GROUP NO.:_________________

SYNOPSIS

Hybrid Electric Vehicle (HEV)

Submitted by

GUIDED BY ________________________

AIM: -

To design & develop hybrid electric vehicle (HEV).

Abstract :-  

A hybrid electric vehicle (HEV) is a type of hybrid vehicle and electric vehicle which combines a conventional internal combustion engine (ICE) propulsion system with an electric propulsion system. The presence of the electric powertrain is intended to achieve either better fuel economy than a conventional vehicle, or better performance. A variety of types of HEV exist, and the degree to which they function as EVs varies as well. The most common form of HEV is the hybrid electric car, although hybrid electric trucks (pickups and tractors) and buses also exist.

Modern HEVs make use of efficiency-improving technologies. Some varieties of HEVs use their internal combustion engine to generate electricity by spinning an electrical generator (this combination is known as a motor-generator), to either recharge their batteries or to directly power the electric drive motors. Many HEVs reduce idle emissions by shutting down the ICE at idle and restarting it when needed; this is known as a start-stop system.

In parallel hybrids, the ICE and the electric motor are both connected to the mechanical transmission and can simultaneously transmit power to drive the wheels, usually through a conventional transmission.

Power-split hybrids have the benefits of a combination of series and parallel characteristics. As a result, they are more efficient overall, because series hybrids tend to be more efficient at lower speeds and parallel tend to be more efficient at high speeds; however, the power-split hybrid is higher than a pure parallel

Full hybrid, sometimes also called a strong hybrid, is a vehicle that can run on just the engine, just the batteries, or a combination of bothEnergy source

Transformation of sound into electric

Energy

In physics, energy (from the Greek ἐνέργεια - energeia, "activity, operation", from ἐνεργός - energos, "active, working"[1]) is a quantity that can be assigned to every particle, object, and system of objects as a consequence of the state of that particle, object or system of objects. Different forms of energy include kinetic, potential, thermal, gravitational, sound, elastic, light, and electromagnetic energy. The forms of energy are often named after a related force. German physicist Hermann von Helmholtz established that all forms of energy are equivalent - energy in one form can disappear but the same amount of energy will appear in another form. Energy is subject to a conservation law. Energy is a scalar physical quantity. In the International System of Units (SI), energy is measured in joules, but in some fields other units such as kilowatt-hours and kilocalories are also used.

Any form of energy can be transformed into another form. When energy is in a form other than heat, it may be transformed with good or even perfect efficiency, to any other type of energy. In all such energy transformation processes, the total energy remains the same. Energy may not be created nor destroyed. This principle, the conservation of energy, was first postulated in the early 19th century, and applies to any isolated system. According to Noether's theorem, the conservation of energy is a consequence of the fact that the laws of physics do not change over time.

Although the total energy of a system does not change with time, its value may depend on the frame of reference. For example, a seated passenger in a moving airplane has zero kinetic energy relative to the airplane, but non-zero kinetic energy (and higher

Transformations of energy

One form of energy can often be readily transformed into another with the help of a device- for instance, a battery, from chemical energy to electric energy; a dam: gravitational potential energy to kinetic energy of moving water (and the blades of a turbine) and ultimately to electric energy through an electric generator. Similarly, in the case of a chemical explosion, chemical potential energy is transformed to kinetic energy and thermal energy in a very short time. Yet another example is that of a pendulum. At its highest points the kinetic energy is zero and the gravitational potential energy is at maximum. At its lowest point the kinetic energy is at maximum and is equal to the decrease of potential energy. If one (unrealistically) assumes that there is no friction, the conversion of energy between these processes is perfect, and the pendulum will continue swinging forever.

Sound

Sound energy is also a type of wave motion. We are heard by others when we talk because of the sound energy we produce. It is due to the effect of the air molecules vibrating when we talk. The vibrating molecules hit our eardrums, which enable us to hear others talk. Sound energy may be converted into electrical energy for transmission, and later the electrical energy can be converted back into sound energy at the receiving end. An example of such transformations could be seen in the microphone and the loudspeaker.

Sound, like heat energy is easily lost. The transformation of one form of energy into another may be accompanied by losses in the form of sound and/or heat that are often not desirable

The project here is all about Power-Generating Shock Absorber (PGSA). The Power-Generating Shock Absorber (PGSA) converts kinetic energy into electricity through the use of a Linear Motion Electromagnetic System (LMES).

There are at least two entities who have spent time/resources developing this concept: Goldner et al.; and Oxenreider.

An electromagnetic linear generator and regenerative electromagnetic shock absorber is disclosed which converts variable frequency, repetitive intermittent linear displacement motion to useful electrical power.

The innovative device provides for superposition of radial components of the magnetic flux density from a plurality of adjacent magnets to produce a maximum average radial magnetic flux density within a coil winding array. Due to the vector superposition of the magnetic fields and magnetic flux from a plurality of magnets, a nearly four-fold increase in magnetic flux density is achieved over conventional electromagnetic generator designs with a potential sixteen-fold increase in power generating capacity. As a regenerative shock absorber, the disclosed device is capable of converting parasitic displacement motion and vibrations encountered under normal urban driving conditions to a useful electrical energy for powering vehicles and accessories or charging batteries in electric and fossil fuel powered vehicles. The disclosed device is capable of high power generation capacity and energy conversion efficiency with minimal weight penalty for improved fuel efficiency.

Solar power is the conversion of sunlight into electricity, either directly using

photovoltaics (PV), or indirectly using concentrated solar power (CSP). Commercial CSP plants were first developed in the 1980s, and the 354 MW SEGS CSP installation is the largest solar power plant in the world and is located in the Mojave Desert of California. The 80 MW Sarnia Photovoltaic Power Plant in Canada, is the world’s largest photovoltaic plant. Experimental approaches to solar power include concentrated photovoltaics systems, thermovoltaic devices, and space-based solar power.

Solar power is an intermittent energy source, meaning that solar power is not available at all times, and is normally supplemented by storage or another energy source

In the project here is all about Power-Generating Shock Absorber (PGSA). The Power-Generating Shock Absorber (PGSA) converts kinetic energy into electricity through the use of a Linear Motion Electromagnetic System (LMES).

There are at least two entities who have spent time/resources developing this concept: Goldner et al.; and Oxenreider.

image

An electromagnetic linear generator and regenerative electromagnetic shock absorber is disclosed which converts variable frequency, repetitive intermittent linear displacement motion to useful electrical power. The innovative device provides for superposition of radial components of the magnetic flux density from a plurality of adjacent magnets to produce a maximum average radial magnetic flux density within a coil winding array.

Due to the vector superposition of the magnetic fields and magnetic flux from a plurality of magnets, a nearly four-fold increase in magnetic flux density is achieved over conventional electromagnetic generator designs with a potential sixteen-fold increase in power generating capacity. As a regenerative shock absorber, the disclosed device is capable of converting parasitic displacement motion and vibrations encountered under normal urban driving conditions to a useful electrical energy for powering vehicles and accessories or charging batteries in electric and fossil fuel powered vehicles. The disclosed device is capable of high power generation capacity and energy conversion efficiency with minimal weight penalty for improved fuel efficiency.

How it Works

A conventional automotive shock absorber dampens suspension movement to produce a controlled action that keeps the tire firmly on the road. This is done by converting the kinetic energy into heat energy, which is then absorbed by the shock’s oil.

The Power-Generating Shock Absorber (PGSA) converts this kinetic energy into electricity instead of heat through the use of a Linear Motion Electromagnetic System (LMES). The LMES uses a dense permanent magnet stack embedded in the main piston, a switchable series of stator coil windings, a rectifier, and an electronic control system to manage the varying electrical output and dampening load.

The bottom shaft of the PGSA mounts to the moving suspension member and forces the magnet stack to reciprocate within the annular array of stator windings, producing alternating current electricity. That electricity is then converted into direct current through a full-wave rectifier and stored in the vehicle’s batteries.

The electricity generated by each PGSA can then be combined with electricity from other power generation systems (e.g. regenerative braking) and stored in the vehicle’s batteries.

Plug-and-Play

The PGSA is the same basic size and shape, and mounts in the same way, as a standard shock absorber or strut cartridge.

Adjustable Dampening

An electronic control system monitors the requirements of each individual road wheel’s suspension and varies the dampening by quickly switching on or off individual stator coil rings. With all stator coil rings switched on the PGSA produces a strong dampening force which can then be varied for disparate road conditions by switching coils on and off as needed. This provides an added level of benefits in allowing the shock to be very soft in cruising situations (small, high-frequency movements) and instantly change to a sport shock in aggressive cornering situations (longer, lower-frequency movements). Further, the rebound and compression strokes can have different dampening values and application curves depending on performance requirements.

This application could conceivably produce over twenty watts per wheel in normal operation. City driving, with its varying road surface characteristics, as well as stop and go traffic’s font-to-back loading, will generate more power than driving on smooth roads at consistent speeds.

THE SOLAR OPTION: -Solar energy is a very large, inexhaustible source of energy. The power from the sun intercepted by the earth is approximately

1.8*1011MW, which is many thousands of times larger than the present consumption rate on the earth of all commercial energy sources. Thus in principle, solar energy could supply all the present and future energy needs of the world on a continuing basis. This makes it one of the most promising of the unconventional energy sources. In addition to its size, solar energy has two other factors in the favour. Firstly, unlike fossil fuels and nuclear power, it is environmentally clean source of energy. Secondly, it is free and available in adequate quantities in almost all parts of the world where people live. Also it has no heavy mechanical section and is free from noise.However, there are many problems associated with its use, the main problem is that it is dilute source of energy. Even in the hottest regions on the earth, the solar radiations flux available rarely exceeds 1 KW/m, which is a low value for technological utilization.

The second problem associated with the use of solar energy is that its availability varies widely with time. The variation in availability occurs daily because of the day night cycle and also seasonally because of the earth’s orbit around the sun.

To rectify these above problems the solar panel should be such that it always receives maximum intensity of light. For existing solar panels, which are without any control systems typical level of efficiency varies from 10% to 4% - a level that should improve measurably if the present interest continues.

SOLAR PANEL: -

A solar cell uses the photovoltaic effect to convert radiation from the sun into electrical energy. The photovoltaic effect arises when a junction between a metal and a semiconductor or two opposite polarity semiconductors is exposed to electromagnetic radiation, usually in the range near ultra violate to infrared. A forward

voltage appears across the illuminated junction and power can be delivered from it to an external circuit. The p-n junction of whom the cell consists has a relatively large surface area and relatively high efficiency (10.... 15 per cent). Solar cells are fabricated mainly from silicon, gallium arsenide, selenium-cadmium sulphide, and thin-film cadmium sulphide. As part of the radiation is reflected by the surface of the cell, an anti-reflect layer is incorporated to minimize reflection. The absorption coefficient is large for short wavelengths, and smaller for longer wavelengths. The efficiency of solar cells reduces by about one half per cent for each degree centigrade rise in their body temperature, so that most cells must be suitably cooled. Note, however, that this depends to a large extent on the material; gallium arsenide/gallium phosphide, for instance, has optimum efficiency at well over 100°C . The spectral response curve of a silicon cell indicates a useful range of wavelengths between 0.5µm and 1.0µm, peaking at about 800µm.

SOLAR CELLS

A device which gets heated by the sun’s energy is called solar heating device. All the solar heating devices are designed in such a way that they help in collecting as much sunlight as possible. The solar heating devices such as solar cooker, solar water h

eater and solar cells have greatly helped in solving the energy problem, its consumption and future energy demands of our country. Solar energy also reduces our dependence on fossil fuel.

SOLAR CELL

It is a device which converts solar energy directly into electricity. Since solar energy is a light energy so we can say, “Solar cell is a device which converts light energy into electrical energy.”

Solar cells are made by a semiconductors such as silicon and galium. Those solar devices which convert the solar radiation into electricity are called Solar Cells. Before we discuss the solar Cells, we should know the meaning of semi-conductors.

SEMI-CONDUCTORS

1. Semi-conductors are those substances which have very low electrical conductivity. 2. They are neither bad conductors nor good conductors of electricity. 3. They are not good conductors., but unlike an insulator, they

allow Some current to pass through them.

4. Two common semi-conductor are (1) Silicon, (2) Galium.

PROCESS OF TRANSFORMATION OF SOLAR ENERGY INTO ELECTRICAL ENERGY

Solar energy is transformed in the form of electromagnetic radiations of different wavelength. These radiations comprise visible light and invisible light (infra red) Solar cells can transform light energy into electrical energy which can also be converted into mechanical energy.

The conductivity of solar cells, that is ability to conduct

electricity of semi conduct electricity of semi-conductors increases

if certain impurities like Boron and Arsenic are added to them.

These can be explained from following Fig. 1.

Collection Electric Current

Solar Raditions

Flow of Electrons

USE OF SEMI-CONDUCTORS IN SOLAR CELLS

Due to use of semi-conductors materials for making solar

cells, efficiency of solar cells has increased tremendously. The

efficiency of Solar cells has increased tremendously. The

efficiency of solar cells, made from silicon, galium and germanium

is limited upto 10% to 15% that is they can convert about 10% to

15% of solar energy into electrical energy. Efficiency of modern

solar cells mode from selenium is upto 25% which is quite high.

CONSTRUCTION OF SOLAR CELLS

These days solar cells are usually made from semi-conductors like silicon, galium and selenium.

To make a solar cells, wafer (think layer) of semi-conductor materials are arranged in such a way that when the light falls on them, a potential difference is produced between the two regions of wafer (See Fig. 2). When the sunlight falls on wafer of selenium, it is converted into electricity due to emission of electrons.

Solar Radiations Ctric Current

Borona Major impurity Flow of Electrons Arsenic Major impurity

Potential difference produced by a single solar cell of 4 sq

cm size is about 0.4 volts and generates current of 0 milli-

amperes.

SOLAR CELL PANEL

A lot of electricity is required for working of various device such as artificial satellites, water pumps, street lighting, etc. No single cell can provide such energy. But by joining a large number of solar cells in a particular way, we can obtain any amount of electrical energy at any desired voltage. A solar cell panel contains large number of solar cells joined together in a definite pattern. The solar panel converts solar energy into electricity during day. The energy so produced is stored in condensers and is used during nights. A solar panel can provide much more electric power than a single solar cell.

ADVANTAGES OF SOLAR CELL PANEL

1. Solar cell panel provide a large amount of electricity than a single cell. The electricity provided by it is used to run electric motors and lift water from deep wells.

2. The electric power required for working of artificial satellites stationed in outer space. Street lighting in remove areas and running of irrigation water pumps, etc., is obtained with the help of a solar cell panel.

3. Solar cell panel is very helpful to overcome energy crises in the modern times. In Fig. 3 solar energy is being used for running a water pump for irrigation with the help of solar cell panel.

4. There is also a solar cell panel ‘S’ in which hundreds of solar cells are joined together. The electricity produced by solar panel is stored in battery ‘B’. This battery runs the electric motor M and finally motor M drives the pump P, which pumps out the underground water.

APPLICATIONS OF SOLAR CELLS

1. The uses of solar cells have been very effective in providing electric power to remote inaccessible and isolated places.

2. Solar cells are used for providing electricity in artificial satellites and space probes depend mainly on the electricity generated by solar panels. In India, solar cells are being used for street light, for running water pumps and for operating radio and televisions sets in remote areas.

3. Solar cells are used for providing electricity to light houses situated in the sea and to off shore oil drilling rig platforms Solar cells are used for operating electronic watches and calculators. Solar cells have gained a lot of importance in the last few decade because they are being used increasingly for providing electricity to artificial satellites and

space probes, for providing electricity to remote areas and for operating modern instruments, like electronic watches and calculators.

4. In India, efforts are being made to harness solar energy on a large scale to meet its ever-increasing needs for energy.

5. The department of Non-conventional Energy Sources (DNS) of Government of India and similar departments of the State level are making all efforts to popularise use of solar cells of generating electricity. Solar cells and solar panels are available to the public at highly subsidised rates. In order to harness solar energy on a commercial scale, many solar energy parks are being established in India.

6. The greatest advantage of solar energy cells is that they make use of ever-lasting solar energy and their use does not produce any environmental pollution.

This 6 Watt fluorescent tube light (23cm) runs for four hours without electricity. One can use this as emergency light.

The circuit comprises the inverter unit. The 6V DC of the battery is converted into AC by power transistor T-1 (NPN). The output of the transistor is fed to the inverter transformer. Capacitor and Resistor network used for oscillation. Thus, inverter transformer (here used 6-0-6 transformer) steps up 6v DC to 160V AC, which is sufficient for operating a tube light.

In the circuit all the components should be mounted on PCB except X-1 step down transformer. It is used to charge the battery and switch off transistor T-1 by applying reverse bias to its base when 230V AC mains supply is available. Diode D-2 & D-4 provides negative supply to the base of T-1 to make it reverse biased. Capacitor C-2 smooths this negative supply. When the supply fails, T-1 conducts through LC network. The biasing voltage can be varying by R-3. The output from its collector is fed to the primary of inverter transformer. The step-up output is available at secondary of is transformer to glow the tube light.

WORKING

In the given circuit Transformer X1 is used to charge the 6V 4A battery. Diode D1 & D3 provides fullwave rectifier & Capacitor 470f gives ripple filtration across the battery. While charging the 0V of the transformer blocks transistor's biasing (reverse biasing) & not to allow the emergency light to glow while charging. Diode D1 provides reverse biasing for the same purpose to transistor T1. When the main supply is switched off the transistor gets +ve voltage via 4.7k variable - 560 resistance half of primary coil of transformer. The O/P of transistor is coming through collector & other half of the transformer X2. Secondary of transformer is connected to the tube light for high voltage to glow

the tube. The 1st half of transformer also provides feedback to the transistor. Capacitor 0.01f across collector & emitter provides ripple free glow for tube light.

Keeping in time is very important for every human being, that is why many instruments are being used to make the work in discipline order and in time. The timer, as the term is used in digital electronics, is an electronic circuit that once triggered, produces an output pulse for a predetermined time or after a predetermined time and then resets when desired. A simple timer would involve momentarily pressing a button (reset switch) to ‘on’ the device to count the delay time and a variable control to set the required time. After that time interval, the connected device either an alarm circuit or indicating device will ‘on’ for that presented time.

APPLICATION

If one needs few seconds for a particular experiment that he can use this small timer by adjusting the timer required. In photography, the development of film needs variety of time range, from few seconds to minutes.

CIRCUIT DESCRIPTION

This is an electronic switching circuit which will close the contacts of a relay after a certain period of time. This can be adjusted from few second to several minutes. When the circuit is activated, Cl Charges to about two thirds of its full potential and bleeds off through RI preset. When RI is low, the discharge occur at a fast rate. When the value of this resistance is high, to added resistance brings about a slow decay of energy. When the Cl is discharged to a certain point, a pulse occur at the output of Pin-3. This allows current flow through the relay coil, closing its contacts and it works as switching for buzzer* or bulb, which is directly connected with 220V A/C, At the time of pulse occurs the relay, energise and result is an alarm Ground buzzer*. It reset by press the push button. It will reset again & de-energise the relay reset the alarm for further time period adjusted by present RI. The time period given by RI is from 5 Sec. to 3 minute & 50 seconds approx. If one wants to increase to time limits replace IOOk preset to 1 Meg.2 or more for an hour or so.

* OR ONE CAN USE ANY ELECTRICAL APPLIANCE WITH IT FOR SWITCHING

COMPONENTS USED

SEMICONDUCTORS

1. IC-1.............................TIMER

RESISTORS

1. R1..............................100K VARIABLE RESISTANCE2. R2..............................100K

CAPACITOR

1. C1..............................1000f

MISCELLANEOUS

1. 9VDC BATTERY2. RELAY (6VDC, 100

ELECTRONIC TIMER INTRODUCTION : Keeping in time is very important for every human being, that is why many instruments are being used to make the work in discipline order and in time. The timer, as the term is used in digital electronics, is an electronic circuit that once triggered, produces an output pulse for a predetermined time or after a predetermined time and then resets when desired. A simple timer would involve momentarily pressing a button (reset

switch) to ‘on’ the device to count the delay time and a variable control to set the required time. After that time interval, the connected device either an alarm circuit or indicating device will ‘on’ for that presented time.APPLICATION : If one needs few seconds for a particular experiment that he can use this small timer by adjusting the timer required. In photography, the development of film needs variety of time range, from few seconds to minutes. CIRCUIT DESCRIPTION : This is an electronic switching circuit which will close the contacts of a relay after a certain period of time. This can be adjusted from few second to several minutes. When the circuit is activated, Cl Charges to about two thirds of its full potential and bleeds off through RI preset. When RI is low, the discharge occur at a fast rate. When the value of this resistance is high, to added resistance brings about a slow decay of energy. When the Cl is discharged to a certain point, a pulse occur at the output of Pin-3. This allows current flow through the relay coil, closing its contacts and it works as switching for buzzer* or bulb, which is directly connected with 220V A/C, At the time of pulse occurs the relay, energise and result is an alarm Ground buzzer*. It reset by press the push button. It will reset again & de-energise the relay reset the alarm for further time period adjusted by present RI. The time period given by RI is from 5 Sec. to 3 minute & 50 seconds approx. If one wants to increase to time limits replace IOOk preset to 1 Meg.2 or more for an hour or so.* OR ONE CAN USE ANY ELECTRICAL APPLIANCE WITH IT FOR SWITCHINGCOMPONENTS USEDSEMICONDUCTORS : RESISTORS : CAPACITOR : MISCELLANEOUS :1. IC-1..........TIMER 1. R1...100K VR 1. C1......1000f 1. BATTERY......9VDC

2. R2........100K 3. RELAY.....(6VDC, 100

6 VOLTS MOTOR CYCLE BATTERY

We have used a motorcycle lead acid battery. This battery is of 6 volts. Power of this battery is used for glowing tube light when

the power supply is off. Otherwise, the power supply keeps on charging the battery.

NEON LAMP

230 volts neon lamps are connected between 220 volts AC input and transformer. This lamp is working as an indicator. It indicates whether the power is on or off.

FLUORESCENT TUBE LIGHT

A fluorescent 20 watts tube is used as a source of light. The given circuit operates it automatically.

LIGHT DEPENDENT RESISTOR

L.D.R. or light dependent resistor or Photocell is a peculiar type of resistor and is a highly solid state device. Certain material shows less or resistance when light falls on them. The resistance decreases (allowing more current to flow) when placed in light

instead of darkness. So, the internal resistance of L.D.R. is directly controlled by the intensity of light on it. When it is kept in dark the internal resistance is quite high, above 2 Meg and in bright sun light it is 5 k or less. So we can use this L.D.R. in different applications like-to activate the entire circuit depending upon the resistor. It can be alarm, siren or any other device.

These are made in disc shapes with wire lead ends on one side, in sizes 0.3 "diameter upto 1" diameter. These have a ceramic substance on which is deposited a film of cadmium sulphide or cadmium selenite. The track may be formed in a zig zag way to increase the length and hence the resistance value. Depend upon the layer the resistance varies. When light falls on the surface, resistance decreases. Types, which have a 15k down to 600 ohms from dark to light, are available. (Some types have Meg. dark resistance). These are sensitive to visible light only. Power ratings are 50 MW for small types, upto 0.6W for one-inch sizes.

These are useful as light alarms. They are very sensitive even to small light changes. Their response time is a few milliseconds and so they are not good for high-speed light switching measurements.

INTRODUCTION – SUN SEEKER

Energy plays a vital role in almost all the areas of human life. Energy is required to sustain and improve the standard of living. In the present machine age we just cannot imagine life without energy. Today, every country draws its energy needs from a variety of sources.

All energy sources are of consuming nature. For example, thermal power generating station consumes coal in huge quantities, or it may consume fuel at numerous liters. Hydraulic power station would not need raw material, but need water flow; it depends completely on water flow. So when there is no flow of water at required level this station is of no use. The coal or fuel used in thermal power station creates environment pollution by leaving toxic gas output. Then all of these power stations need lot of mechanical sections like turbine and etc. to get power. Even windmills also need mechanical section to produce power.

THE SOLAR OPTION: -Solar energy is a very large, inexhaustible source of energy. The power from the sun intercepted by the earth is approximately

1.8*1011MW, which is many thousands of times larger than the present consumption rate on the earth of all commercial energy sources. Thus in principle, solar energy could supply all the present and future energy needs of the world on a continuing basis. This makes it one of the most promising of the unconventional energy sources. In addition to its size, solar energy has two other factors in the favour. Firstly, unlike fossil fuels and nuclear power, it is environmentally clean source of energy. Secondly, it is free and available in adequate quantities in almost all parts of the world where people live. Also it has no heavy mechanical section and is free from noise.However, there are many problems associated with its use, the main problem is that it is dilute source of energy. Even in the hottest regions on the earth, the solar radiations flux available rarely exceeds 1 KW/m, which is a low value for technological utilization.

The second problem associated with the use of solar energy is that its availability varies widely with time. The variation in availability occurs daily because of the day night cycle and also seasonally because of the earth’s orbit around the sun.

To rectify these above problems the solar panel should be such that it always receives maximum intensity of light. For existing solar panels, which are without any control systems typical level of efficiency varies from 10% to 4% - a level that should improve measurably if the present interest continues.

INTRODUCTION - DC Motor

Faradays used oersteds discovered, that electricity could be used to produce motion, to build the world first electric motor in 1821. Ten years later, using the same logic in reverse, faraday was

interested in getting the motion produced by oersteds experiment to be continuous, rather then just a rotatory shift in position. In his experiments, faraday thought in terms of magnetic lines of force. He visualized how flux lines existing around a current carrying wire and a bar magnet. He was then able to produce a device in which the different lines of force could interact a produce continues rotation. The basic faradays motor uses a free-swinging wire that circles around the end of a bar magnet. The bottom end of the wire is in a pool of mercury. Which allows the wire to rotate while keeping a complete electric circuit.

BASIC MOTOR ACTION

Although Faraday's motor was ingenious. It could not be used to do any practical work. This is because its drive shaft was enclosed and it could only produce an internal orbital motion. It could not transfer its mechanical energy to the outside for deriving an external load. However it did show how the magnetic fields of a conductor and a magnet could be made to interact to produce continuous motion. Faradays motor orbited its wire rotor must pass through the magnet’s lines of force.

When a current is passes through the wire ,circular lines of force are produced around the wire. Those flux lines go in a direction described by the left-hand rule. The lines of force of the magnet go from the N pole to the S pole You can see that on one side of

the wire, the magnetic lines of force are going in the opposite direction as a result the wire, s flux lines oppose the magnet’s flux line since flux lines takes the path of least resistance, more lines concentrate on the other side of the wire conductor, the lines are

bent and are very closely spaced. The lines tend to straighten and be wider spaced. Because of this the denser, curved field pushes the wire in the opposite direction.

The direction in which the wire is moved is determined by the right hand rule. If the current in the wire went in the opposite direction. The direction of its flux lines would reverse, and the wire would be pushed the other way.

Rules for motor action

The left hand rule shows the direction of the flux lines around a wire that is carrying current. When the thumb points in the

direction of the magnetic lines of force. The right hand rule for motors shows the direction that a current carrying wire will be

moved in a magnetic field. When the forefinger is pointed in the direction of the magnetic field lines, and the centre finger is

pointed in the direction of the current in the wire the thumb will point in the direction that the wire will be moved.

TORQUE AND ROTATORY MOTION

In the basic action you just studied the wire only moves in a straight line and stops moving once out of the field even though the current is still on. A practical motor must develop a basic twisting force called torque loop. We can see how torque is produced. If the loop is connected to a battery. Current flows in one direction one side of the loop, and in the opposite direction on the other. Therefore the concentric direction on the two sides.

If we mount the loop in a fixed magnetic field and supply the current the flux lines of the field and both sides of the loop will interact, causing the loop to act like a lever with a force pushing on its two sides in opposite directions. The combined forces result in turning force, or torque because the loop is arranged to piot on its axis. In a motor the loop that moves in the field is called an armature or rotor. The overall turning force on the armature depends upon several factors including field strength armature current strength and the physical construction of the armature especially the distance from the loop sides to the axis lines. Because of the lever action the force on the sides are further from the axis; thus large armature will produce greater torques.

In the practical motor the torque determines the energy available for doing useful work. The greater the torque the greater the

energy. If a motor does not develop enough torque to pull its load it stalls.

Producing Continuous Rotation

The armature turns when torque is produced and torque is produced as long as the fields of the magnet and armature interact. When the loop reaches a position perpendicular to the field, the interaction of the magnetic field stops. This position is known as the neutral plane. In the neutral plane, no torque is produced and the rotation of the armature should stop; however inertia tends to keep a moving object in the motion even after the prime moving force is removed and thus the armature tends to rotate past the neutral plane. But when the armature continues o the sides of the loop start to swing back in to the flux lines, and apply a force to push the sides of the loop back and a torque is developed in the opposite direction. Instead of a continuous rotation an oscillating motion is produced until the armature stops in the neutral plane.

To get continuous rotation we must keep the armature turning in the same direction as it passes through the neutral plane .We

could do this by reversing either the direction of the current flow through the armature at the instant the armature goes through the neutral pole. Current reversals of this type are normally the job of

circuit switching devices. Since the switch would have to be synchronized with the armature, it is more logical to build it into the armature then in to the field. The practical switching device,

which can change the direction of current flow through an armature to maintain continuous rotation, is called a commutator.

THE COMMUTATOR

For the single-loop armature, the commutator is simple. It is a conducting ring that is split into two segment with each segment connected to an end of the armature loop. Power for the armature from an external power source such as a battery is brought to the commutator segments by means of brushes. The arrangement is almost identical to that for the basic dc generator.

The logic behind the operation of the commutator is easy to see in the figures. You can see in figure A that current flows into the side of the armature closest to the South Pole of the field and out of the side closest to the North Pole. The interaction of the two fields produces a torque in the direction indicated, and the armature rotates in that direction.

No torque is produced but the armature continues to rotate past the neutral plane due to inertia. Notice that at the neutral position the commutator disconnects from the brushes sides of the loop reverse positions. But the switching action of the commutator keeps the direction of current flow through the armature the same as it was in the figure. A. Current still flows into the armature side that is now closest to the South Pole.

Since the magnet’s field direction remains the same throughout the interaction of fields after commutation keeps the torque going

in the original direction; thus the same direction of rotation is maintained.

As you can see in figure D, Inertia again carries the armature past neutral to the position shown in the fig. A while communication

keeps the current flowing in the direction that continues to maintain rotation. In this way, the commutator keeps switching the

current through the loop, so that the field it produces always interacts with the pole field to develop a continuous torque in the

same direction.

THE ELEMANTARY D-C MOTOR

At this point, you have been introduced to the four principal parts that make up the elementary D.C motor. These parts are the same as those you met in your study of the basic D.C generator .a magnetic field, a movable conductor, a commutator and brushes. In practice, the magnetic field can be supplied by a permanent magnet or by an electromagnet. For most discussions covering various motor operating principles, we will assume that a permanent magnet is used at other times when it is important for you to understand that the field of the motor is develop electrically, we will show that an electromagnet is used. In either case, the magnetic field itself consists of magnetic flux lines that form a closed magnetic circuit. The flux lines leave the north pole of the magnet, extend across the air gap between the poles of the magnet, enter the South Pole and then travel through the magnet itself back to the north pole. The movable conductor, usually a loop, called armature, therefore is in the magnetic field.

When D.C motor is supplied to the armature through the brushes and commutator, magnetic flux is also build up around the armature. It is this armature flux that interacts with the magnetic field in which the armature is suspended to develop the torque that makes the motor operate.

AIM

TO CONSTRUCT AN AUTOMATICEMERGENCY TUBE LIGHT

INTRODUCTION

Electricity provides the most convenient means of illumination during day and night. Alternative sources of light during sudden power failures are referred to as Emergency Lights. Flash lights (torches), candles, kerosene lamps and petrol/diesel driven generators are widely used to provide an alternative source of light. A common drawback of all these devices is that they have to be located in dark and then operated manually. They are therefore not satisfactory in many practical situations. A sudden failure of light in a jeweller's shop, even for a short duration, can be too costly, and a similar failure in an operation theatre can be disastrous. Hence there is a need for an alternative source of light that comes on automatically, without any significant delay, and goes out by itself when the electrical power is restored. These devices are now commonly referred to as "Emergency Lights". An emergency lightning unit consists of :

(a) A source of electrical energy

(b) A lamp

(c) A sensor to sense absence of main supply and/or absence of illumination

(d) A switch to automatically turn on and off the lamp depending on the output of the sensor/s.

(e) A battery charging circuit (optional).

CIRCUIT DESCRIPTION

With the help of this given circuit, we can run 20-watt fluorescent tube light runs for four hours without electricity.

The circuit can be divided into two parts: The first part consists of the charging unit, which charges the lead - acid battery. The output of step-down transformer XI is converted into DC by four diodes. This output DC voltage charges the lead-acid battery when the power is on. The DC voltage also operates the electromagnetic relay.

The second part of the circuit comprises the inverter unit. The 6V DC of the battery is converted into AC by power transistor

2N3055. The output of the transistor is fed to the inverter transformer. Capacitor C1 and resistor R1 are used for oscillation. Thus inverter transformer steps up 6 volts D.C. to 160 volts A.C., which is sufficient for operating a tube light.

The electromagnetic relay is used for automatic operation of emergency tube light. As soon as the power is cut off, relay operates tube light. When the power comes back, the tube light automatically goes off. It takes about eight hours to get the battery fully charged.

Switch S1 is meant for charging the battery, whereas switch S2 is meant for 'on/off' operation of the emergency tube light. When both S1 and S2 are switched 'on', the light will not glow but battery charging will take place. If power fails, the tube light will automatically switch on. When power return, the tube light automatically switches off.

If power fails during the day and the emergency light is not required, then keep the switch S2 at 'off' position.

All the components, including battery, may be housed in a suitable iron box. The 20W fluorescent tube light can be fitted at desired place and its pins connected directly to the output of inverter transformer.

WORKING

The 220 volts AC power supply is connected with input terminals of a 12-0-12 step down transformer, which step down

this voltage to 12 volts ac. The output terminals of transformer are connected to four diodes for full wave/bridge rectifier. This full wave bridge rectifier rectifies the input voltage to pulsating dc.

This dc voltage is used to operate the electromagnetic relay. The 6 volts 100 ohms relay plays the role of twin switch here. The

circuit consists of two parts:

1) Charging unit.

2) Inverter unit.

CHARGING UNIT:

This unit is responsible for charging of lead acid battery. The input power is used for charging the battery. When the input power is on, only the charging is closed and the inverter circuit is open i.e. , no charge is going in the inverter circuit. This is done with the help of electromagnetic relay.

INVERTER CIRCUIT:

It contains of power transistor 2N 3055, a resistor of 47 ohms, a capacitor of 47 microfarad and an inverter transformer. In this circuit the transistor gets conduct via transformer coil and the output of the transistor is fed to the inverter transformer. Capacitor CI and resistor RI are used for oscillation. Thus, inverter transformer steps up 6V DC to 160V AC, which is sufficient for operating a tube light.

The electromagnetic relay is used for automatic operation of emergency tube light. As soon as the power is cut off, relay operates tube light. When the power comes back, the tube light

automatically goes off. It takes about eight hours to get the battery fully charged. Switch SI is meant for charging the battery, whereas switch S2 is meant for ‘on/off’ operation of the emergency tubelight. When both S1 and S2 are switched ‘on’, the light will not glow but battery charging will take place. If power fail, the tube light will automatically switch on. When power returns, the tube light automatically switches off. If power fails during the day and the emergency light is not required, then keep the switch S2 at ‘off position.

All the components, including battery, may be housed in a suitable iron box. The 20W fluorescent tube light can be fitted at desired place and its pins connected directly to the output of inverter transformer.

COMPONENTS LIST

SEMICONDUCTORS:

1. T-1.......................POWER TRANSISTOR 2N3055 (NPN)

2. D-1-D-4...............SILICON DIODES IN 4001

CAPACITOR:

1. C-1......................1f,80V(DC) CAPACITOR

RESISTOR:

1. R-1.......................75 ,5-WATT RESISTOR.

MISCELLANEOUS:

1. X-1.......................CHARGING TRANSFORMER/9V-0-9V SECONDARY, 1A SECONDARY.

2. X-2.......................INVERTER TRANSFORMER.

3. RLY.......................RELAY 6V 100 .

4. NE........................230V NEON LAMP OR LED FOR MAINS INDICATION.

5. S-1 & S-2.............SPST SWITCHS.

6. B-1.......................BATTERY 6 VOLTS RECHARGEABLE

7. TUBE...................6 WATTS 1 NOS. TUBEPRECAUTIONS

The output voltage terminals of inverter transformer X2 should not be touched, even if the circuit is not connected with AC mains, as these terminals give 160V AC output voltage.

Transistor T1 should be mounted on heatsink and connections should be made very carefully. Otherwise the transistor may get damaged.

The automatic tube light would be ideal for power-starved areas with the following changes:

The charging time may be reduced by using 1.5A, 12V charging transformer, Consequently, the relay should be changed to 12V, 75-ohm type and the diodes to 2A (min.).

When power fails during daytime, S2 will switch-off the light, and the battery will discharge through the secondary of the transformer. This can be avoided by using a double contact relay, instead of the single-contact relay mentioned. The second set of contacts should be N/0 type and connected between the positive of the battery and the positive output of the bridge.

A single DPST switch may replace SI and S2. Distilled water must be added to the battery at least once a week to maintain the prober acid concentration. The terminal should be kept clean by rubbing mustard oil periodically to avoid sulphur-dioxide formation.

POWER SUPPLY

In alternating current the electron flow is alternate, i.e. the electron flow increases to maximum in one direction, decreases back to zero. It then increases in the other direction and then decreases to zero again. Direct current flows in one direction only. Rectifier converts alternating current to flow in one direction only. When the anode of the diode is positive with respect to its cathode, it is forward biased, allowing current to flow. But when its anode is negative with respect to the cathode, it is reverse biased and does not allow current to flow. This unidirectional property of the diode is useful for rectification. A single diode arranged back-to-back might allow the electrons to flow during positive half cycles only and suppress the negative half cycles. Double diodes arranged back-to-back might act as full wave rectifiers as they may allow the electron flow during both positive and negative half cycles. Four diodes can be arranged to make a full wave bridge rectifier. Different types of filter circuits are used to smooth out the pulsations in amplitude of the output voltage from a rectifier. The property of capacitor to oppose any change in the voltage applied across them by storing energy in the electric field of the capacitor and of inductors to oppose any change in the current flowing through them by storing energy in the magnetic field of coil may be utilized. To remove pulsation of the direct current obtained

from the rectifier, different types of combination of capacitor, inductors and resistors may be also be used to increase to action of filtering.

NEED OF POWER SUPPLY

Perhaps all of you are aware that a ‘power supply’ is a primary requirement for the ‘Test Bench’ of a home experimenter’s mini lab. A battery eliminator can eliminate or replace the batteries of solid-state electronic equipment and the equipment thus can be operated by 230v A.C. mains instead of the batteries or dry cells. Nowadays, the use of commercial battery eliminator or power supply unit has become increasingly popular as power source for household appliances like transreceivers, record player, cassette players, digital clock etc.

THEORY

U SE OF DIODES IN RECTIFIERS:

Electric energy is available in homes and industries in India, in the form of alternating voltage. The supply has a voltage of 220V (rms) at a frequency of 50 Hz. In the USA, it is 110V at 60 Hz. For the operation of most of the devices in electronic equipment, a dc voltage is needed. For instance, a transistor radio requires a dc supply for its operation. Usually, this supply is provided by dry cells. But sometime we use a battery eliminator in place of dry cells. The battery eliminator converts the ac voltage into dc voltage and thus eliminates the need for dry cells. Nowadays, almost all-electronic equipment includes a circuit that converts ac voltage of mains supply into dc voltage. This part of the equipment is called Power Supply. In general, at the input of the power supply, there is a power transformer. It is followed by a diode circuit called Rectifier. The output of the rectifier goes to a smoothing filter, and then to a voltage regulator circuit. The rectifier circuit is the heart of a power supply.

RECTIFICATION

Rectification is a process of rendering an alternating current or voltage into a unidirectional one. The component used for rectification is called ‘Rectifier’. A rectifier permits current to flow only during the positive half cycles of the applied AC voltage by eliminating the negative half cycles or alternations of the applied AC voltage. Thus pulsating DC is obtained. To obtain smooth DC power, additional filter circuits are required.

A diode can be used as rectifier. There are various types of diodes. But, semiconductor diodes are very popularly used as rectifiers. A semiconductor diode is a solid-state device consisting of two elements is being an electron emitter or cathode, the other an electron collector or anode. Since electrons in a semiconductor diode can flow in one direction only-from emitter to collector- the diode provides the unilateral conduction necessary for rectification. Out of the semiconductor diodes, copper oxide and selenium rectifier are also commonly used.

FULL WAVE RECTIFIER

It is possible to rectify both alternations of the input voltage by using two diodes in the circuit arrangement. Assume 6.3 V rms (18 V p-p) is applied to the circuit. Assume further that two equal-valued series-connected resistors R are placed in parallel with the ac source. The 18 V p-p appears across the two resistors connected between points AC and CB, and point C is the electrical midpoint between A and B. Hence 9 V p-p appears across each resistor. At any moment during a cycle of vin, if point A is positive relative to C, point B is negative relative to C. When A is negative to C, point B is positive relative to C. The effective voltage in proper time phase which each diode "sees" is in Fig.

The voltage applied to the anode of each diode is equal but opposite in polarity at any given instant.

When A is positive relative to C, the anode of D1 is positive with respect to its cathode. Hence D1 will conduct but D2 will not. During the second alternation, B is positive relative to C. The anode of D2 is therefore positive with respect to its cathode, and D2 conducts while D1 is cut off.

There is conduction then by either D1 or D2 during the entire input-voltage cycle.

Since the two diodes have a common-cathode load resistor RL, the output voltage across RL will result from the alternate conduction of D1 and D2. The output waveform vout across RL, therefore has no gaps as in the case of the half-wave rectifier.

The output of a full-wave rectifier is also pulsating direct current. In the diagram, the two equal resistors R across the input voltage are necessary to provide a voltage midpoint C for circuit connection and zero reference. Note that the load resistor RL is connected from the cathodes to this center reference point C.

An interesting fact about the output waveform vout is that its peak amplitude is not 9 V as in the case of the half-wave rectifier using the same power source, but is less than 4½ V. The reason, of course, is that the peak positive voltage of A relative to C is 4½ V, not 9 V, and part of the 4½ V is lost across R.

Though the full wave rectifier fills in the conduction gaps, it delivers less than half the peak output voltage that results from half-wave rectification.

BRIDGE RECTIFIER

A more widely used full-wave rectifier circuit is the bridge rectifier. It requires four diodes instead of two, but avoids the need for a centre-tapped transformer. During the positive half-cycle of the secondary voltage, diodes D2 and D4 are conducting and diodes D1 and D3 are non-conducting. Therefore, current flows through the secondary winding, diode D2, load resistor RL and diode D4. During negative half-cycles of the secondary voltage, diodes D1 and D3 conduct, and the diodes D2 and D4 do not conduct. The current therefore flows through the secondary winding, diode D1, load resistor RL and diode D3. In both cases, the current passes through the load resistor in the same direction. Therefore, a fluctuating, unidirectional voltage is developed across the load.

Filtration

The rectifier circuits we have discussed above deliver an output voltage that always has the same polarity: but however, this output is not suitable as DC power supply for solid-state circuits. This is due to the pulsation or ripples of the output voltage. This should be removed out before the output voltage can be supplied to any circuit. This smoothing is done by incorporating filter networks. The filter network consists of inductors and capacitors. The inductors or choke coils are generally connected in series with the rectifier output and the load. The inductors oppose any change in the magnitude of a

current flowing through them by storing up energy in a magnetic field. An inductor offers very low resistance for DC whereas; it offers very high resistance to AC. Thus, a series connected choke coil in a rectifier circuit helps to reduce the pulsations or ripples to a great extent in the output voltage. The fitter capacitors are usually connected in parallel with the rectifier output and the load. As, AC can pass through a capacitor but DC cannot, the ripples are thus limited and the output becomes smoothed. When the voltage across its plates tends to rise, it stores up energy back into voltage and current. Thus, the fluctuations in the output voltage are reduced considerable. Filter network circuits may be of two types in general:

CHOKE INPUT FILTER

If a choke coil or an inductor is used as the ‘first- components’ in the filter network, the filter is called ‘choke input filter’. The D.C. along with AC pulsation from the rectifier circuit at first passes through the choke (L). It opposes the AC pulsations but allows the DC to pass through it freely. Thus AC pulsations are largely reduced. The further ripples are by passed through the parallel capacitor C. But, however, a little nipple remains unaffected, which are considered negligible. This little ripple may be reduced by incorporating a series a choke input filters.

CAPACITOR INPUT FILTER

If a capacitor is placed before the inductors of a choke-input filter network, the filter is called capacitor input filter. The D.C. along with AC ripples from the rectifier circuit starts charging the

capacitor C. to about peak value. The AC ripples are then diminished slightly. Now the capacitor C, discharges through the inductor or choke coil, which opposes the AC ripples, except the DC. The second capacitor C by passes the further AC ripples. A small ripple is still present in the output of DC, which may be reduced by adding additional filter network in series.

TRANSFORMER

PRINCIPLE OF THE TRANSFORMER:-

Two coils are wound over a Core such that they are magnetically coupled. The two coils are known as the primary and secondary windings.

In a Transformer, an iron core is used. The coupling between the coils is source of making a path for the magnetic flux to link both the coils. A core as in fig.2 is used and the coils are wound on the limbs of the core. Because of high permeability of iron, the flux path for the flux is only in the iron and hence the flux links both windings. Hence there is very little ‘leakage flux’. This term leakage flux denotes the part of the flux, which does not link both the coils, i.e., when coupling is not perfect. In the high frequency transformers, ferrite core is used. The transformers

may be step-up, step-down, frequency matching, sound output, amplifier driver etc. The basic principles of all the transformers are same.

MINIATURE TRANSFORMER

CONVENTIONAL POWER TRANSFORMER

TRANSISTOR

The name is transistor derived from ‘transfer resistors’ indicating a solid state Semiconductor device. In addition to conductor and insulators, there is a third class of material that exhibits proportion of both. Under some conditions, it acts as an insulator, and under other conditions it’s a conductor. This phenomenon is called Semi-conducting and allows a variable control over electron flow. So, the transistor is semi conductor device used in electronics for amplitude. Transistor has three terminals, one is the collector, one is the base and other is the emitter, (each lead must be connected in the circuit correctly and only then the transistor will function). Electrons are emitted via one terminal and collected on another terminal, while the third terminal acts as a control element. Each transistor has a number marked on its body. Every number has its own specifications.

There are mainly two types of transistor (i) NPN & (ii) PNP

NPN Transistors:

When a positive voltage is applied to the base, the transistor begins to conduct by allowing current to flow through the collector to emitter circuit. The relatively small current flowing through the base circuit causes a much greater current to pass through the emitter / collector circuit. The phenomenon is called current gain and it is measure in beta.

PNP Transistor:

It also does exactly same thing as above except that it has a negative voltage on its collector and a positive voltage on its emitter.

Transistor is a combination of semi-conductor elements allowing a controlled current flow. Germanium and Silicon is the two semi-conductor elements used for making it. There are two types of transistors such as POINT CONTACT and JUNCTION TRANSISTORS. Point contact construction is defective so is now out of use. Junction triode transistors are in many respects analogous to triode electron tube.

A junction transistor can function as an amplifier or oscillator as can a triode tube, but has the additional advantage of long life, small size, ruggedness and absence of cathode heating power.

Junction transistors are of two types which can be obtained while manufacturing.

The two types are: -

1) PNP TYPE: This is formed by joining a layer of P type of germanium to an N-P Junction

2) NPN TYPE: This is formed by joining a layer of N type germanium to a P-N Junction.

Both types are shown in figure, with their symbols for representation. The centre section is called the base, one of the outside sections-the emitter and the other outside section-the collector. The direction of the arrowhead gives the direction of the conventional current with the forward bias on the emitter. The conventional flow is opposite in direction to the electron flow.

OPERATION OF PNP TRANSISTOR:-

A PNP transistor is made by sand witching two PN germanium or silicon diodes, placed back to back. The centre of N-type portion is extremely thin in comparison to P region. The P

P N P

N P N

region of the left is connected to the positive terminal and N-region to the negative terminal i.e. PN is biased in the forward direction while P region of right is biased negatively i.e. in the reverse direction as shown in Fig. The P region in the forward biased circuit is called the emitter and P region on the right, biased negatively is called collector. The centre is called base.

The majority carriers (holes) of P region (known as emitter) move to N region as they are repelled by the positive terminal of battery while the electrons of N region are attracted by the positive terminal. The holes overcome the barrier and cross the emitter junction into N region. As the width of base region is extremely thin, two to five percent of holes recombine with the free electrons of N-region which result in a small base current while the remaining holes (95% to 98%) reach the collector junction. The collector is biased negatively and the negative collector voltage aids in sweeping the hole into collector region.

As the P region at the right is biased negatively, a very small current should flow but the following facts are observed:-

1) A substantial current flows through it when the emitter junction is biased in a forward direction.

2) The current flowing across the collector is slightly less than that of the emitter, and

3) The collector current is a function of emitter current i.e. with the decrease or increase in the emitter current a

corresponding change in the collector current is observed.

The facts can be explained as follows:-

1. As already discussed that 2 to 5% of the holes are lost in recombination with the electron n base region, which result in a

small base current and hence the collector current is slightly less than the emitter current.

2. The collector current increases as the holes reaching the collector junction are attracted by negative potential applied to the collector.

3. When the emitter current increases, most holes are injected into the base region, which is attracted by the negative potential of the collector and hence results in increasing the collector current. In this way emitter is analogous to the control of plate current by small grid voltage in a vacuum triode.

Hence we can say that when the emitter is forward biased and collector is negatively biased, a substantial current flows in both the circuits. Since a small emitter voltage of about 0.1 to 0.5 volts permits the flow of an appreciable emitter current the input power is very small. The collector voltage can be as high as 45 volts.

555 INTEGRATED CIRCUIT(TIMER OPERATION)

The 555 integrated circuit is an extremely versatile timer that can be used in many different applications. This IC is a monolithic timing circuit that is a highly stable controller capable of producing accurate time delays or oscillations. Additional terminals are producing are provided for triggering or resetting if desires. In the time delay mode of resistance and a capacitor. For a stable operation as an oscillator, the free running frequency and the duty cycle are both accurately controlled with two external resistors and one capacitor. The circuit may be triggered and reset on falling waveforms, and the output structure can source or sink up to 200ma or drive TTL Circuits.

This integrated circuit contains nearly 25 transistor, a diode or two, and more than 10 resistors. Obviously, if you built this IC from separate components, it would be many, many times larger than on a monolithic chip.

The 555 timer offers timing from microseconds through hours and operates in both astable and monostable modes. It has an adjustable duty cycle, and the output can drive TTL devices. Its output can operate in normally on and normally off modes and

the IC offers a frequency stability of 0.005% per degrees centigrade.

Applications for the 555 chip include precision timing, pulse generation, pulse width modulation, pulse position modulation, sequential timing, and missing pulse detection.

555-INTEGRATED CIRCUIT

IC 555-ASTABLE OPERATIONS: -

If the circuit is connected as shown in figure (pins 2 and 6 connected). It will trigger itself and free run as a multivibrator. The external capacitor charges through Ra and Rb and discharges through Rb only. Thus, the duty cycle may be precisely set by the ratio of these two resistors. In this mode of operation the capacitor charges and discharges between 1/3 Vcc and 2/3 Vcc. As in the triggered mode, the charge and discharges times, and therefore, the frequency are independent of the supply voltage. Figure shows the actual waveforms generated in this mode of operation.

The charge time (output high) is given by:t1 = 0.685 (Ra + Rb) C

And the discharge time (output low) by:t2 = 0.685 (Rb) C

Thus, the total period is given by:T = t1 + t2 = 0.685 (Ra + 2Rb) C

The frequency of oscillation is then:

f = 1.46 (Ra + 2Rb) C

IC 555-MONOSTABLE OPERATIONS: -

In the monostable mode of operation, the timer functions as

a one shot. Referring to figure the external capacitor is initially held discharged by a transistor inside the timer. Upon applications of a negative trigger pulse to pin 2, the flip-flop is set, which releases the short circuit across the external capacitor and drives the output high. The voltage across the capacitor increases exponentially with the time constant.

t = Ra C

When the voltage across the capacitor equals 2/3 Vcc. The comparator resets the flip-flop, which, in turn, discharges the capacitor rapidly and drives the output to its low state. Figure shows the actual waveforms generated in this mode of operation.

The circuit triggers on a negative going input signal when the level reaches 1/3 Vcc. Once triggered, the circuit will remain in this state until the set time is elapsed, even if it is triggered again during this interval. The time that the output is in the high state is given by: t= 1.1 Ra C

Applying a negative pulse to the reset terminal (pin 4) during the timing cycle discharges the external capacitor and causes the cycle to start over again. The timing cycle will now commence on the positive edge of the reset pulse. During the time the reset pulse is applied, the output is driven to its low state.

DIODE

The simplest semiconductor device is made up of a sandwich of P-type semiconducting material, with contacts

provided to connect the p-and n-type layers to an external circuit. This is a junction Diode. If the positive terminal of the battery is

connected to the p-type material (cathode) and the negative terminal to the N-type material (Anode), a large current will flow.

This is called forward current or forward biased.

If the connections are reversed, a very little current will flow. This is because under this condition, the p-type material will accept the electrons from the negative terminal of the battery and the N-type material will give up its free electrons to the battery, resulting in the state of electrical equilibrium since the N-type material has no more electrons. Thus there will be a small current to flow and the diode is called Reverse biased.

Thus the Diode allows direct current to pass only in one direction while blocking it in the other direction. Power diodes are used in concerting AC into DC. In this, current will flow freely during the first half cycle (forward biased) and practically not at all

during the other half cycle (reverse biased). This makes the diode an effective rectifier, which convert ac into pulsating dc. Signal diodes are used in radio circuits for detection. Zener diodes are used in the circuit to control the voltage.

Manufacturing Considerations

Manufacture of the Power-Generating Shock Absorber will require a machined main shaft with embedded permanent magnet stack, a strong air-gap cylinder housing, high quality stator windings, and robust slide bearings. Other systems, such as microprocessor-controlled voltage, current, and dampening regulation, external casing, protective bellows, etc. will also need to be designed and tested.

Applications

LMES technology is already finding its place in ocean power generating systems. Its introduction into the automotive world is the next logical step. This technology can be applied to any type of vehicle that employs movable suspension technology and uses electricity in some form as its fuel.

Hard ware :_

Diode Capacitor Resistor Transistor Dc motor Solar panel Dynamo Dc battery Pcb Wire Solder wire