltage 

The relay's coil voltage rating and resistance must suit the circuit powering the relay coil. Many relays have a coil rated for a 12V supply but 5V and 24V relays are also readily available. Some relays operate perfectly well with a supply voltage which is a little lower than their rated value.

3. Coil resistanceThe circuit must be able to supply the current required by the relay coil. You can use Ohm's law to calculate the current:

For example: A 12V supply relay with a coil resistance of 400  passes a current of 30mA. This is OK for a 555 timer IC (maximum output current 200mA), but it is too much for most ICs and they will require a transistor to amplify the current.

5. Switch ratings (voltage and current) 

The relay's switch contacts must be suitable for the circuit they are to control. You will need to check the voltage and current ratings. Note that the voltage rating is usually higher for AC, for example: "5A at 24V DC or 125V AC".

Advantages of relays:

Relays can switch AC and DC, transistors can only switch DC. Relays can switch higher voltages than standard transistors.

Relays are often a better choice for switching large currents (> 5A).

Relays can switch many contacts at once.

Disadvantages of relays:

Relays are bulkier than transistors for switching small currents. Relays cannot switch rapidly (except reed relays), transistors can switch many times per second.

Relays use more power due to the current flowing through their coil.

Relays require more current than many ICs can provide, so a low power transistor may be needed to switch the current for the relay's coil.

It is often desirable or essential to isolate one circuit electrically from another, while still allowing the first circuit to control the second.  For example, if you wanted to control a high-voltage circuit from your computer, you would probably not want to connect it directly to a low-voltage port on the back of your computer in case something went wrong and the mains electricity ended up destroying the expensive parts inside your computer.

One simple method of providing electrical isolation between two circuits is to place a relay between them, as shown in the circuit diagram of figure 1.  A relay consists of a coil which may be energized by the low-voltage circuit and one or more sets of switch contacts which may be connected to the high-voltage circuit.

CHAPTER 4CIRCUIT WORKING

Brief functional description:

The sound of clap is received by a small microphone that is shown biased by resistor R1 in the circuit. The microphone changes sound wave in to electrical wave which is further amplified by Q1.Transistor Q1 is used as common emitter circuit to amplify weak signals received by the microphone. Amplified output from the collector of transistor Q1 is then feed to the Bistable Multivibrator circuit also known as flip-flop.

    Flip flop circuit is made by using 2 Transistor, in our circuit Q2&Q3. In a flip-flop circuit, at a time only one transistor conduct and other cut off andwhen it gets a trigger pulse from outside source then first transistor is cutoff and 2nd

transistor conducts. Thus output of transistor is either logic-0 or logic-1 and it remains in one state 0 or 1 until it gets trigger pulse from outer source.

The pulse of clap which is a trigger for flip-flop which makes changes to the output which is complementary (reverse). Output of flip-flop which is in the low current form is unable to drive relay directly so we have used a current amplifier circuit by using Q4 which is a common emitter circuit. Output of Q4 is connected to a Relay (Electromagnetic switch), works like a mechanical switch. With the help of a relay it is easy for connecting other electrical appliance.

    The relay contact is connected to the power line and hence turns on/off any electrical appliance connected all the way through relay.

CHAPTER 5STRIP BOARD ASSEMBLING

Strip Board and its types:

The above fig showing a piece of an unused strip board

Strip board is a widely-used type of electronics prototyping board characterized by a 0.1 inch (2.54 mm) regular (rectangular) grid of holes, with wide parallel strips of copper cladding running in one direction all the way across one side of the board. It is usually known by the name Veroboard, which is a trademark, in the UK, of British company Vero Technologies Ltd, & Pixel Print LTD Canada.

In using the board, breaks are made in the tracks, usually around holes, to divide the strips into multiple electrical nodes. With care, it is possible to break between holes to allow for components that have two pin rows only one position apart such as twin row headers for IDCs.

Perf board:

A related product is called perfboard (short for perforated board). This is like a Vero board but each hole has an isolated copper pad rather than a default pattern of copper tracks. Per board is also widely used for electrical prototyping, generally with techniques such as miniature point to point wiring, wire wrapping, or a wiring pencil.

Variations:

Strip board is available from many different vendors. All versions have copper strips on one side. Some are made using printed circuit board etching and drilling techniques, although some have milled strips and punched holes. The original Veroboard used FR-2 synthetic-resin-bonded paper (SRBP) (also known as phenolic board) as the base board material. Some versions of strip board now use higher quality FR-4 (fiberglass-reinforced epoxy laminate) material.

Hole spacing:

Strip board holes are drilled on 0.1 inch (2.54 mm) centers. This spacing allows components having pins with a 0.1 inch (2.54 mm) spacing to be inserted. Compatible parts include DIP ICs, sockets for ICs, some types of connectors, and other devices.

Strip boards have evolved over time into several variants and related products. For example, a larger version using a 0.15 inch (3.81 mm) grid and larger holes is available, but is generally less popular (presumably because it doesn't match up with standard IC pin spacing).

Assemblies:

An example of a populated strip board

The components are usually placed on the plain side of the board, with their leads protruding through the holes. The leads are then soldered to the copper tracks on the other side of the board to make the desired connections, and any excess wire is cut off. The continuous tracks may be easily and neatly cut as desired to form breaks between conductors using a 5 mm twist drill, a hand cutter made for the purpose, or a knife.

Tracks may be linked up on either side of the board using wire. With practice, very neat and reliable assemblies can be created, though such a method is labour-intensive and therefore unsuitable for production assemblies except in very small quantity.

External wire connections to the board are made either by soldering the wires through the holes or, for wires too thick to pass through the holes, by soldering them to specially made pins called Vero pins which fit tightly into the holes. Alternatively, some types of connectors have a suitable pin spacing to be inserted directly into the board.

Cutting strip board tracks:

Most strip board circuits will need to have some tracks cut to break the connection at that point. This is always necessary under ICs, except for the rare cases where opposite pins must be connected. The tracks are cut with a special track cutter tool or a 3mm drill bit.

Places where the tracks must be broken are usually shown with a cross (X). The cuts are made on the underside (copper side) so extra care is needed to identify the correct hole. It is best to cut the track after soldering because the solder joints will make it easier to identify the correct position.

Place the track cutter on the correct hole and twist it to and fro using moderate force. The aim is to break the copper track, not drill a hole through the board! Inspect the cut closely to ensure there is no fine thread of copper left across the break, because even the tiniest piece will conduct.

Comparison with other systems:

Wire wrap:

Strip board is not designed for surface-mount components. For high density prototyping, especially of digital circuits, wire wrap is faster and more reliable than Strip board for experienced personnel.[2]

Breadboard:

Vero board is similar in concept and usage to breadboard, but is cheaper and more permanent—connections are soldered and while some limited reuse may be possible, more than a few cycles of soldering and desoldering are likely to render both the components and the board unusable.

In contrast, breadboard connections are held by friction, and the breadboard can be reused many times. However, a breadboard is not very suitable for prototyping that needs to remain in a set configuration for an appreciable period neither of time nor for physical mock-ups containing a working circuit or for any environment subject to vibration or movement.

Prototype boards

Strip boards have further evolved into a larger class of prototype boards, available in different shapes and sizes, with different conductive trace layouts.

TriPad:

TriPad strip board has strips of copper broken up into three-hole sections

For example, one variant is called a TriPad board. This is similar to strip board, except that the conductive tracks do not run continuously along the board but are broken into sections, each of which spans three holes.

This allows the legs of two or three components to be easily linked together in the circuit conveniently without the need for track breaks to be made. However, in order to link more than three holes together, wire links or bridges must be formed and this can result in a less compact layout than is possible with ordinary strip board.

Other prototype board variants have generic layouts to simplify building prototypes with integrated circuits, typically in DIP shapes, or with transistors (pads forming triangles). In particular, some boards mimic the layout of

breadboards, to simplify moving a non-permanent prototype on a breadboard to a permanent construction on a PCB.

Some types of boards have patterns for connectors on the periphery, like DB9 or IDCC headers; to allow connectors with non-standard pin spacing’s to be easily used.[3] Some come in special physical shapes, to be used to prototype plug-in boards for computer bus systems.

Placing components on strip board and Soldering:

Components are placed on the non-copper side, then the strip board is turned over to solder the component leads to the copper tracks. Strip board layouts are shown from the component side, so the tracks are out of sight under the board. Layouts are normally shown with the tracks running horizontally across the diagram.

Placing components on strip board requires care. The large number of holes means it is very easy to make a mistake! For most small circuits the best method is to very carefully place the IC holder(s) in the correct position and solder in place.

Then you can position all the other components relative to the IC holder(s). Minor position errors left and right will not usually be a problem because the component will still be connected to the correct tracks. However, up and down position errors

must be avoided because just one hole too high or too low will connect the component to the wrong track and therefore the wrong part of the circuit.

Some people like to label the holes with letters (up/down) and numbers (across) to give each hole a 'grid reference' but this still requires careful counting of holes. See that the soldering is done well very carefully so that no short circuit occurs, if any short circuit occurs then there may be a chance of damage in the circuit and its components.

During the soldering one should not use excessive lead which may lead to a bigger solder patch on the board which may later results in a short circuit.

Thus, one has to be careful during the soldering process as it may affect the circuit and also to its result.

CHAPTER 6

RESULTS AND DISCUSSION

Result

Completed the project work and submitted it in front of the project guide. For the purpose of the demonstration, we determined the Design of a Clap Activated Switch in analog and digital form in front of our guide. To determine the Design of a Clap Activated Switch firstly we have to connect the battery terminal with a probe to the circuit board for the power supply in the circuit. We have to see that the entire circuit is supplied with equal amount of power supply from input end to the output section and this can be done through a continuity tester or multi meter. Beginning with the input point of the live wire and proceeding towards its other end LED inside the continuity tester starts glowing during the presence of AC voltage supply at all the ends from ground to top of the circuit board, when ever the breakage point is tested on the board, LED immediately extinguishes due to the non-availability of mains AC voltage supply.

Testing:

Before determining the Design of a Clap Activated Switch, take out any connected load and find out the faulty wire first by continuity method using any multi meter or continuity tester. We need to notice that the power is supplied in the circuit thoroughly in equal amount.

This can be noticed through a multi meter or a continuity tester by placing one of its end to the ground and other end to the top of the circuit. Check the equal power supply at all the connected wires , if we able to notice that the LED bulb inside the continuity tester glows at all the points , then circuit is tested and we can get the desired the output.

Advantages and Disadvantages of Design of a Clap Activated Switch

The major advantage of clap switch is that you can turn something (e.g. a lamp) on and off from any location in the room (e.g. while lying in bed) simply by clapping your hands.

The major is that it generally cumbersome to have to clap one’s hand to turn something on and off and it’s generally seen as simpler for most use cases to use a traditional light switch. The primary application involves an elderly or mobility-impaired person. A clap switch is generally used for a light, television, radio or similar electronic device that the person will want to turn on/off from bed.

Chances of Further Advancement:

This project is developed with single objective but with microcontroller it can be used for many electrical appliance as for one clap for one electrical appliance and for two claps for other other electrical appliances.

CHAPTER 7

CONCLUSION

Conclusion

Hereby we would like to conclude that this circuit is very much useful to switch ON and OFF the household appliances just by clapping hand .This circuit functions on using the sound energy provided by the clap which is converted into electrical energy by condenser mic .This circuit turns on and off a light, a fan, a radio, a t.v. etc using this converted electrical energy which is used to turn on relay (an electronic switch).The circuit presented here is low cost.