TEMA 7 LA ELECTRICIDAD 1ESO 15 16 ENG trad no revisada

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(1)ELECTRICITY. Luis Garcia Molina. I.E.S. Serra Perenxisa (Torrente). 1.

(2) Index I.NATURE OF ELECTRICITY II.ELECTRICAL POWER III.ELECTRICAL CIRCUIT IV. CONNECTION IN SERIES AND PARALLEL V.KEY FIGURES OF ELECTRICITY AND THE LAW OF OHM. 2.

(3) I-NATURE OF ELECTRICITY. 3.

(4) STATIC ELECTRICITY • Although not know what it was, electricity is manifested in phenomena known since ancient times. ACTIVITY 1.1: ANSWER, why occur these. 4.

(5) static electricity The matter is made of atoms. Atoms have a nucleus with positively charged and a negatively charged electrons orbiting. • Like charges repel. • And loads of different signs attract. Normally they are in balance and nothing happens.. -. +. -. -. If due to other energies and forces the charged particles are arranged ... potentially accumulate power, Well either positive or negative charges. - So that at any time can jump A SPARK negative charges formed by jumping into the positive. Or even they can get to attract a piece of whole matter (piece of paper, hairs ...). +. +. +. ---. ---. +. +. ---. ---. +. + ---. +. +. - --- -. ---. + ---. +. +. ---. ---. +. +. ---. ---. +. +. - --- -. ---. ---. +. +. + ---. -. attraction. -. -. +. +. +. +. +. ---. ---. ---. ---. ---. +- + ---. ---. +. +. --- ---. + ---. +. +. +. +. +. +. +. ---. ---. ---. ---. ---. ---. ---. +. +. --- ---. + ---. PAPER. 5.

(6) Nature of electricity •. •. •. Well, in the early twentieth century (1900-2000) everyone knew that the matter had positively charged particles and negatively charged particles, which could be moved. He also knew that matter was made of atoms (atomic theory Dalton). To find out exactly what was electricity, it was not until 1900When JJ Thompson and his students demonstrated in Rutherford Rutherford atomic model atoms were composed of: – a core with protons with positive charge and neutrons no load. – and a Electrons with negative charge around the nucleus they could spend a few atoms and moving others.. 6.

(7) The atom: the electron current. Electrons (-). Protons (+) CORE Neutrons (0). 7.

(8) Nature of electricity Here is a conductor (a metal such as copper) material. It consists, of course, copper atoms with their protons (+, blue) and its Electrons (-, Orange). Thus, as is now not occur absolutely nothing !!. What to do to start a few electrons and moving them ?: Must be connected to a source of "electricity or VOLTAGE" (a 8 generator)..

(9) Now, the electrons are set in motion, if: 1-CONNECT the conductive metal to a generator of voltage and 2-CLOSED circuit connecting + and one end to another to - the stack. We already have a. CIRCUIT ELECTRIC. -. + 9.

(10) MATERIALS conducting and nonconducting Although we connect to a pile and let us close the electrical circuit, not all materials have electron atoms subside.. •. Call Conductive materialsTo those whose atoms easily give electrons when subjected to voltage. While the power lead. – Example. METALS (such as copper, aluminum ...). •. Call INSULATION MATERIALS or drivers, those whose atoms do not easily give electrons. Not conduct electricity. – Example: wood, plastic, stone .... •. Call SEMICONDUCTOR MATERIALS those whose atoms give electrons limited and controlled manner. They need to be doped with small amounts of other atoms. – Example: germanium, silicon, gallium-doped or Arsenio.. 10.

(11) MATERIALS conducting and nonconducting Activity 1.2: Di which of these materials conduct electric current and which are not: -a boat refrescto -a pencil -a bic pen -a old pen -a key -..... Activity 1.3: Why electrical cables have a copper core and a layer of plastic on the outside?. 11.

(12) Activity 1.4: to) What particles form the atomic power? b) Electrons do they come out of the pile driver or cable? c) What is the role of the generator? d) How they are set in motion? e) make a comparison between an electric circuit and a water circuit with a hydraulic pump. NOTE: The battery does not give electrons. Provides strength to move: Here you have two comparisons: -AIR Duct: Electron air Voltage generator: the fan. 12.

(13) II-TO POWER. 13.

(14) ELECTRIC POWER Energy is all that can move, heat, light or transmit things. Electricity is energy.. •. •. The bulbs use electricity to produce light energy. Light is light energy.. Electric motors use electric energy to produce movement. The movement is Kinetic energy.. •. Electric stoves use electricity to produce heat energy. Heat is thermal energy.. Pictures: cocodrile clips.. 14.

(15) INTRODUCTION: electricity WHAT IS ELECTRICITY? •. Remember that Electricity is a secondary energy, Obtained from natural sources of primary energy, – LOCATION: Power stations – APPLIANCE: Electric generator (Turbinegenerator set) – ENTERS: Primary energy sources – SALE: AC electricity.. ENTERS: Power source. transformer GENERATOR turbinealternator. POWER. Network transport OUT: electric power. T 15.

(16) Activity 5.1Make a list of your daily activities in which you use electricity. – To warm things. – To move things. – To illuminate. – Telecommunications. Activity 5.2: Draw the scheme of obtaining the eletric energy and describes the process with your words.. 16.

(17) III-THE ELECTRICAL. 17.

(18) CONCEPTS To study and work with the electricity we need to know its fundamental concepts: •. Electron: Subatomic particle with a negative charge (-).. •. Electric current: flow of electrons through a conductive material.. •. Electrical circuit: closed path along which electrons. It consists basically of: – 1. The conductive material, Yielding electrons. – 2. The electric generatorWhich creates the electrical voltage to moving electrons. – Maneuvering 3.Elementos, That can regulate the flow of electric current in accordance with our needs. – 4.Aparatos receivers, Which use the energy of the electrons and transform it into light, heat or movement. 18.

(19) CONCEPTS ACTIVITY 2.1What are and what kind of component pertencene these individual items?. ACTIVITY 2.2 Draw an electrical circuit with these items.. 19.

(20) 1-CONDUCTOR ELEMENTS •. DEF. Cables are metallic materials which yield the electrons, which are moving through them (they are coated with insulating plastic) – Structure:. Insulating material so that no current is leaking. Materials Insulation: -PVC. Materials drivers: Conductive material giving electrons and circulate through which the same. -Copper, aluminum. – Symbol: Easy, right?. 20.

(21) 2-GENERATORS •. DEF. Are the devices that create energy or voltage or voltage (V) required for the electrons of the atoms jump and put into circulation.. Symbols. BATTERY:. •. Alternator:. Battery. TYPESAs you know them.. Zinc-carbon battery BATTE RIES GENERATORS CHEMICALS ELECTRICAL GENERATORS. Battery Lead ACUMULADORES. GENERATORS ELECTROMAGNETIC. Mercury battery. Nickel-cadmium battery. Direct current. Dynamo. AC Power. Turbine-alternator 21.

(22) CHEMICAL GENERATORS: BATTERY •. Chemical generators create electricity from join two types of substances: A gives electrons and another that takes. They are the batteries (they are rechargeable). • Zinc-carbon battery. (Normal batteries and pouch) • Zinc-mercury battery (button cells) • Battery Lead (car batteries) • Nickel-Cadmium battery. • D'hidrógeno battery (Car batteries future loss) • Nickel-metal hybrid • Lithium ion battery (batteries Mobil) Electrons. Electrolyte If a cable together with the electrons are on the cable and can use. Electrons. Substance that gives electrons. Substance that takes electrons. 22.

(23) Electromagnetic generator. http://www.artinaid.com/2013/04/que-es-un-generador-electrico/. 23.

(24) Electromagnetic generator • ACTIVITY 2.3: Name the parts of the alternator.. http://acer.forestales.upm.es/basicas/udfisica/asignaturas /fisica/magnet/generador.html. Stator, rotor, magnetic poles, coil, brushes ... 24.

(25) 3-ELEMENTS OF OPERATION • DEF. Are the elements that allow us to decide if the current passes or fails: – PUSH: Operating element that when pressed the current passes and if you release the short.. Symbol:. – SWITCH: Operating element which has two positions: When closed the current passes and when open no.. – SWITCH: Operating element with two positions: On a current sent one way and in another position sends another way 25.

(26) 4-ELEMENTS RECEIVERS • DEF. Are the elements to be traversed by the current transform the electrical energy of the electrons in other types of energy: – BULBS : Receiver that converts electrical energy into light (and heat) element. – RESISTANCE: Receiver that converts electrical energy into heat. – ELECTRIC MOTOR: Receiver that converts electrical energy into kinetic energy (movement) Item. – BUZZER, RING: Receiver that converts electrical energy into sound energy element.. 26.

(27) Schemes symbols •. ACTIVITY 2.5: Draw using the symbols adecuadoos the electrical plans consist of:. •. a) Generator, pushbutton, 2 consecutive bulbs.. •. b) 2 generators in series, one switch, one bulb and 1 motor in series.. •. c) one generator, one switch that carries two lines: one line with 4 bulbs in series, and another line with a 1 motor and 2 buzzers in series.. •. d) 2 generators in series, one switch and three resistors in parallel.. 27.

(28) IV-CIRCUITS IN SERIES CIRCUITS IN PARALLEL. •. ACTIVITY 3.1Now let's draw a circuit with two bulbs. They can be connected in two ways, to see if you guess:. •. We can do it in two ways: – Putting the bulbs in series – Putting the bulbs in parallel.. 28.

(29) Series connection •. What you probably did was put two consecutive bulbs. That's put two receivers in series.. •. The same circuit with electrical symbols is as follows:. •. In this case the two bulbs the battery power is distributed, and shine half of what they could. 29. Pictures: cocodrile clips..

(30) Problems connected in series •. 1) If the fuse blows a bulb, all the others will not work either.. ! FUNDIDA¡ They. can not pass electrons. •. Although not melt does not work, because the electrons do not reach.. 2) spread BULBS ENERGY BATTERY, and shine bit. Both low to no light bulbs and have to spread the battery power.. 6 Volt. 12V. Pictures: cocodrile clips.. 6 Volt.

(31) Parallel connection •. But we can do the same spending less and less wire switches:. •. Este circuit operates as if Foren two independents circuits, I peretes ambdues butt I shine equally.. 31 Pictures: cocodrile clips..

(32) Advantages of the paralleling •. 1) IF A BULB FUNDE the others if they can continue working.. CAST!. The bulb 2 does that can shine even La 1 is melted, because if electrons reach their proio way.. •. 2) Each bulb takes all the energy available from the battery. All shine the most.. 12V. 12V 12V. Pictures: cocodrile clips..

(33) Schemes symbols •. ACTIVITY 3.2: Draw the appropriate symbols using the electrical plans consist of:. •. a) Generator, push button, 2 bulbs in series.. •. b) Generator, switch and two bulbs in parallel.. •. c) Generator, switch and one light bulb and a series motor.. •. d) Generator, switch and one light bulb and a motor in parallel.. •. e) generator, switch and bulb and a motor 1 in series, both in parallel with two series resistors.. 33.

(34) Schemes symbols •. ACTIVITY 3.2: Draw the appropriate symbols using the electrical plans consist of:. •. a) Generator, push button, 2 bulbs in series.. •. b) Generator, switch and two bulbs in parallel.. •. c) Generator, switch and one light bulb and a series motor.. •. d) Generator, switch and one light bulb and a motor in parallel.. •. e) generator, switch and bulb and a motor 1 in series, both in parallel with two series resistors.. 34.

(35) V-KEY FIGURES ELECTRICITY and Ohm's Law. 35.

(36) Magnitudes of electricity Magnitudes They are measurable things. For example, the distance is a quantity to measure the space. Its unit of measurement is the meter, its multiples (Dm, Hm, Km) and sub (dm, cm, mm). •. To work with electricity there are some variables that we need to know: – Current intensity (I) – VOLTAGE (v) – Electrical resistance (R). •. The figures also have their – definitions – Symbols – units, multiples. – Measuring devices. •. Once the know see that there is a mathematical-physical relationship between them. – Ohm's law. 36.

(37) CURRENT INTENSITYSymbol "I". – Definition: Number of electrons passing a time point of the circuit. – Unit: Ah, symbol "A". • Submultiple most common: milliamp (mA) = 0.001 A. – Measuring device: Ammeter. Sign of the device:. TO. 37.

(38) We measure the amperage. We measured with an ammeter. Must be put in series, that is, I merged back into the circuit.. The measurement results for Example 3A intensity. This means you are spending 3 coulombs of electrons per second per circuit.. Fif tee T n. O. -. +. 38.

(39) VOLTAGESymbol "V".. – Definition: Amount of energy from the generator to set in motion the electrons. It can also be defined as the difference in available energy between two points of the circuit to move electrons. – Unit: Volt, symbol "V" (Yes, it matches the magnitude). • More common multiple: kilovolt (KV) = 1000 V. • Submultiple most common: millivolt (mV) = 0.001 V. – Measuring deviceVoltmeter. Sign of the device: V. 39.

(40) We measure the voltage. We measured with a voltmeter. Must be put in parallel, that is, to put it as an alternative route to the circuit.. Moreover, thin batteries have 1.5V to 4.5V energía.Las pouch batteries. There 9V batteries. The button are Car batteries have 12 or 24 V.. Energy between points A and B is for example 1.5 V. This means that the direncia energy available to move electrons between A and B is 1.5 V.. Fif tee V n. •Point Y Uncut! •Point X. -. + 40.

(41) RESISTANCESymbol "R". – Definition: Opposition to current flow. • Moving electrons collide with atoms of the cables, devices etc. The more bump has more resistance. • Moreover, remember that atoms of insulating materials even loose electrons. They are therefore much more resistance to movement of electrons. – Unit:Ohm symbol "Ω". • More common multiple: kiloohmio (KΩ) = 1000 Ω. • Submultiple most common: milliohm (mΩ) = 0.001 Ω. – Measuring device: Ohmmeter. Sign of the device: R. 41.

(42) We measure the electrical resistance We measured with an ohmmeter: It is made with the circuit switched !. The resistance between points A and B is for example 5 Ω .. Fif tee R n. •Point B. •Point A. -. + CIRCUIT OFF! 42.

(43) Measurements: the meter 3 devices usually come together in a measuring device called tester or multimeter. Choosing what we want to measure and measure laying cables in their proper place this unit functions as – ammeter or – voltmeter or – ohmmeter.. 43.

(44) • ACTIVITY 4.1Complete the following table.. Magnitude and symbol. Definition. Unit of measure and symbol. Measuring apparatus and symbol. Instructions for measuring. Intensity (I). 44.

(45) Ohm's Law •. And you know, now you'll see:. •. ANSWER: – If the battery has more energy, electrons move more or less? That is, more voltage amperage more or less? – If the circuit has put more problems to the passage of electrons, electrons circulate there will be more or less ?. That is, more electrical resistance amperage more or less?. 45.

(46) Ohm's Law •. Indeed: – A higher voltage more intensely. • This in mathematics is called a direct relationship between two variables. That is, more than one over the other thing. – A more resistance less intensity. • This math is called an inverse relationship between two variables. That is, more than one within the other and vice versa. – This is expressed in a mathematical formula discovered George Simon Ohm:. V I = R 46.

(47) •. ACTIVITY 4.2:to) Calculated using Ohm's law the value of the current in the following circuit:. 2Ω. 1.5 V. •. b) Calculate the current of this circuit:. •. c) Calculate the intensity of a generator circuit with a 4.5 V and a total resistance of 0.1 Ω. 47 Pictures: cocodrile clips..

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