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in case you don't want to read the padlet all the information is in these links

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Electricity is one of the most important blessings that science has given to mankind. It has also become a part of modern life and one cannot think of a world without it. Electricity has many uses in our day to day life. It is used for lighting rooms, working fans and domestic appliances like using electric stoves, A/C and more. All these provide comfort to people. In factories, large machines are worked with the help of electricity. Essential items like food, cloth, paper and many other things are the product of electricity.

Modern means of transportation and communication have been revolutionised by it. Electric trains and battery cars are quick means of travel. Electricity also provides means of amusement, radio, television and cinema, which are the most popular forms of entertainment are the result of electricity. Modern equipment like computers and robots have also been developed because of electricity. Electricity plays a pivotal role in the fields of medicines and surgery too - such as X-ray, ECG. The use of electricity is increasing day by day.

Lekshmi S. is a Std X D student at V.H.H.G.S.S., Pattathanam

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Electricity is one of the most important blessings that science has given to mankind. It has also become a part of modern life and one cannot think of a world without it. Electricity has many uses in our day to day life.

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Maths

Science

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You can download our open textbooks in different formats to use them in the way that suits you. The files can be big, so we don't make them available from our mobi site (the one you're currently viewing). Visit the desktop version of the site to access the download files for all of our titles.

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Have you ever wondered what happens when you flip a switch to turn on a light, TV, vacuum cleaner or computer? What does flipping that switch accomplish? In all of these cases, you are completing an electric circuit, allowing a current, or flow of electrons, through the wires.

An electric circuit is in many ways similar to your circulatory system. Your blood vessels, arteries, veins and capillaries are like the wires in a circuit. The blood vessels carry the flow of blood through your body. The wires in a circuit carry the electric current to various parts of an electrical or electronic system.

Your heart is the pump that drives the blood circulation in the body. It provides the force or pressure for blood to circulate. The blood circulating through the body supplies various organs, like your muscles, brain and digestive system. A battery or generator produces voltage -- the force that drives current through the circuit.

Take the simple case of an electric light. Two wires connect to the light. For electrons to do their job in producing light, there must be a complete circuit so they can flow through the light bulb and then back out.

The diagram above shows a simple circuit of a flashlight with a battery at one end and a flashlight bulb at the other end. When the switch is off, a complete circuit will not exist, and there will be no current. When the switch is on, there will be a complete circuit and a flow of current resulting in the flashbulb emitting light.

Circuits can be huge power systems transmitting megawatts of power over a thousand miles -- or tiny microelectronic chips containing millions of transistors. This extraordinary shrinkage of electronic circuits made desktop computers possible. The new frontier promises to be nanoelectronic circuits with device sizes in the nanometers (one-billionth of a meter).

In this article, we'll learn about the two basic types of electric circuits:

Power circuits transfer and control large amounts of electricity. Examples are power lines and residential and business wiring systems. The major components of power circuits are generators at one end and lighting systems, heating systems or household appliances at the other end. In between are power lines, transformers and circuit breakers.

Electronic circuits process and transmit information. Think computers, radios, TVs, radars and cell phones.

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Have you ever wondered what happens when you flip a switch to turn on a light, TV, vacuum cleaner or computer? What does flipping that switch accomplish? In all of these cases, you are completing an electric circuit, allowing a current, or flow of electrons, through the wires.

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600BC: Static electricity
Thales, a Greek, found that when amber was rubbed with silk it attracted feathers and other light objects. He had discovered static electricity. The Greek word for amber is ëelectron', from which we get ëelectricity' and ëelectronics'.

1600: William Gilbert invented the term electricity
William Gilbert, scientist and physician to Queen Elizabeth I, invented the term electricity (from the Greek word for amber, elecktra). He was the first person to describe the earth's magnetic field and to realise that there is a relationship between magnetism and electricity.

1705: Francis Hauksbee invented Neon Light
Francis Hauksbee created electrical effects by putting some mercury into a glass globe, pumping out the air and then spinning it. When he did this in the dark, and then rubbed the globe with his bare hand, it glowed. (He didn't realise it, but he had invented the neon light!)

1752: Franklin proved that lightning is a form of electricity
Benjamin Franklin, famous U.S. politician, flew a kite with a metal tip into a thunderstorm to prove that lightning is a form of electricity. He was very lucky he wasn't killed. Don't try this at home!

1700s: The Wimshurst machine was invented
The Wimshurst machine was invented. It is used to produce static electricity easily and reliably. Two parallel plates are rotated in opposite directions, which produces a charge around the edges of the plates. The charge is collected by a system of combs.†Voltages as high as 50,000 volts can be produced, depending on humidity and other conditions, as well as sparks up to four inches long.

1780: Luigi Galvani's dead frog's legs
An Italian called Luigi Galvani discovered that when he touched a dead frog's leg with a knife, it twitched violently. Alessandro Volta later showed that this was because electricity is created when moisture (from the frog) comes between two different types of metal (the steel knife and a tin plate).

1800: Volta's Pile
Volta created the first simple battery. He used pure silver and zinc discs, sandwiched between muslin damped in a salt solution, developed from Galvani's earlier experiments with a frog's leg.

1800: Sir Humphry Davy discovered Electrolysis
Sir Humphry Davy discovered that when he passed an electric current through some substances they decomposed. This process later became known as electrolysis. Davy's experiments with electrolysis led to the discovery of a number of elements, including magnesium, calcium, strontium and barium.

1820: Hans Christian Oersted discovered magnetic fields caused by electricity
Hans Christian Oersted of Denmark found that when electricity flows through a wire, it produces a magnetic field that affects the needle of a nearby compass.

1821: Michael Faraday's discovery that led to the invention of electric motors
Michael Faraday discovered that when a magnet is moved inside a coil of copper wire, a tiny electric current flows through the wire. This discovery later led to the invention of electric motors.

1821: Thomas Johann Seebeck discovered Thermo-electricity
Thomas Johann Seebeck found that when the junction of certain metals is heated, electricity flows ñ thermo-electricity.

1826: André Ampère explained the electro-dynamic theory
André Ampère published his theories about electricity and magnetism. He was the first person to explain the electro-dynamic theory. The unit of electric current was named after Ampère.

1827: Georg Ohm published his complete mathematical theory of electricity
German college teacher Georg Ohm published his complete mathematical theory of electricity. The unit of electrical resistance was later named after him.

1829: Joseph Henry's discovery into electromagnetism
Joseph Henry showed that a wire wrapped in coils produces a greater electromagnetism than a straight one.

1830: Joseph Henry discovered the principles of the dynamo
Joseph Henry discovered the principles of the dynamo.

1831: Michael Faraday demonstrated electromagnetic induction
Michael Faraday demonstrated electromagnetic induction by passing a magnet through a coil of wire.

1831: The First Telegraph Machine
Charles Wheatstone and William Fothergill Cooke created the first telegraph machine.

1834: Charles Wheatstone measured the velocity of electricity
Charles Wheatstone used a revolving mirror and four miles of wire to measure the velocity of electricity.

1838: Samuel Morse invented Morse Code
At an exhibition in New York, Samuel Morse demonstrated sending 10 words a minute by his new telegraph machine. He used a system of dots and dashes, which later became standard throughout the world, known as Morse code.

1870s: Thomas Edison built a DC electric generator
Thomas Edison built a DC (direct current) electric generator in America. He later provided all of New York's electricity.

1876: Alexander Graham Bell invented of the telephone
Alexander Graham Bell, inventor of the telephone, used electricity to transmit speech for the first time.

1878: Joseph Swan demonstrated the first Electric Light
Joseph Swan, a British scientist, demonstrated the first electric light with a carbon filament lamp. A few months later, Thomas Edison made the same discovery in America.

1880s: Nikola Tesla developed an AC motor
Nikola Tesla developed an AC (alternating current) motor and a system of AC power generation. Edison saw Tesla's system as a threat to his DC supply and spread stories that it wasn't not safe. But, after Tesla's system was used to power 100,000 electric lights at Chicago's World Fair in 1893, AC became the established power supply in the USA.

1880s: Nikola Tesla invented the Telsa Coil
Nikola Tesla used the ëTesla coil' to step up ordinary household current to produce extremely high frequency current. Tesla used this high frequency current to develop some of the first neon and fluorescent lights.

1881: The first public electricity supply
The first public electricity supply was generated in Godalming, Surrey using a waterwheel at a nearby mill.

1883: Magnus Volks built the first electric railway
The first electric railway opened on Brighton seafront, built by electrical engineer Magnus Volks. The Volks Railway, built just for pleasure rides, is one mile long and still runs during the summer season.

1884: Charles Parsons built his first turbine
Charles Parsons built his first turbine. This is a type of engine which is operated by jets of high pressure gases. This type of engine was later developed to drive the propellers of boats, including the Titanic.

1886: Heinrich Hertz produced and detected electric waves
Heinrich Hertz produced and detected electric waves in the atmosphere.

1890: Turbine driven generators
Turbine driven generators were introduced to produce electricity.

1892: Hendrik Lorentz published his electron theory.
Dutch physicist Hendrik Lorentz published his electron theory.

1895: The first electric hand drill
The first electric hand drill became available, invented by Wilhelm Fein.

1895: Discovery of X-rays
The German phsyicist Wilhelm Roentgen discovered invisible rays that made a distant screen glow and passed through objects. These were X-rays.

1896: Nikola Tesla's hydroelectric power generators
Nikola Tesla's hydroelectric power generators at Niagara Falls came into operation. Within a few years, Tesla's generators at Niagara Falls were supplying electricity to New York City for the elevated railways, the subways and even the lights on Broadway.

1897: Marconi sends radio message
Guglielmo Marconi sends a radio message from The Isle of Wight to Poole (20 miles away). Later he sends a message across the Atlantic.

1905: Albert Einstein and photovoltaic cells
Albert Einstein demonstrated that light energy could be used to produce electricity ñ the idea behind photovoltaic cells was born.

1918-19: Washing machines and refrigerators
Electric washing machines and refrigerators first became available.

1926: First National Grid was introduced
Electricity Supply Act ñ the first National Grid was introduced.

1930-40s: Hydro-electric power stations
Hydro-electric power stations were built in Scotland and Wales, but the majority of electricity generation was from burning coal.

1930-40s: Electrical household appliances introduced
Mains powered radios, vacuum cleaners, irons and fridges were becoming part of every household.

1936: John Logie Baird pioneered the television.

1956: First large-scale nuclear power station
The world's first large-scale nuclear power station opened at Calder Hall in Cumbria. The reactors were a prototype of the Magnox gas cooled reactor.

1960s: Advanced gas cooled reactors
The UK decided to develop advanced gas cooled reactors to succeed the earlier Magnox stations. Around the same time, France and the USA decided to adopt water cooled reactor technology.

1994: The UK's first pressurised water reactor
The UK's first pressurised water reactor (PWR) was opened at Sizewell B in Suffolk. It had taken 7 years to build, after the largest ever public enquiry in the UK. No further nuclear reactors have been built in the UK since then.

2000: The world's first commercial wave power station
The world's first commercial wave power station on the Scottish island of Islay began to generate electricity. Devices are placed on the shoreline or out at sea that use wave motion to compress air to drive a turbine or hydraulic pumps. The station is called LIMPET (Land-Installed Marine-Powered Energy Transformer) and can provide enough electricity for about 400 homes.

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600BC: Static electricity Thales, a Greek, found that when amber was rubbed with silk it attracted feathers and other light objects. He had discovered static electricity. The Greek word for amber is ëelectron', from which we get ëelectricity' and ëelectronics'.

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developed electric power plants for New York City as well as many electrical devices which influenced life around the world, including the dimmer switch and screw-in fuse.

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Pioneer of the transformer and alternating current (AC) distribution.

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He fostered the development of alternating current that made possible the expansion of the electric power industry in the United States

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Another example of how a circuit works together is with a flashlight, it has a switch, a battery, and wires this one is very simple again the battery passes electricity through the wires and when you push the switch the light turns on.

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Every component of a circuit needs to function together for a circuit to work; they each follow a role of their own kind of like your body. Every body part has its own role to allow our body to function properly. It's the same with a circuit but in this case we need to have electricity flow.

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A circuit usually always has these 3 things, a battery, bulb, wires, and a switch but a circuit will still work without a switch if constructed properly.

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Each electrical component has its own role in a circuit and all these roles work together to form a functional circuit. For example, a simple one is a light bulb. The electricity comes from a power supply or it can even come from a battery, it’s the chemicals inside the battery which make electricity, wires are connected to the positive and negative sides of the light bulb this way the battery and wires work together to make electricity flow through a light bulb allowing it to glow.

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Have you ever thought of how turning on a TV works in our homes? Or how just by a push of a button we are able to turn on a light? What happens by the push of a button?
With all of these things an electrical circuit is formed, it allows current flow through wires to allow our lights to on or our devices to function and so on.

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How do different parts of an electrical system work together to enable devices in our homes

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If we place a resistor in series it increases the resistance in the circuit. Hence, the current flowing through the light bulb decreases. The light bulb becomes dimmer.

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The placement of the resistor also changes the outcome of a circuit, if we place a resistor in parallel decreases the resistance in a circuit. Hence, the current flowing through the light bulb increases. The light bulb becomes brighter. 

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If the resistance decreases then, this means that if the voltage is high the current is high, and if the voltage is low the current is low. Similarly, if we increase the resistance, the current goes down for a given voltage and if we decrease the resistance the current goes up.

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When you add a resistor to a circuit, the resistance in a circuit increases. Adding more resistance increases the opposition to the flow of charge so it is more difficult for charge to move through the circuit. Therefore there is less current (as current is the rate of flow of charge). 

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Resistors are used to introduce precise amount of resistance in the electrical circuit to reduce the current flow

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Electricity is the most easily controlled form of energy and has various uses in our daily life. It's a very important part of it. If it wasn't for electricity i wouldn't be able to type this information out right now. Even if it doesn't seem like it we wouldn't be able to survive without electrical systems in today's time. We gain all our comfort and relaxation from electricity. We use it to charge our devices that we use throughout the day constantly with so much information on our fingertips and our loved ones being a text away when in reality they may be miles apart from us. We use electricity for light during the nighttime to see. Many appliances such as air conditioners fans and electrical kitchen equipment may be supported with electricity. We use it for heating, refrigeration, public transportation systems, cooling etc. The basic use of electricity is to work different types of appliances in our homes and workplaces. Life would be a lot harder than electricity if we think about it really. It would be harder to store data and we wouldn't have such advanced technologies and cures many diseases.

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Resistors are used to introduce precise amount of resistance in the electrical circuit.

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Switch: A switch is an electrical component that can disconnect or connect the conducting path in an electrical circuit

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A Simple Circuit

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In a parallel circuit, there is more than one resistor (bulb) and they are arranged on many paths.

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Electricity is a natural phenomenon that occurs throughout nature and takes many different forms.
Electricity is all around us--powering technology like our cell phones, computers, lights, soldering irons, and air conditioners. It's tough to escape it in our modern world. Even when you try to escape electricity, it's still at work throughout nature.

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Voltmeter: we measure potential difference using a voltmeter.

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Ammeter: we measure current using an ammeter.

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The defining characteristic of a series circuit is that there is only one path for current to flow.