magnetism

Magnetic phenomena are universal in nature.Magnetism is one aspect of the combined electromagnetic force. It refers to physical phenomena arising from the force caused by magnets, objects that produce fields that attract or repel other objects. ... Permanent magnets, made from materials such as iron, experience the strongest effects, known as ferromagnetism.

 The magnetic field lines

             The pattern of iron filings permits us to plot the magnetic field lines*. This isshown both for the bar-magnet and the current-carrying solenoid. Electric fieldlines of an electric dipole are also  magnetic fieldlines and these lines are a visual and intuitive realisation of the magnetic field. 

Their properties are:

(i)The magnetic field lines of a magnet (or a solenoid) form continuousclosed loops. This is unlike the electric dipole where these field linesbegin from a positive charge and end on the negative charge or escapeto infinity.

(ii)The tangent to the field line at a given point represents the direction ofthe net magnetic field B at that point.

(iii)The larger the number of field lines crossing per unit area, the strongeris the magnitude of the magnetic field B. B is largeraround region  ii  than in region  i  .

(iv)The magnetic field lines do not intersect, for if they did, the direction of the magnetic field would not be unique at the point of intersection.One can plot the magnetic field lines in a variety of ways. One way is to place a small magnetic compass needle at various positions and note its orientation. This gives us an idea of the magnetic field direction atvarious points in space.

PERMANENT MAGNETS AND ELECTROMAGNETS 

Substances which at room temperature retain their ferromagnetic propertyfor a long period of time are called permanent magnets. Permanent magnets can be made in a variety of ways. One can hold aniron rod in the north-south direction and hammer it repeatedly.The method of the illustration is from a 400 year old book to emphasise that the making of permanent magnets is an old art. One can also hold a steel rod and stroke it with one end of a bar magnet a large number of times, always in the same sense to make a permanent magnet.

An efficient way to make a permanent magnet is to place aferromagnetic rod in a solenoid and pass a current. Themagnetic field of the solenoid magnetises the rod.The hysteresis curve allows us to select suitable materials for permanent magnets. The material should have high retentivity so that the magnet is strong and high coercivity so that the magnetisation is not erased by stray magnetic fields,temperature fluctuations or minor mechanical damage.Further, the material should have a high permeability. Steel is one-favoured choice. It has a slightly smaller retentivity thansoft iron but this is outweighed by the much smaller coercivityof soft iron. Other suitable materials for permanent magnetsare alnico, cobalt steel and ticonal.

Ferromagnetism

Ferromagnetic substances are those which gets strongly magnetised whenplaced in an external magnetic field. They have strong tendency to movefrom a region of weak magnetic field to strong magnetic field, i.e., they get strongly attracted to a magnet.

The individual atoms (or ions or molecules) in a ferromagnetic material possess a dipole moment as in a paramagnetic material. However, they interact with one another in such a way that they spontaneously align themselves in a common direction over a macroscopic volume called domain. The explanation of this cooperative effect requires quantum mechanics and is beyond the scope of this textbook. Each domain has a net magnetisation. Typical domain size is 1mm and the domain contains about 1011 atoms. In the first instant, the magnetisation varies randomly from domain to domain and there is no bulk magnetisation. When we apply an external magnetic field B0, the domains orient themselves in the direction of B0 and simultaneously the domainoriented in the direction of B0 grow in size. This existence of domains andtheir motion in B0 are not speculations. One may observe this under amicroscope after sprinkling a liquid suspension of powdered

bio gas

What  is  biogas? 

 Biogas  is  produced  after  organic  materials (plant  and  animal  products)  are  broken  down by  bacteria  in  an  oxygen-free  environment,  a process  called  anaerobic  digestion.  Biogas systems  use  anaerobic  digestion  to  recycle these  organic  materials,  turning  them  into biogas,  which  contains  both  energy  (gas), and  valuable  soil  products  (liquids  and solids).   Anaerobic  digestion  already  occurs  in nature,  landfills,  and  some  livestock  manure management systems,  but  can  be  optimized,  controlled,  and  contained  using  an  anaerobic  digester.  Biogas  contains roughly  50-70  percent  methane,  30-40  percent  carbon  dioxide,  and  trace  amounts  of  other  gases. solid  digested  material, called digestate,  is  frequently  used as  a soil  amendment.

Biogas is a clean, nonpolluting and low contains about 55 to 75 per cent methane, which is inflammable. Biogas can be produced from cattle dung, human waste and other organic matter by a process called "anaerobic digesti  cost fuel. It on" in a biogas plant. The digested material, which comes out of the plant is an inreached manure.

Typical waste streams for Anaerobic Digestion  

• Fruit & Veg waste 

• Restaurant waste 

• Agricultural waste such as livestock manure, silage • Abattoir waste 

• Fat trap/clarifier waste from food industry and           restaurants

• Activated sewage sludge 

• Paper sludge 

Biogas technologies

The development of biogas technologies in Georgia started in 1993-1994 with the assistance of GTZ (Technical Cooperation Agency of Germany). Technical support provided by GTZ allowed Georgian experts and engineers to study advanced designs and adapt technologies to Georgian climatic and economic conditions. 

The process of biogas production takes place in anaerobic conditions and in different temperature diapasons. There are psychrophilic (temperature diapason 10-250C), mesophilic (25-400C) and thermophilic (50-550C) regimes of bioconversion. Biogas production in a thermophilic regime is much higher than for the mesophilic and psychrophilic regimes. Modern thermophilic bioreactors can produce 2-6 m3 per m3 of installation, which amounts to 5-15 kg of waste on a dry mass base (or 50-150 kg of wet mass). For mesophilic biogas installations, these values are 0.2-0.4 m3 per m3 of installation and 0.5-1 kg on a dry mass base (or 5-10 kg of wet mass). Biogas reactors, working in a thermophilic regime, can be introduced in agricultural farms where the number of livestock exceeds 5. Biogas produced on such farms can be used not only for cooking and heating water, but for dairy production as well.

Working

From the above, in the inlet tank animal waste slurry is prepared containing cow dung and waste in the ratio as 1:1 to 1:1.25 the feeding of animal waste slurry is usually done once in a day.
The sludge comes out with the built up of gas pressure in the dome above the partition wall & flows out to the outlet tank the th’ A C outlet pipe. This sludge is an excellent fertilizer which can be again fed to the soil. At the top of the gas holder , the accumulated gas is drawn from the pipe through gas value. The bifurcation of digestion chamber through a partition wall providers optimum conditions for growth of acid formers & methane forms as the PH valve requirement for these bacteria are different. Therefore, this gives a good yield of biogas. It operates naturally under constant pressure. The diameter of the digester of a gas plant rangers from 1.2 to 6m. & its height varies from 3m to 6m.
The mild steel gas holders are prone to corrosion thus needs painting at regular intervals. This problem can be overcome by using fiber glass reinforced plastic (FRP) material for construction of gas holders. However it is constly.

Advantages of Biogas

• It's a Clean & Renewable Energy Source.
• It Reduces Soil & Water Pollution. 
• Prevents Health Problems & Biodiversity Loss. 
• Generates Organic Fertilizer. 
• It's A Simple and Low-Cost Technology That Encourages A Circular Economy. 
• Healthy Cooking Alternative For Developing Areas.

Application of biogas

There are many application of biogas. Given structure of biogas.

Dangers

The air pollution produced by biogas is similar to that of natural gas. The content of toxic hydrogen sulfide presents additional risks and has been responsible for serious accidents.Leaks of unburned methane are an additional risk, because methane is a potent greenhouse gas.
Biogas can be explosive when mixed in the ratio of one part biogas to 8–20 parts air. Special safety precautions have to be taken for entering an empty biogas digester for maintenance work. It is important that a biogas system never has negative pressure as this could cause an explosion. Negative gas pressure can occur if too much gas is removed or leaked; Because of this biogas should not be used at pressures below one column inch of water, measured by a pressure gauge.
Frequent smell checks must be performed on a biogas system. If biogas is smelled anywhere windows and doors should be opened immediately. If there is a fire the gas should be shut off at the gate valve of the biogas system.

insulator

An insulator is a material that does not conduct electrical current. Insulating materials include paper, plastic, rubber, glass and air. Vacuum is also an insulator, but is not actually a material. Most electrical conductors are covered by insulation. Magnet wire is coated with an extremely thin layer of insulation so that more turns or larger wire may be used in the winding of transformers etc. Insulators are generally rated at hundreds of volts, but some that are used in power distribution are rated as high as hundreds of thousands of volts. Insulators support and/or keep electrical conductors from making unintended contact with each other.

 Best material of insulator

 The best insulator in the world right now is most probably aerogel, with silica aerogels having thermal conductivities of less than 0.03 W/m*K in atmosphere. of aerogel preventing ice from melting on a hot plate at 80 degrees Celsius! Aerogel has its amazing properties because it's mostly made out of air.

(1)  pin type insulator

(2). Suspension type insulator

(3). Strains insulator

(4). Shackle insulator

(5). Over head line insulator

(1) Pin Type Insulator

• it consists of a single or multiple units.
• it is secured to the cross-arm on the pole.
• it used only to 33 KV.
• beyond operating voltage of 33 KV, it becomes to bulky and uneconomical.
• there is a groove on the upper end of the insulator for housing the conductor.
• the conductor passes through this groove and is bound by annealed wire of the same material as the conductor.

(2) Suspension Type Insulator

• it used for voltages above 33 KV.
• it consists of a number of disc units mounted one above each other to form a string.
• the conductor is suspended at the bottom end of the string while the other end of the string is secured ti the cross-arm of the tower.
• 
  
• Advantages of Suspension Type Insulator are
• cheaper than pin type for voltages beyond33 KV.
• number of units in the string depend on working voltage as they are connected in series.
• each disc of the string is designed for low voltage 11 KV.
• if any disc is damaged, it can be replaced easily.
• string has a high flexibility.
• additional insulation can be provided by adding the desired number of discs to the string.
• Disadvantages of Suspension Type Insulator are
• costlier than pin type for voltages under 33 KV.
• it requires more height of supporting structure than pin type need which is uneconomical.
• the amplitude of free swing of conductors is larger in suspension type, hence, more spacing between conductors should be provided (by making the arms of the tower more long).

(3) strains insulator

A  strain insulator is an electrical insulator that is designed to work in mechanical tension (strain), to withstand the pull of a suspended electrical wire or cable. They are used in overhead electrical wiring, to support radio antennas and overhead power lines. A strain insulator may be inserted between two lengths of wire to isolate them electrically from each other while maintaining a mechanical connection, or where a wire attaches to a pole or tower, to transmit the pull of the wire to the support while insulating it electrically. Strain insulators were first used in telegraph systems in the mid 19th century.

(4) shackle insulator

Shackle type insulator  is  an insulator  of  generally cylindrical form,  the other  name of  shackle insulator is  butterfly  insulator,  because porcelain shackle type insulator  has  two  or  four  big  sheds  looks  like butterfly,  so we  some place calls  it    butterfly insulator. 

The  application of  shackle insulator 

Shackle insulator  like spool  insulator,  both  of  them have a hole，a  D-iron  bracket  with  bolts  cross  the hole of  shackle insulator.  Shackle insulator’s  main function is  combinations  with D-iron  bracket  fixed on telegraph pole and  insulate the conduct  wire. 

The color of  shackle insulator Shackle  insulator  has  different colors  to  meet different  countries’  demand .

•  Grey 
•  White   
•  Brown   
•  Blue 
•  Green   

(5) overhead line insulator

  An overhead line  may  be  used to  transfer  or  distribute  electric  power.  The  proper overhead line  operation  depends  to a  big  extent  upon  its  mechanical  design.  While constructing  an  overhead line,  it  has  to  be verified  that  line  mechanical  strength is  such so as  to provide  against  the  most  probable  weather  conditions.  Typically,  the main elements  of  an overhead  line  are:   

- - Conductors  which  transfer  power  from  the sending  end station to the receiving end  station.

 Supports  which may  be poles  or  towers.  They  keep  the  conductors  at an appropriate  level  above the  earth. 

- Insulators  that  are  connected  to supports  and  insulate the conductors  from  the earth.

- - Cross arms which  give  support  to  the insulators.

Miscellaneous  elements  such as  phase  plates,  danger  plates,  surge  arrestors, etc.


The overhead  line  operation  continuity  depends  upon  the judicious  selection  of  above elements.  Hence,  it  is  beneficial  to  have detailed discussion on them.


Material of insulator

(a) Polyethylene is a thermoplastic material that combines unusual electrical process, high resistance to moisture and chemical, easy processability and low cost. It has got high resistivity and good dielectric properties at high frequencies and therefore, is widely used for power and coaxial cables, telephone cables multi-conductor control cable, TV lead-in wire etc.

(b) Fibre glass. It is made from material, which is a free alkali metal oxide, which may form a surface coating that may attack the glass silicates. Glass does not absorb moisture volumetrically, but may attract it by capillary action between the fine filaments. Tapes and clothes woven from continuous filament yarns of glass have high resistivity, thermal conductivity and tensile strength and from a good class B insulation. Glass is used as a cover and for internal support in electric bulb, electronic valve, mercury arc switches, X-ray, equipment capacitors and as an insulator in telephone.

(c) Porcelain. It is made from china clay used as insulating supports for overhead lines, and also in making spark plugs. Inferior porcelain is used in low voltage switches and fine gears.

(d) Asbestos. It is a mineral substance, fibrous in structure and is of white or brown colour. It is an incombustible and fire-proof materials good insulator of sound, heat and electricity widely used in steam pipe joints, making fire proof roofing materials, partition wall, Electric Iron and Heating Oven etc.

(e) Bakelite. It is a synthetic product. Insulating properties are good and so is used in making all kinds of small electrical fitting, terminal boards, lamp holders, switch covers etc.

(f) Empire Cloth. It is made by varnishing cotton cloth, silk or paper and is used as wrapper of armature coils.

(g) Mica. It is a mineral product and occurs as crystals. It is easily split into thin sheets and is not much used in pure form, it is fire proof and does not absorb moisture. It is used as an insulating material for Heaters, Irons, Commutator of DC motor etc.

(h) V.I.R. Insulation. It is prepared by mixing with pure rubber about 5% of sulphur, Zinc Oxide, Whiting and some colouring matters. The mixture is then heated to about 150 degree centigrade and in vulcanised form, rubber is made tough which does not absorb moisture. It forms a good insulating and protective covering for low and medium voltage cable conductors.

(i) Ebonite. It is vulcanised rubber containing about 30% to 50% of sulphur which is subjected to prolonged heating at about 150 degrees C. It is a hard substance and can be moulded into different shapes and widely used for making containers of lead acid battery, small Instrument panels and terminal mountings.

(j) Gutta Percha. It is a chemical product whose properties resemble to those of rubber. It is not affected by water even immersed in it. It is suitable insulation for submarine cables.

(k) Bitumen. A natural product, obtained from lakes. Bitumen refined with petroleum compound is used for preparing varnishes and for filling joint boxes of underground cables. Vulcanised bitumen used as an insulating covering for cable conductors, meant especially for damp places.

(l) Press Han. It is a form of paper prepared from hemp, rags, and wood pulp chemically treated. It is widely used for lining in armature slots insulating coil sides for low and medium voltage machines.

(m) Leathered Paper. It is a tough material prepared chemically from cotton rags-which is unaffected by grease and oil and used for slots and coil insulation and also in transformer core covering etc.

(n) Shellac. It is made from the product which grows on some varieties of trees in India. It is used in making insulating varnishes.

(o) Silk & Cotton Cloth. This insulation is used on conductor required for low voltage. The conductor may have a single or double layer covering according to the types of work mostly such wires are used for instrument and armature winding.

(p) Gar Film. It is a good insulator and plastic product used for slots and coil insulation.

(r) Air is a free gift from God. It has got application everywhere in spite of our consent. It is used as insulation in transmission line. It has high insulation resistance but drops due to moisture. When using air, there is very less dielectric loss. At high voltage corona effect takes place. Dielectric strength- 30 KV/cm

GPS SYSTEM

GPS(GLOBAL POSITIONING SYSTEM):-

                                                           GPS or Global Positioning System is a satellite navigation system that furnishes location and time information in all climate conditions to the user. GPS is used for navigation in planes, ships, cars, and trucks also. The system gives critical abilities to military and civilian users around the globe. GPS provides continuous real-time, 3-dimensional positioning, navigation and timing worldwide.

                                              

System Description

GPS has three ‘segments’:

1. The space segment now consists of 32 satellites, each in its own orbit about 11,000 nautical miles above the Earth.
2. The user segment consists of receivers, which you can hold in your hand or mount in your car.
3. The control segment consists of ground stations (five of them, located around the world) that make sure the satellites are working properly.

Application of GPS

GPS is extremely relevant today and used in numerous industries for preparing accurate surveys and maps, taking precise time measurements, tracking position or location, and navigating. Some examples of GPS applications include:

• Emergency Response: When there is an emergency or natural disaster, first responders can use GPS for mapping, following and predicting weather, and keeping track of emergency personnel for safety. In the EU and Russia, the eCall regulation which comes into effect in 2018 relies on GLONASS technology and telematics to send data to emergency services in the case of a vehicle crash, reducing response time. Read more on the benefits of telematics.
• Entertainment: GPS is being used for activities and games like Pokemon Go and Geocaching.
• Health and Fitness: Smartwatches and wearable technology can be used to track your fitness activity (such as miles run,) and benchmark it against others that match your demographics.
• Construction: From locating equipment, to measuring and improving asset allocation, GPS tracking allows companies to increase their return on assets.
• Transportation: Logistics companies are implementing telematics systems to improve driver productivity and safety.

Other industries that use GPS include: agriculture, autonomous vehicles, sales and services, military, mobile communications, security, drones, and fishing.

The Future of GPS

Although GPS has performed extremely well and has generally exceeded expectations, it’s clear some significant improvements are needed. As we continue to investigate the system's needs and deficiencies over the past decade we are better able to determine what capabilities and features should be incorporated into a future GPS to satisfy both military and civil users.

3 Advantages of GPS:

• GPS satellite-based navigation system is an important tool for military, civil and commercial, users
• Vehicle tracking systems GPS-based navigation systems can provide us with turn by turn directions
• Very high speed

GPS symbol

solar cell

Solar cell also known as  photovoltaic.

Solar Cell is an electrical device which converts the light energy into electrical energy. ... This voltage increase whit increase in the light intensity. The cell is so designed that a large area is exposed to light which enhances the voltage generation across the two terminals of the cell.

Introduction  : -

                            Photovoltaic systems behave in an extra ordinary and useful way . They react to light by transforming part of it into electricity . More over this conversion is novel and unique ,since photovoltaics.

• It have no any moving part.
• There is no any container for fluids and gases. 
• It don't need any fuel for operate it.
• It have a rapid response, achieveing all full output instantly.
• It can operate on moderate temperature.
• It didn't produce any pollution when it generate electricity.
• It require a little maintenance if it proper manufacturer and installed .
• It Can be made from silicon. The second most abundant element the earth's crust .
• It Have wide power-handling capabilities, from micro-watts to megawatts.

Clearly, photovoltaics have an appealing range

Of charactorstics.

There is some truth to both of these views. The sun's energy, for all is certainly in-exhaustible. However, even thoughs the Sim light stricking the earth is aboundant, it come in a rather delute form.

Solar cell technology :-

                                Photovoltaics is  the field of  technology  and research related to  the devices which directly convert sunlight into  electricity.  The solar cell  is  the elementary building block of  the photovoltaic technology. Solar cells are  made  of  semiconductor  materials,  such  as  silicon.  One of  the properties of  semiconductors  that makes them most  useful is that their conductivity  may easily be  modified by  introducing impurities into  their crystal lattice.

For instance, in  the fabrication of  a  photovoltaic solar cell, silicon,  which has four  valence electrons, is  treated to  increase  its conductivity. On  one side  of  the cell, the impurities, which are phosphorus  atoms with five  valence electrons (n-donor),  donate  weakly bound valence electrons to  the silicon material, creating excess  negative  charge  carriers. On  the other side, atoms of  boron with three valence electrons (p-donor) create  a  greater affinity  than silicon to  attract electrons. Because the p-type  silicon is in  intimate  contact with the n-type  silicon a  p-n junction is  established and a  diffusion of  electrons occurs from the region of  high electron concentration (the n-type  side) into  the region of  low electron concentration (p-type side).  When the electrons diffuse across  the p-n  junction, they recombine with holes on the p-type  side. However, the diffusion of  carriers does not occur  indefinitely, because the imbalance of charge  immediately on either sides of  the junction originates an electric field.  This electric field forms a  diode that  promotes  current  to  flow  in  only  one  direction. Ohmic metal-semiconductor contacts  are made  to  both the n-type  and p-type  sides of  the solar cell, and the electrodes are ready to  be  connected to  an external load.

When photons of  light fall on the cell, they transfer their energy  to  the charge  carriers. The electric field across  the junction separates photo-generated positive charge  carriers  (holes) from their negative  counterpart (electrons).  In this  way an  electrical  current  is  extracted once  the circuit is  closed on an external load.

Application of solar energy or photovoltaics :-

(1)  Rural electrification

• Temporary housing
• Permanent housing
• Centralised electrification with individual consumption control per house, in rural areas
• Refuge and mountain lodge electrification
• Aid stations. (lighting, medication and vaccine preservation with refrigerators)
• Schools and community centres
• Police stations and borders
• Religious facilities (chapels, missions, etc.)

Rural electrification currently has all of the commodities that a conventional electrification system can have since the incorporation of new sine wave inverters, allowing for the use of any appliance.

One of the most important applications is currently the electrification of small rural areas with centralised systems. The advantages with respect to one installation per house are the following:

• Lower installation cost
• Lower maintenance costs
• Higher level of user friendliness
• Higher security of the facility
• Greater total return

(2) Agricultural applications

• Water pumps both in DC and AC (with battery)
• Direct drive water pumps (without battery)
• Warehouse electrification
• Risk controls
• Greenhouses (automation of windows and lighting)

(3)Lighting:

• Billboards
• Public streetlights
• Bus stops
• Tunnel, cave, etc. lighting

Public lighting, through photovoltaic systems, is presented as one of the most economic solutions to light the entrances of the towns, road junctions, rest areas, etc.
A new type of street light is currently being installed, which does not require any maintenance, by integrating long life stationary batteries with gelled electrolytes (over 300 streetlights in the Canary Islands).
Signage:

• Lighthouses and marine buoys
• Air beacons and radio beacons
• Road signs to indicate curves, obstacles, roundabouts, etc. in cities and on roadways using LEDs
• Time and temperature indicators on public roads
• Railway crossings
• Oil rigs

Advantages

• Electricity produced by solar cells is clean and silent. Because they do not use fuel other than sunshine, PV systems do not release any harmful air or water pollution into the environment, deplete natural resources, or endanger animal or human health.
• Photovoltaic systems are quiet and visually unobtrusive.
• Small-scale solar plants can take advantage of unused space on rooftops of existing buildings.
• PV cells were originally developed for use in space, where repair is extremely expensive, if not impossible. PV still powers nearly every satellite circling the earth because it operates reliably for long periods of time with virtually no maintenance.
• Solar energy is a locally available renewable resource. It does not need to be imported from other regions of the country or across the world. This reduces environmental impacts associated with transportation and also reduces our dependence on imported oil. And, unlike fuels that are mined and harvested, when we use solar energy to produce electricity we do not deplete or alter the resource.
• A PV system can be constructed to any size based on energy requirements. Furthermore, the owner of a PV system can enlarge or move it if his or her energy needs change. For instance, homeowners can add modules every few years as their energy usage and financial resources grow. Ranchers can use mobile trailer-mounted pumping systems to water cattle as the cattle are rotated to different fields.

SOLAR CELL SYMBOL

Why should we go solar?

(1)Save Money

Often times the initial solar power cost of installation seems to eclipse the benefits of a clean, renewable energy source and deters people from pursuing the switch. But what many people don’t realize is that installing solar panels for homes on your roof doesn’t just earn you a badge of environmentalism. It saves money and creates a passive income for the future. Figure out the cost of your monthly electricity bills, and depending on how many panels you plan to install, cut that number in half or even eliminate that responsibility from your budget entirely. Solar panels will immediately lower your electric billand shield you from fluctuating rates and the monotony of dealing with local utility companies. And let’s face it, no one enjoys paying those guys..

(2) Earn Money

While the idea of saving money on your electricity bill may already be enough to entice you to jump aboard the solar power bandwagon, many people forget the possibilities of actually profiting from the switch. Renewable energy incentives such as rebates, tax credits, and other various incentives are often offered through your state. If you find you are eligible for these incentives after solar panel installation, the local utility company may be required to pay YOU (through cash or credit) for energy produced and supplied by your panels. Which is pretty great.

(3)Increase Your Property Value

Increasing your property value is always a plus. Not only does solar power save you money and can create added income, purchasing solar panels can actually raise your property value. If you are considering a home remodel to sell in the future, the incentives and credits will help to ease the cost while the panels themselves retain its value, fetching approximately five percent more when your home is finally placed on the market. All aspects considered, solar panels are a remarkable investment for your future as well as the environment.

(4) Help Our Planet

By switching to residential solar energy you are helping the transition to from an over-consumption of fossil fuels to a clean, renewable energy source that will neither deplete nor damage our water, soil, and air. Sustainable energy is the future of power and attainable in the present. To effectively reduce greenhouse gas emissions and begin to neutralize cataclysmic climate change, personal steps must first be taken by individuals such as yourself.

Electrical Earthing

Earthing:

Earthing can simply be defined as the process of protecting against unwarranted spikes and bouts of electricity that can cause damage to life and property. Therefore it is important to remember these key differences between the two. One needs to understand that they both are referring to the same process. A deeper understanding of electric potential can prove useful in this method.

Grounding:

Grounding is similar to Earthing, by which insulation against accidental currents is achieved. The main live wire is connected to a power supply to power an appliance, however, the other portion of the wire is led under the earth. This is done in case of an accidental cut in the circuit, to avoid overloading and other dangerous side effects.

The key difference between earthing and grounding is that the term “Earthing” means that the circuit is physically connected to the ground which is Zero Volt Potential to the Ground (Earth). Whereas in “Grounding” the circuit is not physically connected to ground, but its potential is zero with respect to other points.

Difference between Earthing and Grounding

          Earthing.                                 Grounding

This method protects the human being from electrocuted.	This method protects the entire power system from malfunctioning.
Earthing contains zero potential.	Grounding does not possess any zero potential.
The earth wire used is green in colour.	The wire used for grounding is black in colour
Earthing is primarily used to avoid shocking the humans.	Grounding is primarily used for unbalancing when the electric system overloads.
Earthing is located under the earth pit, between the equipment body underground.	It is located between the neutral of the equipment being used and the ground

Why is an Earthing Necessary?

Earthing is an important component of electrical systems because of the following reasons:

• It keeps people safe by preventing electric shocks
• It prevents damage to electrical appliances and devices by preventing excessive current from running through the circuit
• It prevents the risk of fire that could otherwise be caused by current leakage

Earthing is an important component of electrical systems because of the following reasons:

 It keeps people safe by preventing electric shocks. 

It prevents damage to electrical appliances and devices by preventing excessive current from running through the circuit.

Mostly, the galvanised iron is used for the earthing. The earthing provides the simple path to the leakage current. The shortcircuit current of the equipment passes to the earth which has zero potential. Thus, protects the system and equipment from damage.

Advantages of earthing

From a technical perspective, earthing has some excellent advantages, resulting it in becoming a mainstream practice in the electrical industry.

•  The electrical system is related to the potential of the general earth mass and cannot reach a different potential. The potential of the earth is zero volts and is known as the neutral of the electricity supply. This helps in keeping the balance.
•  Another advantage is that metal can be used in electrical installations without having to worry about conductivity. Though metal is a good conductor of electricity, proper earthing ensures that metal parts not meant to be used for current transfer can be included in the system. This is done by providing a separate path for this faulty current, enabling its immediate detection and stoppage.
•  In cases of surges in the voltage, high voltages can pass through the electricity circuit. These kinds of overload can lead to damaging of devices and danger to human life. When earthing is installed with the electrical installations, the current is routed through a different path and does not affect the electrical system.
•  An electrical circuit has to be connected together with a lot of attention to the kind of reactions each transformer may have in response to any action on the part of any other transformer. The earth is an ever-present conductive surface and helps configure these relationships between different electrical sources and makes them easier to handle.

Connection of the neutral to earth 

The neutral conductor must be earthed at the substation and at other locations as necessary to ensure that the total impedance between neutral and earth does not exceed 10 ohms. In determining the impedance between the neutral and earth all connections of the neutral to earth should be taken into account, including: •  The earth connection at the substation •  The earth connections on the distribution system •  The earth connection at the consumer’s installation.

                      EARTHING SYMBOL

Resistance-earthed neutral (India)Edit

A resistance earth system is used for mining in India as per Central Electricity Authority Regulations. Instead of a solid connection of neutral to earth, a neutral grounding resistor is used to limit the current to ground to less than 750 mA. Due to the fault current restriction it is safer for gassy mines. Since the earth leakage is restricted, leakage protection devices can be set to less than 750 mA . By comparison, in a solidly earthed system, earth fault current can be as much as the available short-circuit current.

The neutral earthing resistor is monitored to detect an interrupted ground connection and to shut off power if a fault is detected.

MINIATURE CIRCUIT BRACKER

Introduction

A MCB is a mechanical switching device which is capable of making, carrying and breaking currents under normal circuit conditions and also making, carrying for a specified time and automatically breaking currents under specified abnormal circuit conditions such as those of short circuit. In short, MCB is a device for overload and short circuitprotection. They are 

used in residential & commercial areas. Just like we spend time to make a thorough check before buying appliances like washing machines or 

refrigerators, we must also research mcbs

MCB COMPONENT

Actuator lever - used to manually trip and reset the circuit breaker. Also indicates the status of the circuit breaker (On or Off/tripped). Most breakers are designed so they can still trip even if the lever is held or locked in the "on" position. This is sometimes referred to as "free trip" or "positive trip" operation.

1. Actuator mechanism - forces the contacts
    Together or apart.
2. Contacts - Allow current when touching and         break the current when moved apart.
3. Terminals
4. Bimetallic strip. .
5. Calibration screw - allows the
     manufacturer to precisely adjust the trip
     Current of the device after assembly
6. Solenoid
7. Arc divider/extinguishe

Working Principle

While the main purpose of this article is about selection of MCBs, it is worth summarizing the working principle of MCBs in brief.

MCB is a compact cased device that has an electro-mechanical mechanism inside that provides overload protection.

There are essentially three different mechanisms inside that provide overload protection:

Bimetallic Strip: This arrangement is used in situations where a constant overload condition prevails over a long time in the connected circuit thus resulting in heating of bimetallic strip. Due to this the bimetallic strip deflects and causes the attached latch to be released. This causes the attached spring to get released and moving contactor open the circuit.

Magnetic Trip Coil: This mechanism comes in force in case of a short circuit event. A short circuit event is associated with a sudden surge of a heavy short circuit current that tends to flow through the circuit. This sudden surge of short circuit current flows through a very sensitive magnetic trip coil inside MCB. This causes a sudden change in magnetic flux and activates the trip coil unit. Due to this, the plunger inside the coil deflects and releases the same latch point and subsequently the same release of spring and opening of the contactor and the circuit.

Manual Switching: MCB also has an external ON/OFF switching option to manually break the circuit. This is used in cases of any maintenance / repair activities or for resetting of MCB and power in case of an already occured trip event.

Technical Specifications –

Selecting a Suitable MCB 

From the technical specifications of an MCB it is possible to deduce which – if any – circuit 

breaker types are basically suitable for the planned protection and switching task.

1. Terminal Block (Cable/Busbar)

Depending on the MCB model, various types of cables/lines (single/multi-core, 

with/without core end sleeve) can be connected in combination with busbars.

2. MCB Type Label

Contains:

Manufacturer brand name       - Siemens

MCB Order No.                            - 5SL6116-7

Indication of tripping
 characteristic/rated current  -    C 16                                

Usability in an electric
 supply network:-                        - 230/400 V AC

3. Quality Label Approval VDE

The product has been tested by an independent testing body and the quality label has been 

approved. (Additional assurance for the end user.)

4. Switching Capacity of the Device in Ampere/Energy Limitation Class

The MCB shown has a switching capacity of Icn 6 kA, and satisfies the requirements of 

Energy Limitation Class 3.

In accordance with the Technical Connection Requirements (TAB) for German network 

operators, only MCBs with a rated switching capacity of min. 6 kA and energy limitation 

class 3 are permitted for use in residential constructions.

5. Handle for Manual Actuation of the MCB

With integrated switch position indicator (I-ON/0-OFF):

• red identification for switch position ON

• green identification for switch position OFF

The main contact position may deviate from the handle position.

Main contacts may e.g. be in OFF position, although the handle is in ON position (trip-free). 

Some MCBs have an additional mechanical display for the actual position of the main contacts.

6. Switching Symbol

Identification for easy recognition of the correct terminal type.

Shown here MCB terminals in single-pole version

The N conductor terminal is identified with the symbol ‘N’.

In multi-pole devices, a horizontal dashed line over the switching contact symbols identifies 

the mechanical coupling of the switching poles.

7. Coupling Location for System Components

The coupling location for additional system components on the MCB ensures indirect trip-

ping of the MCB by forwarding the triggering command to the MCB contact system or by 

transmitting the tripping information to the system component(s).

8. Manual Slide Operation for Quick Fitting System

Easy manual actuation of the MCB for toolless removal from the standard mounting rail.

        Symbol of MCBs

multimeter

What is a digital multimeter?

A digital multimeter is a test tool used to measure two or more electrical values—principally voltage (volts), current (amps) and resistance (ohms). It is a standard diagnostic tool for technicians in the electrical/electronic industries.

Digital multimeters long ago replaced needle-based analog meters due to their ability to measure with greater accuracy, reliability and increased impedance. Fluke introduced its first digital multimeter in 1977.

To better  understand  digital  multimeters,  it’s  helpful  to  become  clear  on  the  basics  of electricity. 

                     After  all,  digital multimeter  always  measure  some  aspect  of  electricity. In  the  case  of electricity,  that  force  might  be  a  generator,  battery,  solar  panel  or  some  other  power supply.  The  pressure  created  by  that  power  supply  is  called  voltage.   Voltage  is  the  pressure  applied  to  the  circuit.   Current  is  the  Flow  of  the  electricity  in  the  conductor.   Resistance  is  any  restriction  to  the  flow  of  the  current  in  a  conductor. Voltage,  current  and  resistance  are  the  three  most  fundamental  components  of  electricity. Voltage  is  measured  in  volts,  current  in  amps  and  resistance  in  ohms. 

What is difference between analog and digital multimeter?

The primary difference between the two is the display, an analog multimeter uses a needle to show the value, while a digital multimeter will show the results as numbers on a screen.

The advantages of using an analog multimeter is when checking a diode the analog is usually more accurate.

The  most  important  debugging  tool  in  any  E.E.'s  toolbox  is  a  trusty  multimeter.  A  multimeter  can  measure  continuity, resistance,  voltage  and  sometimes  even  current,  capacitance,  temperature,  etc.  It's  a  swiss  army  knife  for  geeks!

What can we measure by multimeter?

(1) Continuity

What  is  Continuity? 

                             

You  might  be  asking,  "What  is  continuity?"  But  don't  worry,  it's  quite  simple!  Continuity  means,  are  two  things electrically  connected.  So  if  two  electronic  parts  are  connected  with  a  wire,  they  are  continuous.  If  they  are  connected with  cotton  string,  they  are  not:  while  they  are  connected,  the  cotton  string  is  not  conductive.

You  can  always  use  a  resistance-tester  (ohmmeter)  to  figure  out  if  something  is  connected  because  the  resistance  of wires  is  very  small,  less  than  100  ohms,  usually.  However,  continuity  testers  usually  have  a  piezo  buzzer  which  beeps. This  makes  them  very  useful  when  you  want  to  poke  at  a  circuit  and  need  to  focus  on  where  the  probes  are  instead  of staring  at  the  meter  display.

(2) Resistance

                 Resistance  is  just  what  it  sounds  like,  its  the  characteristic  that  makes  a  component  fight  current  flow.  The  bigger  the resistance  value  (in  ohms  Ω)  the  more  it  fights.  Most resistors  (https://adafru.it/aIo)  you'll  see  range  between  1  ohm  and 1  megaohm  (1.0  MΩ)  they  often  have  5%  tolerance  but  you  can  buy  1%  or  even  0.1%  accuracy  resistors. In  general,  resistence  testing  is  best  for  measuring  resistors,  but  you  may  find  yourself  measuring  the  resistance  of other  things,  such  as  sensors  and  speakers.

What  is  resistance  testing  good  for?

     Resistance-testing  is  very  useful

 If  you  don't  have  a  continuity  tester,  

it  can  double  as  one Check  resistors  whose  values  are  not  clear, 

 if  you  aren't  good  at reading  color  codes or  if  the marking  has  come  off

 Measure  input  and  output  resistance  of  circuits

Test  and  characterize  sensors  and potentiometers 

Remember

You  can  only  test  resistance  when  the  device  you're  testing  is not  powered.

You  can  only  test  a  resistor  before  it  has  been  soldered/inserted  into  a  circuit. 

You  can  make  sure  your  meter  is  working  well  by  having  a  'reference  resistor'.

Resistance  is  non-directional,  you  can  switch  probes  and  the  reading  will  be  the  same.

(3) Current

Why  Measure  Current? 

If  there  is  not  enough  current,  your  circuit  may  not  be  able  to  do  the  work  it  was  designed  to  do.    Logic  circuits  may  not function  reliably,  displays  may  be  dim,  motors  may  stall.

                                    On  the  other  hand,  if  there  is  too  much  current,  things  will  heat  up  and  components  may  be  damaged.  In  extreme cases  there  may  even  be  smoke  or  flames.

 Reasons  for  measuring  current  in  a  circuit  include: 

Determining  circuit  power  requirements.

Verifying  correct  circuit  operation.

Testing  power  supply  performance.

Verify  that  batteries  are  charging  or  discharging  at  a  safe  rate.

 Estimating  battery  life  or  recharge  time Diagnosing  circuit  problems.

(4) Voltage

To start, let's measure voltage on a AA battery: Plug the black probe into COM and the red probe into mAVΩ.

Voltage  is  the  pressure  that  is  applied  to  a  conductor.  There  are  two  common  types  of power  sources,  Alternating  Current  (AC)  and  Direct  Current  (DC).  Alternating  Voltage  is the  most  common  form  of  electricity.  It  is  the  power  supplied  by  the  utility  or  generators, which  flows  through  our  electrical  circuits.    The  symbol  for  AC  voltage  is V ~ . 

DC  Voltage  is  a  constant  level  of  stored  energy.    It  is  stored  in  batteries  or  converted from  alternating  voltage  through  the  use  of  electronic  rectifiers.    Electronic  products  like TVs,  VCRs and  computer  equipment  run  on  DC  power.     The  symbol  for  DC  voltage  is V---.

(5) capacitance

(6) Diode

Types  of  Multimeters 

There  are  two  common  types  of  Multimeters,  Analog  and  Digital.  Digital  Multimeters (DMMs)  are  the  most  common.    They  use  a  liquid  crystal  display  (LCD)  technology  to give  more  accurate  readings.    Other  advantages  include  higher  input  impedances,  which will  not  load  down  sensitive  circuits,  and  input  protection.   

    

  Analog  meters  use  a  needle  movement  and  calibrated  scale  to  indicate  values. These were  popular  for  years,  but  recently  their  numbers  have  declined.    Every  voltmeter  has  an internal  resistance  or  impedance.  The  input  impedance  of  an  analog  meter  is  expressed  in ―Ohms  per  Volt‖ 

Technical  note:  Analog  Meters     The  internal  impedance  of  the  meter  is  in  parallel  to  the measured  circuit.  You  want  this  impedance  to  have  as  little  effect  on  the  measurement  as possible  so  the  higher  the  impedance  the  better.    For  most  electrical  measurements  this effect  is  minimal,  but  for  sensitive  electronics  of  today  the  effect  of  the  added  resistance could  be  significant.  This  is  just  one  of  the  disadvantages  of  an  Analog  meter.  There  are however  a  few useful  applications  for  analog  meters,  so  they  aren’t  going  away tomorrow. 

The  Digital  Multimeter  (DMMs)  feature  a  digital  or  liquid  crystal  display  (LCD). Measurement  readings  are  displayed  as  numerical  values  on  the  LCD  Display.  The display  also  alerts  you  to  any  pertinent  symbols  and  warnings. 

Technical  Note:  Digital  Multimeters  and  ClampMeters  use  different  techniques  internally,  to measure  AC,  DC  voltage,  Resistance  and  Amperes.  An  advantage  of  a  digital  multimeter is  their  accuracy  and  input  protection.  Their  input  resistance  or  impedance  is  very  high, in  the  range  of  1,000,000  to  10,000,000  ohms,  so  there  is  little  effect  on  the  measurement. On  good  quality  meters,  their  inputs  are  also  protected  from  faults  and  misuse.  Test instruments  today  devote  a  good  deal  of  architecture  to  overload  protection.  Most  digital meters  meet  some  safety  standard  such  as  UL601010  or  IEC  (International  Electrotechnical  Commission).   

soldering

    SOLDERING

                    

                        Soldering is a jointing process used to join different types Electrical or Electronic component together, also metal. 

                    Soldering differs from other metal bonding approaches such as brazing or welding in both the temperatures used to create the bond and the resulting strength of the bond. The generally accepted definition of soldering given by the Welding Society is that soldering takes place at temperatures below (450^oC). Higher temperature bonding processes produce stronger bonds that are not subject to stress-induced creep.

How does it work?

Solder is melted by using heat from an iron connected to a temperature controller. It is heated up to temperatures beyond its melting point at around 450 degrees fahrenheit which then causes it to melt, which then cools creating the soldered joint.

As well as creating strong electrical joints solder can also be removed using a desoldering tool.

Solder is a metal alloy used to create strong permanent bonds; such as copper joining in circuit boards and copper pipe joints. It can also be supplied in two different types and diameters, lead and lead free and also can be between .032" and .062". Inside the solder core is the flux, a material used to strengthen and improve its mechanical properties.

Types of Soldering

There are three types of soldering which use increasingly higher temperatures, which in turn produce progressively stronger joints:

• Soft soldering (90 °C - 450 °C) - This process has the lowest filler metal melting point of all the soldering types at less than around 400°C these filler metals are usually alloys, often containing lead with liquidus temperatures under 350°C. Because of the low temperatures used in soft soldering it thermally stresses components the least but does not make strong joints and is then therefore unsuitable for mechanical load-bearing applications. It is also not suited for high temperature use as this type of solder loses strength and melts.
• Hard (silver) soldering (>450 °C) – Brass or silver is the bonding metal used in this process, and requires a blowtorch to achieve the temperatures at which the solder metals.
• Brazing (>450 °C) – This type of soldering uses a metal with a much higher melting point than those used in hard and soft soldering. However, similarly to hard soldering, the metal being bonded is heated as opposed to being melted. Once both the materials are heated sufficiently, you can then place the soldering metal between them which melts and acts as a bonding agent.

What metal used In solder?

                                                     

                              Solder is basically metal wire with a "low" melting point, where low for our purposes means low enough to be melted with a soldering iron. For electronics, it is traditionally a mix of tin and lead. Tin has a lower melting point than Lead, so more Tin means a lower melting point.

              Soldering tools and safety tools

1. Soldering iron

2. Soldering wire

3. Wire cutter

4. Solder sucker

5. Solder wick

6. Treezers

7. USB microscope

8. Wet sponge

9. Soldering stand

10. Safety glasses

11. Hand gloves

12. Mask