COMPUTER AND ELECTRICAL CONNECTIONS....

     

     Have you ever experience electrical shocks when you touch your computer , refrigerator, washing machine when they are in use ? Or Have you ever experience power cut while its not from the supply company (i.e. there is electricity in your surrounding exept your house or room ? Let us now discuss over these facts along with some information on electrical connections in our houses.

     The electric supply companies delivers AC (220 Volt, 50 Hz) through supply lines (wires mainly of Aluminium). These lines are called Phase or Live wires. there is also a neutral wire which completes every household circuit.

MAIN SWITCH or FUSE

   

     The LIVE and NEUTRAL wires are first connected to the Main Switch. Then the Live wire is fed to a Meter which measures electrical energy consumption. Fuse are connected for security. A Fuse wire is an Alloy of Tin and Lead (75% Sn + 25% Pb). It has Higher resistivity but lower melting point. Thus if for any reason current of the supply line increases, it melts and disconnect the household circuit from the main line.

 DISTRIBUTION BOARD

        Live wire from the main switch is connected to the distribution board through another fuse. From fuse the wire is fed to different switches for different appliances. There are switches, three pin plugs, indicators in a board. The live wire is first connected to the switch for the three pin plug , then from switch the wire is connected to the thee pin plug's one side ;from there to all other switches. The neutral wire starts from the appliances and ends at the three pin plug's second side and from there the wire goes to the neutral wire of the distribution line.

SWITCH

       A switch is a circuit component that can make a circuit open or close with a stroke. It is such configured, that by the help of a spring and a lever it can connect or disconnect two points. One of those point is connected to the Live wire and the other is connected to the appliance. If by stroke we make the Switch 'on' then current flows up to the appliance. The second end of the appliance is connected to the Neutral wire of the supply line.

 THREE PIN PLUG

       There are some electrical appliances such as Computers, Refrigerators, Washing machines, are used temporarily.These are connected to the supply line through Three Pin Plug. There are three wires in a three pin plug. One is Live , the second is neutral and the third is Earth .These wires are of different colours The Live wire is Red or Brown. The Neutral wire is Blue or Black. The Earth wire is Green. The color code is maintained during wiring so that any one can recognize the wires later.

EARTHING
       The Earthing is done by metallic rod and broad gauge wire . At first we dig a little. the wire is connected to the rod and the rod is buried in the pit.then  we pour plenty of salt and charcoal there. This wire is connected to the electrical switch board . the earth wire of three pin plug is connected to this wire.

        During use electrons gather on the  outer metallic surface of some household appliance. Heavy gathering may damage the appliance. These electrons are carried to earth by this Earth wire. If Earthing is not good enough then you may experience a shock when you touch the electrical appliance.

CONNECTION OF A PC
         
          If you want to use a PC at your home then at first make a good electrical wiring with very good earthing. If you are using UPS( un-interepted power supply- i.e. if there is a load shedding it can feed back power for almost 30 to 40 minutes) then connect its three pin plug to the three pin socket of the switch board.There are three Three Pin Sockets at the back of the UPS. Here we connect monitor, cpu and music system power chords. 

SWITCHING ON A PC

Firstly switch on the switches on the switch board. 
For UPS to use, turn on its switch on its front side ( some times on the backside)    
Turn on the power button on the CPU  
Wait a while ..... It will run automatically


  

DEVELOPMENT OF ELECTRICITY......

DEVELOPMENT OF ELECTRICITY......

   Who had discovered first electric cell ? or, who made today's method of power generation easier? Let us have a quick view through the history of power generation.

   The first man to make a cell was Alessandro Volta in the year 1800 AD . He made a pile of  Zinc and Copper plates one after another and separating them with wet cloths dipped in Sulfuric acid. Later years electric cell was formed using the Volta's idea.

SIMPLE VOLTAIC CELL

      STRUCTURE

           Two plates one of Zinc And the other Copper is partly immersed in dilute Sulfuric Acid taken in a pot. This makes a Simple Voltaic Cell. The Copper plate becomes positive and the Zinc plate becomes negative. If we connect them with a conducting wire then electric current flows.

      WORKING

                In simple Voltaic cell Chemical energy is transformed into electrical energy. This incident was discovered by famous scientist Galvani of Italy.

   

         Change in the Solution

           Molecules of the dilute Sulfuric Acid dissociates into Hydrogen and Sulfate ions

  

                H₂SO₄↔ 2H⁺+SO₄^-2

        

Reaction at zinc Plate

              In this plate Zn atoms free two of its atomic electron and transforms into Zn ions. These electrons stay on the  Zn plate and make it negative. The Zn ions come into the solution.There it combines with Sulfate ions to form Zinc-Sulfate.

                    

                        Zn-2e↔Zn⁺² 

                               Zn⁺² + SO₄^-2  = ZnSO₄ 

       

         Reaction at Copper Plate

              The Hydrogen ions come to copper plate and take electrons from there. Hydrogen ion first turns into atom .Thus Copper plate becomes positive and Hydrogen gas is generated.

 

                        H⁺ +e=H

After this various electric cell was made. Of them Lech lance cell Lead acid cells are popular.But interesting one was the dry cells.

  DRY CELL

     To make a dry cell we need a cylinder of Zinc.Here we take Ammonium Chloride as electrolytic medium. A carbon (graphite) rod is used as the second electrode while the Zn cylinder is the first one. The electrolyte at first dissociates in to ions. Zn plays same role as in case of Simple Voltaic Cell; but this time it produces Zinc Chloride. The Carbon rod acts as copper plate in Simple Voltaic Cell. But here along with Hydrogen Ammonia is generated.

The reactions occur in the dry cell is as follows: 

NH₄Cl↔NH₄⁺+Cl^-

Zn-2e↔Zn⁺² 

Zn⁺²  + 2Cl^- =ZnCl₂ 

2NH₄⁺+2e=NH₃+H₂