Optical Fiber & Electrical Fundamental Rights

        Mechanical Pump: The mechanically operated diaphragm type fuel pump is operated by an eccentric mounted on the camshaft of the engine. The pump consists of a spring loaded flexible diaphragm actuated by a rocker arm. The rocker arm is actuated by the eccentric. Spring loaded valves are there in the inlet and outlet of the pump. These valves ensure flow of fuel in the proper direction.         As the rocker arm is moved by the eccentric, the diaphragm is pulled down against the spring force. This movement causes a partial vacuum in the pump chamber. Now the delivery valve remains closed and the suction valve opens. This admits fuel into the pump chamber. At the maximum position of the eccentric, the diaphragm is flexed to the maximum extent after this further rotation of the eccentric will release the rocker arm. Now the rocker arm will simply follow eccentric by the action of the retur...

Introduction : The fuel system of an Internal Combustion engine is intended to produce a combustibl  mixture composed of the fuel stored in the fuel tank and the atmospheric air, and then deliver both to the cylinders. Petrol engines use light grade gasoline. Components of fuel feed system:   The fuel feed system of a petrol engine are having the following components. 1. Fuel Tank 2. Fuel Pump 3. Fuel Filter 4. Carburetor 5. Intake manifold 6. Fuel lines 7. Fuel Gauge Oil Bath Type Air Cleaner Dry Type Air Cleaner Centrifugal Type air cleaner OIL BATH TYPE AIR CLEANER Types of Fuel Feed Systems: The fuel from the fuel tank can be supplied to the  engine cylinder by the following systems. 1. Gravity System.  2. Pressure system  3. Vacuum System 4. Pump System  5. Fuel Injection System. Functions of fuel feed system: 1. To store the fuel in the fuel tank. 2. To supply fuel to the engine to the required amount and in proper  condition...

The valves used in four stroke engines are operated by two mechanisms. 1. valve mechanism for operating the valve in engine block or straight or side valve mechanism. 2. Valve mechanism for operating the valve in cylinder head or over head valve mechanism. Side valve operating mechanism      This mechanism is used in the engine block. It is mostly adopted in L,T and F type engine heads. The valve stem slides up and down in the valve stem guide which acts as a slipper bearing. It also prevents the gases from passing from the valve port to the valve chamber of the engine block. Valve spring is fitted between the engine block and spring retainer, which keeps the valve closed tightly on the valve seat, until lifted by the valve tappet by the rotation of the cam. The tappet or lifter is held between guide which is generally a part of the engine block. Adjusting screw is provided on the tappet to adjust the clearance between the uppe...

              The four stroke engine comprises of suction, compression, power or  working and exhaust strokes. 1. Suction Stroke: When the piston moves from TDC to BDC the inlet valve  opens and due to the downward movement of piston a partial vacuum is created in the cylinder above the piston. Due to this partial vacuum air is sucked in at the end of stroke the inlet valve closes. 2. Compression Stroke: When the piston starts moving from BDC to TDC  the air which has been trapped in the cylinder starts getting compressed, when the piston reaches near TDC, the trapped air gets so compressed that its temperature reaches between 5000C to 6500C. this higher increase in temperature is because of higher compression ratio, in this stroke both valves remain closed. 3. Power Stroke: At the end of compression stroke diesel oil is sprayed in  fine atomized form to the burning hot air which has attained te...

The classification of petrol engines on the arrangement of cylinder is as follows. 1. Inline arrangement – 2 in line, 3 inline, 4 inline, 6 inline and 8 inline. 2. V arrangement – v-4, v-6, v-8 and v-12. 3. Opposed cylinder or flat arrangement – flat 2, flat 4 and flat 6. 4. Radial cylinder arrangement. Construction and working of 2 Stroke and 4 stroke engines  Two Stroke engine:                     The two stroke engine there are two strokes namely upward stroke and downward stroke. In a two stroke engine, the two strokes are completed in two strokes of the piston or one complete revolution of the crankshaft. Upward stroke: during the upward stroke the piston moves upward from bottom dead centre to top dead centre. The air fuel mixture or air is compressed in the combustion chamber of the cylinder. Due to upward movement of the piston, a partial vacuum is created in the crankcase, and a new c...

Materials used, function and Constructional details of Petrol Engine Components Engine consists of the following parts. 1. Cylinder block  2. Cylinder head 3. Crankcase  4. Piston 5. Piston Rings  6. Piston Pin 7. Connecting Rod  8. Crankshaft 9. Flywheel  10. Valves and valve mechanism 11. Rocker Arm  12. Camshaft besides the above components engine contain so many accessories like aircleaner,  oil filter, automatic chokes, automatic heat controls, spark plug, ignition devices, carburetors, manifolds, vibration damper etc. Materials used for various components:  The cylinder block and cylinder heat are made of gray cast iron and sometimes with addition of nickel and chromium. Some cylinder blocks are  cast from aluminum, cast iron or steel. The cylinder blocks are made of casting process. Small engine cylinder blocks walls are plated with chromium to reduce wall wear and to increase their service life. The cylinder gasket...

Materials used, function and Constructional details of Petrol Engine Components Engine consists of the following parts. 1. Cylinder block 2. Cylinder head 3. Crankcase 4. Piston 5. Piston Rings 6. Piston Pin 7. Connecting Rod 8. Crankshaft 9. Flywheel 10. Valves and valve mechanism 11. Rocker Arm 12. Camshaft besides the above components engine contain so many accessories like aircleaner,  oil filter, automatic chokes, automatic heat controls, spark plug, ignition devices, carburetors, manifolds, vibration damper etc. Materials used for various components: The cylinder block and cylinder heat are made of gray cast iron and  sometimes with addition of nickel and chromium. Some cylinder blocks are cast from aluminum, cast iron or steel. The cylinder blocks are made of casting process. Small engine cylinder blocks walls are plated with chromium  to reduce wall wear and to increase their service life. The cylinder gaskets are made of copper-asbestos, steel asbe...

The I.C. Engine can be classified on the basis of 1. Working cycle: a. Otto cycle Engine or Spark Ignition Engine (S.I.Engine) b. Diesel Cycle Engine or Compression Ignition engine (C.I. Engine) 2. Number of strokes: a. Two Stroke engine b. Four Stroke engine. 3. Fuel used: a. Liquefied petrol engines b. Diesel engines c. Gasoline or petrol d. Compressed Natural gas engines, e. Methane or ethanol engines. 4. Fuel supply system: a. Fuel supply through carburetor b. Fuel injected by Fuel injecting pump. 5. Method of ignition: a. battery or coil ignition b. Magneto ignition c. Electronic ignition 6. Method of cooling: i) Air cooled ii) Water cooled 7. Cylinder Arrangement: i) in line type ii)V type iii) Opposed cylinder type iv)Radial type 8. Valve operating system: i) Overhead type ii) Side valve type

Types of engines: Mainly engines are of two types. External Combustion Engines (E.C. Engines) E.g.: Steam Engines. Internal Combustion Engines (I.C. Engines) E.g.: All Automobile Engines. External Combustion Engines: The External Combustion Engines are  those in which the combustion takes place outside the engine cylinder. E.g.: Steam Engine. Internal Combustion Engines: In the Internal Combustion Engines the  combustion of fuel takes place inside the engine cylinder. E.g.: All Automobile Engines.        Functions of I.C. Engine: Engine is that kind of prime mover which converts chemical energy of fuel into mechanical energy. The fuel on burning changes to gas which impinges upon the piston and pushes it to change into reciprocating motion. The reciprocating motion of piston is then converted to rotary motion of crank shaft with the help of slider mechanism involving connecting rod and crank shaft. Several types of I....

Introduction: An automobile is a self propelled vehicle which is used for the transportation of passengers and goods upon the ground. Auto means automatically and mobile or motive means one which can move. Automobile engineering is a branch of mechanical engineering and have practice to propel them. Car, bus, truck, jeep, tractor, scooter, motorcycle are examples of automobiles. ENGINE: It is a machine which converts heat energy into mechanical energy. It should be understandable that the energy supplied to the engine is of the chemical form like diesel or petrol or kerosene. This chemical energy is converted into heat energy by the process of compression or spark ignition inside the engine. The heat energy is then is converted into mechanical energy.

                             Proper cleaning of connectors is very important. The core diameter of a single-mode fiber is only about 9um. This generally means you cannot see streaks or scratches on the surface. Follow the under mentioned procedure to clean the connector. 1 Clean the connector by rubbing it on cleaning tape or a new, dry cotton swab using a small circular movement. 2. Blow away any remaining lint with compressed air. If the connector has greasy dirt on its tip follow the following procedure. 1. Take a new Moisten cotton swab with isopropyl alcohol. 2. Clean the connector by rubbing the cotton swab over the surface using a small circular      movement. 3. Take cleaning tape and rub it in small circular motion to remove the alcohol dissolved       sediment and dust. 4. 4. Blow away any remaining lint with compressed air.

                 Losses occur at many points in a fibre optic system. We have to ensure that the light source launches enough power into the fibre to provide enough power at the receiver. The receiver has limited sensitivity. Transmitter output - Receiver input = Losses + Margin (All calculations are done in dB)         Types of Loss For single mode fiber cable with two most commonly used wavelengths— 1310 nm and 1550 nm—The attenuation measurement will vary depending upon which wavelength is in use. Attenuation is measured in dB and is quoted as attenuation in dB/km.          Fiber Loss Variables • Attenuation: All fiber has losses from absorption and back reflection of the light caused by impurities in the glass. Attenuation is a function of wavelength and needs to be specified or measured at the wavelength in use. • Modal Dispersion: The higher the data rate, the shorter the di...

              There is a difference between the power coupled into a component like a cable or a connector and the power that is transmitted through it. This difference is what we call optical loss and defines the performance of a cable, connector, splice, etc. • Measuring power Power in a fibre optic system is like voltage in an electrical circuit. To measure power, attach the meter to the cable that has the output you want to measure. Turn on the transmitter/source and note the power the meter measures. • Testing Loss Following two methods are used to measure loss. Optical Loss Test Sets houses a light source and power meter in the same unit. For both methods two units of loss test sets (one at each end of the fibre under test) are required. • Single Ended Loss (Laser Source and Power Meter) This test is initiated from one end and result is displayed at far end unit. • Double Ended Loss (FasTest Method) In this test Laser source is ...

        Cables need to be tested for Continuity, End-to-End Loss and any other potential problems. For long outside plant cables with intermediate splices, all individual splices need to be verified with an OTDR, since that's the only way to make sure that each one is good. Within the network testing for power is necessary as power is the measurement that tells whether the system is operating properly. Tools and Test Equipment for the job. 1. Source and power meter, optical loss test. 2. Reference test cables 3. Cleaning materials - lint free cleaning wipes and pure alcohol. 4. OTDR and launch cable for outside plant jobs.

1. Stripping of fibers Once the coated fibre is exposed, Use fiber stripper to strip fibre to appropriate length. Take care not to damage the fibres in the process. 2. Cleaning After the coating is removed, clean the fibre with specially designed isopropyl alcohol wipes so that the fibre squeaks. 3. Cleaving A good cleave is the key to obtaining a good splice. Use cleaver to cut the fibre. After cleaving do not touch or clean the fibre. 4. Splicing The fibre is now ready to be spliced mechanically or Fusion. Insert the fibre carefully in the mechanical splice or in the fusion splicer for splicing. Whileinserting in the mechanical splice make sure that fibre is inserted directly in the groove and do not touch any other surface. Fusion splicer will automatically align and fuse the fibre. 5. Protection. In case of fusion splicing cover the splice with heat shrink sleeve and place it in the heater, for mechanical splice carefully close the mechanical splice. 6. Organi...

1. Removal of outer jacket Remove the fibre optic cable's protective jackets and buffers to allow access to the optical fibre. Make sure the blades or cutting members are not damaging the buffer tubes. 2. Cutting of Kevlar. The Kevlar can be trimmed using scissors or Kevlar cutters. 3. Cleaning of Buffer Tubes. Clean the jelly on buffer tubes with isopropyl wipes. 4. Fixing of cable in the enclosure. The cable should be fixed in the enclosure according to the recommendations of the manufacturer of the splice enclosure. 5. Stripping of Buffer Tubes. The buffer tubes, like the outer jackets, can be removed by mechanical stripping tools. Use care not to kink or damage the internal coated fibres.

         There are two methods of fibre optic splicing, fusion splicing & mechanical splicing. Mechanical splicing is usually carried out for emergency restorations whereas fusion splicing is done for permanent repairs of damaged cable or to connect the reels of cable during installation Mechanical Splicing: Mechanical splices are simply alignment devices, designed to hold the two fibre ends in a precisely aligned position thus enabling light to pass from one fibre into the other. (Typical loss: 0.3 dB) Fusion Splicing: Fusion splicing is the joining and fusing of two fibres by placing them between two electrodes, and discharging an electric arc over the fibres. This splice technique is non-reflective. Fusion splicing machine is used to precisely align the two fibre ends then the glass ends are "fused" together using electric arc. This produces a continuous connection between the fibres enabling lower loss and less back reflection than mechanical s...

• Optical Power Meter: An instrument that measures optical power from the end of a fibre • Laser Source: An instrument that uses a laser or LED to send an optical signal into fibre for testing loss of the fibre • Optical Loss Test Set (OLTS): A measurement instrument for optical loss that includes both a power meter and laser source • Reference Test Cables: Short, single fibre cables with connectors on both ends, used to test unknown cables. • Mating Adapter: Also called couplers, allow two cables with connectors to mate. • Optical Microscope: Used to inspect the end surface of a connector for dirt.

• Attenuation: The reduction in optical power as it passes along a fibre, usually expressed in decibels (dB). • Bandwidth: The range of signal frequencies or bit rate within which a fibre optic link or network will operate. • Chromatic dispersion: A property of optical fibre due to which different wavelengths travel at different speeds and arrive at different times, resulting in spreading of a pulse in an optical waveguide. • Decibels (dB): A unit of measurement for optical power which indicates relative power. A -10 dB means a reduction in power by 10 times. • dBm: Absolute Power, Optical power referenced to 1 milliwatt. • Nanometer (nm): A unit of measure used to measure the wavelength of light (meaning one one-billilonth of a meter) • Optical Loss: The amount of optical power lost during transmission of through fiber, splices, couplers, etc. expressed in dB. • Optical Power: It is measured in "dBm", or decibels referenced to one miliwatt of...

• Splice enclosures For long cable runs outside, the point where cables are spliced, sealed up and buried in the ground, put in a vault of some kind or hung off a pole. • Splice panels Connect individual fibres from cables to pigtails • Splice: A permanent joint between two fibres • Mechanical Splice: A splice where the fibres are aligned by mechanical means • Fusion Splice: A splice created by fusing two fibres together • Fusion Splicer: An instrument that splices fibres by fusing them, typically by electrical arc.

1. Terminations • Patch panels:-   Provides a centralized location for patching fibres, testing, monitoring and restoring cables. • Connector:    A non-permanent device for connecting two fibres or fibres to equipment where they are expected to be disconnected occasionally for testing or rerouting. It also provides protection to both fibres. • Ferrule:   A tube which holds a fibre for alignment, usually part of a connector • LC Connector LC stands for Latched Connector and its interconnect is based upon the RJ-45 telephone interface. The LC Connector uses Zirconia ceramic ferrules in a free-floating and pull proof design. • SC connector SC Stands for Single Coupling. It is Square shaped snap-in connector that latches with a simple push-pull. The SC connector has the advantage (over ST) of being duplexed into a single connector clip with both transmit/receive fibres. • MU Connector The MU stands for Miniature Unit fibre-optic connector, which...

1. Core: The centre of the fibre through which the light is transmitted. 2. Cladding: The outside optical layer of the fibre that traps the light in the core and guides it along and even through curves. 3. Buffer coating or primary coating: A hard plastic coating on the outside of the fibre that protects the glass from moisture or physical damage.         Fiber optic cable functions as a "light guide," guiding the light introduced at one end of the cable through to the other end. The core and cladding are manufactured together as a single piece of silica glass. The core region’s refractive index (or optical density) is greater than the cladding layer. The glass does not have a hole in the core, but is completely solid throughout. The light is "guided" down through the core. The cladding traps the light in the core using an optical technique called "total internal reflection.” The third section of an optical fibre is the outer protective coatin...

               Fibre Optic is a thin strand of highly transparent glass or sometimes plastic that guide light. It is used as a medium for carrying information from one point to another in the form of light. A basic fibre optic system consists of a transmitting device, which generates the light signal; an optical fibre cable, which carries the light; and a receiver, which accepts the light signal transmitted. The fibre itself is passive and does not contain any active properties

Three basic types of fiber optic cable are used in communication systems: 1. Step-index multimode 2, Step-index single mode   3, Graded-index Step-index multimode fiber has an index of refraction profile that “steps” from low to high to  low as measured from cladding to core to cladding. Relatively large core diameter and  numerical aperture characterize this fiber. The core/cladding diameter of a typical multimode  fiber used for telecommunication is 62.5/125 μm (about the size of a human hair). The term  “multimode” refers to the fact that multiple modes or paths through the fiber are possible. Stepindex  multimode fiber is used in applications that require high bandwidth (< 1 GHz) over  relatively short distances (< 3 km) such as a local area network or a campus network backbone.       The major benefits of multimode fiber are: (1) it is relatively easy to work with; (2) because of  its larger core ...

           Fiber optics is a medium for carrying information from one point to another in the form of light.  Unlike the copper form of transmission, fiber optics is not electrical in nature. A basic fiber            optic system consists of a transmitting device that converts an electrical signal into a light  signal, an optical fiber cable that carries the light, and a receiver that accepts the light signal and  converts it back into an electrical signal. The complexity of a fiber optic system can range from  very simple (i.e., local area network) to extremely sophisticated and expensive (i.e., longdistance  telephone or cable television trunking). For example, the system shown in Figure could be built very inexpensively using a visible LED, plastic fiber, a silicon photodetector, and some simple electronic circuitry. The overall cost could be less than $20. On the other hand, a typical system used...

Optical fiber systems have many advantages over metallic-based communication systems. These advantages include: • Long-distance signal transmission The low attenuation and superior signal integrity found in optical systems allow much longer intervals of signal transmission than metallic-based systems. While single-line,voice-grade copper systems longer than a couple of kilometers (1.2 miles) require in-line signal for satisfactory performance, it is not unusual for optical systems to go over 100 kilometers (km), or about 62 miles, with no active or passive processing. • Large bandwidth, light weight, and small diameter Today’s applications require an ever-increasing amount of bandwidth. Consequently, it is important to consider the space constraints of many end users. It is commonplace to install new cabling within existing duct systems or conduit. The relatively small diameter and light weight of optical cable make such installations easy and practical, saving valuabl...

Introduction                                     Since its invention in the early 1970s, the use of and demand for optical fiber have grown tremendously. The uses of optical fiber today are quite numerous. With the explosion of information traffic  due  to the Internet, electronic  commerce,  computer  networks,  multimedia, voice, data, and video,  the need for a  transmission medium with the  bandwidth  capabilities for handling  such vast amounts of  information is  paramount. Fiber optics, with  its comparatively  infinite bandwidth, has proven to be the solution.                    Companies such as AT&T, MCI, and U.S. Sprint use optical fiber cable to carry plain old telephone service (POTS) across their nationwide networks. Local telephone service providers...